Total hip or knee replacement (also called total joint arthroplasty) is highly successful at relieving pain and restoring function, but at the risk of acute kidney injury, which is a sudden loss of renal function. Various factors have been associated with this risk, some of which are potentially modifiable, notably, the use of nephrotoxic antibiotics and other drugs.

This review examines the incidence of acute kidney injury using current criteria in total joint arthroplasty of the hip or knee in general, and in the setting of revision surgery for prosthetic joint infection in particular, in which the risk is higher. We identify risk factors for acute kidney injury and propose ways to lower the risk.

MILLIONS OF PROCEDURES ANNUALLY

Total replacement of the hip^1,2 or knee³ is being done more and more. Kurtz et al⁴ estimate that by the year 2030, we will see approximately 3.5 million primary total knee and 500,000 primary total hip replacements every year. In addition, revision total knee procedures are expected to exceed 250,000 per year, and revision total hip procedures are expected to exceed 90,000 per year.⁴

Chronic infection may complicate up to 2% of these procedures and is associated with significant morbidity, death, and financial costs. Currently, it may be the reason for 25% of total joint arthroplasty revisions,⁵ but by the year 2030, it is projected to account for 66% of revision total knee arthroplasties and 48% of revision total hip arthroplasties.⁶

PRIMARY TOTAL JOINT ARTHROPLASTY AND ACUTE KIDNEY INJURY

Study designs, findings varied widely

The incidence of acute kidney injury varied markedly among the studies of primary total joint arthroplasty or revision for aseptic reasons. Numerous factors explain this heterogeneity.

Designs ranged from single-center studies with relatively small numbers of patients to large regional and national samples based on administrative data.

Almost all of the studies were retrospective. We are not aware of any randomized controlled trials.

Discharge diagnosis may miss many cases

Several studies based the diagnosis of acute kidney injury on International Classification of Diseases, Ninth Revision (ICD-9) coding from hospital discharge summaries.

Nadkarni et al,²⁹ in the largest study published to date, used the nationwide inpatient sample database of more than 7 million total joint arthroplasties and found an incidence of acute kidney injury based on ICD-9 coding of 1.3% over the years 2002 to 2012, although this increased to 1.8% to 1.9% from 2010 to 2012.

Lopez-de-Andres et al,³⁰ in a similar study using the Spanish national hospital discharge database, evaluated 20,188 patients who underwent revision total hip or knee arthroplasty and found an overall incidence of acute kidney injury of 0.94%, also using ICD-9 coding.

Gharaibeh et al³¹ used similar methods to diagnose acute kidney injury in a single-center study of 8,949 patients and found an incidence of 1.1%.

Although these 3 studies suggest that the incidence of acute kidney injury is relatively low, Grams et al³⁵ found the sensitivity of ICD-9 coding from hospital records for the diagnosis of acute kidney injury to be only 11.7% compared with KDIGO serum creatinine and urine output criteria. This suggests that the true incidence in these studies may be many times higher, possibly near 10%.

Do all stages of kidney injury count?

Jafari et al,⁷ in a large series from a single medical center, used only the “I” (injury) and “F” (failure) levels of the RIFLE criteria (corresponding to stages 2 and 3 of the KDIGO criteria) and found an incidence of 0.55% in more than 17,000 total joint arthroplasties.

Jamsa et al⁸ used the same criteria for acute kidney injury (only “I” and “F”) and found 58 cases in 5,609 patients in whom postoperative serum creatinine was measured, for an incidence of 1%; the remaining 14,966 patients in their cohort did not have serum creatinine measured, and it was assumed they did not have acute kidney injury. Neither of these studies included the most common “R” (risk) stage of acute kidney injury.

Parr et al³⁶ recently studied a nationwide sample of 657,840 hospitalized veterans and found that of 90,614 who developed acute kidney injury based on KDIGO creatinine criteria, 84% reached only stage R. This suggests that if all stages were considered, the true incidence of acute kidney injury would have been higher—possibly 4% in the Jafari series and possibly 7% in the Jamsa series.

Smaller studies had higher rates

Smaller, single-center series reported much higher incidences of acute kidney injury.

Kimmel et al¹¹ found an incidence of 14.8% in 425 total joint arthroplasties using RIFLE creatinine criteria.

Johansson et al²⁵ found an incidence of 19.9% in 136 total joint arthroplasties using KDIGO creatinine criteria.

Sehgal et al⁹ found an incidence of 21.9% in 659 total joint arthroplasties using AKIN creatinine criteria.

Challagundla et al²⁴ found an incidence of 23.7% in 198 procedures using RIFLE creatinine criteria.

Weingarten et al,¹⁰ in a single-center series of 7,463 total joint arthroplasties, found an incidence of acute kidney injury of only 2.2% using AKIN criteria, although 12% of the patients with acute kidney injury did not return to their baseline serum creatinine levels by 3 months.

Our estimate: Nearly 10%

In total, in the 20 studies in Table 1 that included all stages of acute kidney injury, there were 1,909 cases of acute kidney injury in 34,337 patients, for an incidence of 5.6%. Considering that all studies but one were retrospective and none considered urine output criteria for acute kidney injury, we believe that using current KDIGO criteria, the true incidence of acute kidney injury complicating primary lower-extremity total joint arthroplasties is really closer to 10%.

Various factors have been associated with development of acute kidney injury by multivariate analysis in these studies. Some are modifiable, while others are not, at least in the short term.

Nonmodifiable risk factors

Older age is often significant in studies assessing primary total joint arthroplasty or revision total joint arthroplasty not specifically for infection.^{11,12,16,17,26,28}

Obesity is also a major factor in the development of acute kidney injury,^{7,10–12,17,18} and, along with age, is a major factor contributing to the need for joint replacement in the first place.

Male sex may increase risk.²⁹

Diabetes mellitus was identified as a risk factor in several studies,^10,12,17,20 and hypertension in a few.^7,10,24

Other comorbidities and factors such as cardiovascular disease,^7,10 liver disease,⁷ pulmonary disease,⁷ high American Society of Anesthesiology score,^8,19 and benign heart murmurs preoperatively by routine physical examination have also been linked to acute kidney injury after joint arthroplasty.²⁸

Chronic kidney disease as a risk factor

Chronic kidney disease at baseline was associated with acute kidney injury in several of these series.^{7,11–13,15,19,29}

Warth et al¹² studied 1,038 patients and found an incidence of acute kidney injury of 11% in the 135 with chronic kidney disease (defined as serum creatinine > 1.2 mg/dL) and who received acetaminophen or narcotics for pain control, compared with 4.8% in the remaining 903 patients without chronic kidney disease, who received ketorolac or celecoxib.

Perregaard et al¹³ studied 3,410 patients who underwent total hip arthroplasty and found an incidence of acute kidney injury (per KDIGO creatinine criteria) of 2.2% overall, but 7% in the 134 patients with chronic kidney disease based on KDIGO creatinine criteria.

Nowicka et al¹⁵ found an incidence of acute kidney injury of 16.7% in the 48 patients with chronic kidney disease (defined as a glomerular filtration rate estimated by the Cockroft-Gault formula of less than 60 mL/min/1.73 m²), compared with 4.5% in the remaining 289.

Modifiable risk factors

Modifiable risk factors that should be considered in high-risk cases include anemia, perioperative blood transfusion, perioperative use of renin-angiotensin-aldosterone system inhibitors such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), particular antibiotics used for prophylaxis, and nonsteroidal anti-inflammatory drugs used postoperatively.

Anemia and blood transfusion

Preoperative anemia has been associated with postoperative acute kidney injury in various surgical settings such as cardiac surgery.^37,38 Perioperative red blood cell transfusions have also been associated with acute kidney injury in cardiac surgery; similar results may apply to total joint arthroplasty.

Choi et al,¹⁷ in 2,467 patients undergoing hip replacement, found a significant risk for acute kidney injury if postoperative hemoglobin was consistently below 10 g/dL compared with consistently above this level, with an inverse probability-of-treatment weighted odds ratio of 1.817 (P = .011).

Others have found a significant association of perioperative blood transfusion with acute kidney injury in total joint arthroplasty.^10,29

Nadkarni et al,²⁹ for example, used the nationwide inpatient sample database and found by multivariate analysis that perioperative blood transfusion was strongly associated with acute kidney injury, with an adjusted odds ratio of 2.28 (95% confidence interval [CI] 2.15–2.42, P < .0001).

Comment. A higher incidence of acute kidney injury may represent confounding by indication bias, as sicker patients or complicated surgeries may require transfusion, and this risk may not be completely accounted for by multivariate analysis. It is also possible, however, that transfusions per se may contribute to acute kidney injury. Possible direct or indirect mechanisms mediating acute kidney injury include hemolytic reactions, circulatory overload, acute lung injury, and immunomodulatory effects.³⁹

Preoperative transfusion in anemic patients undergoing cardiac surgery may also reduce the incidence of postoperative acute kidney injury both by correcting the anemia and by limiting the need for perioperative transfusions.⁴⁰ It remains to be determined whether elective preoperative transfusion to correct anemia would reduce postoperative development of acute kidney injury in total joint arthroplasty. As an aside, perioperative transfusion has also been linked to development of periprosthetic joint infection.⁴¹

Renin-angiotensin-aldosterone system inhibitors

Several studies found perioperative use of renin-angiotensin-aldosterone system inhibitors to be a risk factor for acute kidney injury.

Kimmel et al¹¹ reported adjusted odds ratios of 2.70 (95% CI 1.12–6.48) for ACE inhibitor use and 2.64 (95% CI 1.18–5.93) for ARB use in a study of 425 primary total joint arthroplasties.

Challagundla et al²⁴ found an odds ratio of 3.07 (95% CI 1.40–6.74) with ACE inhibitor or ARB use by multivariate analysis in 198 total joint arthroplasties.

Nielson et al¹⁸ studied 798 patients who underwent total joint arthroplasty and found that preoperative use of renin-angiotensin system inhibitors was associated with a significantly higher rate of postoperative acute kidney injury (8.3% vs 1.7% without inhibition), which was statistically significant by multivariate analysis (odds ratio 2.6, 95% CI 1.04–6.51).

We recommend holding renin-angiotensin-aldosterone system inhibitors 7 days before surgery through the postoperative period in high-risk cases.

Aminoglycoside use as a risk factor

Prophylactic administration of systemic antibiotics is the standard of care. In a systematic review of 26 studies and meta-analysis of 7 studies (3,065 patients), prophylactic antibiotics reduced the relative risk of wound infection by 81% with an absolute risk reduction of 8%.⁴²

A modifiable risk factor for acute kidney injury is the specific antibiotic used for prophylaxis. Multiple studies assessed the risk of acute kidney injury comparing regimens containing an aminoglycoside (typically gentamicin) with regimens lacking these agents.^20–26 In general, these studies found a significantly higher risk of acute kidney injury when gentamicin was used.

Challagundla et al²⁴ found an incidence of acute kidney injury of 52% using RIFLE creatinine criteria in 52 patients receiving 8 g total of flucloxacillin plus 160 mg of gentamicin (120 mg if they weighed less than 60 kg) compared with 8% in 48 patients given cefuroxime (3 g total) and 14% in an additional 52 patients also given cefuroxime.

Johansson et al²⁵ found an incidence of KDIGO creatinine-based acute kidney injury of 13% in 70 patients given dicloxacillin alone prophylactically compared with 27% given dicloxacillin and gentamicin, with a relative risk of 3.

Bell et al,²¹ in a large registry-based analysis from Scotland involving 7,666 elective orthopedic procedures, found that use of flucloxacillin 2 g plus a single dose of gentamicin 4 mg/kg was significantly associated with a 94% higher risk of acute kidney injury (KDIGO creatinine criteria) compared with a cefuroxime-based regimen, with absolute rates increasing from 6.2% to 10.8%.

Dubrovskaya et al²⁰ and Ferguson et al,²⁶ in contrast, found no increased risk with addition of gentamicin.

We recommend avoiding aminoglycosides for prophylaxis in primary lower-extremity total joint arthroplasty in patients at higher risk unless required for specific microbiologic reasons.

Vancomycin may also increase risk

Courtney et al¹⁹ assessed the risk of adding vancomycin to cefazolin for routine prophylaxis in a retrospective series of 1,828 total hip or knee arthroplasties and found a significantly higher rate of acute kidney injury, using AKIN criteria (13% vs 8%, odds ratio by multivariate analysis 1.82, P = .002).¹⁹

Other agents shown to be effective in treating periprosthetic joint infections or complicated skin and soft-tissue infections with resistant organisms include daptomycin⁴³ and linezolid.⁴⁴ These nonnephrotoxic alternatives to vancomycin may be a consideration if prophylaxis for methicillin-resistant Staphylococcus aureus is deemed necessary in patients at risk for acute kidney injury.

Deep infection may complicate nearly 1% of total hip⁴⁵ and 2% of total knee arthroplasties.⁴⁶ Kurtz et al^4,6 have projected that by 2030, infection will be the cause of two-thirds of the estimated 268,000 revision total knee arthroplasties and about half of the estimated 96,700 revision total hip arthroplasties.

The most common method of treating a chronically infected replacement joint is a 2-stage procedure.⁵ First, the prosthesis is removed, all infected bone and soft tissue is debrided, and an antibiotic-loaded cement spacer is implanted. Systemic antibiotics are given concurrently, typically for about 6 weeks. After the infection is brought under control, perhaps 2 to 3 months later, the spacer is removed and a new joint is implanted with antibiotic-loaded cement. A 1-stage procedure may be an option in selected cases and would obviate the need for an antibiotic-loaded cement spacer.^47,48

Of obvious relevance to development of acute kidney injury is the choice and amount of antibiotics embedded in the cement used for spacers and in implantation. Very high antibiotic levels are achieved within the joint space, usually with little systemic absorption, although significant systemic exposure has been documented in some cases.

The polymethylmethacrylate cement used for these purposes comes in 40-g bags. Multiple bags are typically required per joint, perhaps 2 to 4.⁴⁹

The rate of elution of antibiotics is determined by several factors, including surface area, porosity, and the number of antibiotics. In general, elution is greatest early on, with exponential decline lasting perhaps 1 week,  followed by slow, sustained release over weeks to months.⁵⁰ However, several in vitro studies have indicated that only about 5%^50,51 of the total antibiotic actually elutes over time.

Initially, multiple antibiotic-laden cement beads were used to fill the joint space, but this significantly limited function and mobility.⁵² Now, cement spacers are used, and they can be nonarticulating or articulating for maximal joint mobility.⁵³ Although much greater antibiotic elution occurs from beads due to their high surface area-to-volume ratio, spacers still provide an adequate dose.

ANTIBIOTIC-LOADED CEMENT: DOSAGE AND ELUTION CHARACTERISTICS

Antibiotic-loaded cement can be either low-dose or high-dose.

Low-dose cement

Low-dose cement typically consists of 0.5 to 1.0 g of antibiotic per 40-g bag of cement, usually an aminoglycoside (gentamicin or tobramycin) or vancomycin, and can be purchased premixed by the manufacturer. Such cement is only used prophylactically with primary total joint arthroplasty or revision for aseptic reasons, a practice common in Europe but less so in the United States. Some American authors propose antibiotic-loaded cement prophylaxis for patients at high risk, eg, those with immunosuppression, inflammatory cause of arthritis, or diabetes.⁵⁴

Vrabec et al,⁵⁵ in a study of low-dose tobramycin-loaded cement used for primary total knee arthroplasty, found a peak median intra-articular tobramycin concentration of 32 mg/L at 6 hours, declining to 6 mg/L at 48 hours with all serum levels 0.3 mg/L or less (unmeasureable) at similar time points.

Sterling et al,⁵⁶ studying primary total hip arthroplasties with low-dose tobramycin-loaded cement, found mean levels in drainage fluid of 103 mg/L at 6 hours, declining to 15 mg/L at 48 hours. Serum levels peaked at 0.94 mg/L at 3 hours, declining to 0.2 mg/L by 48 hours.

Although most of the antibiotic elution occurs early (within the first week), antibiotic can be found in joint aspirates up to 20 years later.⁵⁷ We are unaware of any well-documented cases of acute kidney injury ascribable to low-dose antibiotic-loaded cement used prophylactically. One case report making this assertion did not determine serum levels of aminoglycoside.⁵⁸

High-dose cement

High-dose antibiotic-loaded cement typically contains about 4 to 8 g of antibiotic per 40-g bag of cement and is used in the treatment of prosthetic joint infection to form the spacers. The antibiotic must be mixed into the cement powder by the surgeon in the operating room.

There is no standard combination or dosage. The choice of antibiotic can be tailored to the infecting organism if known. Otherwise, gram-positive organisms are most common, and vancomycin and aminoglycosides are often used together. This particular combination will enhance the elution of both antibiotics when studied in vitro, a process termed “passive opportunism.”⁵⁹ Other antibiotics in use include aztreonam, piperacillin, teicoplanin, fluoroquinolones, cephalosporins, and daptomycin, among others.

About 8 g of antibiotic total per 40-g bag is the maximum to allow easy molding.⁵² As an example, this may include 4 g of vancomycin and 3.6 g of tobramycin per 40 g. Given that 3 to 4 such bags are often used per joint, there is significant risk of systemic exposure.

Kalil et al⁶⁰ studied 8 patients who received high-dose tobramycin-loaded cement to treat periprosthetic joint infections of the hip or knee and found that 7 had detectable serum levels (mean 0.84 mg/L, highest 2.0 mg/L), including 1 with a level of 0.9 mg/L on day 38; 4 of these 8 developed acute kidney injury by AKIN criteria, although other risk factors for acute kidney injury existed. Nearly all had concomitant vancomycin (3 to 8 g) added to the cement as well.

Hsieh et al⁶¹ studied 46 patients with infected total hip arthroplasties treated with high-dose antibiotic-loaded cement spacers (vancomycin 4 g and aztreonam 4 g per 40-g bag) and found vancomycin levels in joint drainage higher than 1,500 mg/L on day 1, decreasing to 571 mg/L on day 7; serum levels were low (range 0.1–1.6 mg/L at 24 hours), falling to undetectable by 72 hours.

Case reports have associated high-dose antibiotic-loaded cement spacers with acute kidney injury.

Curtis et al⁶² described an 85-year-old patient with stage 3 chronic kidney disease who was treated for an infected total knee arthroplasty with an antibiotic-loaded cement spacer (containing 3.6 g of tobramycin and 3 g of cefazolin per 40-g bag, 3 bags total) and developed stage 3 acute kidney injury. After 16 days and 3 hemodialysis sessions, the patient’s serum tobramycin level was still 2 mg/L despite receiving no systemic tobramycin.

Wu et al⁶³ reported a case of acute kidney injury that required dialysis after implantation of a tobramycin- and vancomycin-loaded spacer, with persistent serum tobramycin levels despite repeated hemodialysis sessions until the spacer was removed.

Chalmers et al⁶⁴ described 2 patients with acute kidney injury and persistently elevated serum tobramycin levels (3.9 mg/L on day 39 in 1 patient and 2.0 mg/L on day 24 in the other patient) despite no systemic administration.

In these and other case reports,^65–67 dialysis and spacer explantation were usually required. 


Comment. It is intuitive that acute kidney injury would more likely complicate revision total joint arthroplasties for infection than for primary total joint arthroplasties or revisions for aseptic reasons, given the systemic effects of infection and exposure to nephrotoxic or allergenic antibiotics. And the available data suggest that the risk of acute kidney injury is higher with revision for prosthetic joint infection than with revision for aseptic reasons. However, many of the studies were retrospective, relatively small, single-center series and used different definitions of acute kidney injury.

Luu et al⁸³ performed a systematic review of studies published between January 1989 and June 2012 reporting systemic complications (including acute kidney injury) of 2-stage revision arthroplasties including placement of an antibiotic-loaded cement spacer for treatment of periprosthetic joint infection. Overall, 10 studies were identified with 544 total patients. Five of these studies, with 409 patients, reported at least 1 case of acute kidney injury for a total of 27 patients, giving an incidence of 6.6% in these studies.^68–71 The remaining 5 studies, totaling 135 patients, did not report any cases of acute kidney injury,^{50,61,76–78} although that was not the primary focus of any of those trials.

Most notable from this systematic review, the study of Menge et al⁶⁹ retrospectively determined the incidence of acute kidney injury (defined as a 50% rise in serum creatinine to > 1.4 mg/dL within 90 days of surgery) to be 17% in 84 patients with infected total knee arthroplasties treated with antibiotic-loaded cement spacers. A mean of 3.5 bags of cement per spacer were used in the 35 articulating spacers, compared with 2.9 per nonarticulating spacer. These spacers contained vancomycin in 82% (median 4.0 g, range 1–16 g) and tobramycin in 94% (median 4.8 g, range 1–12 g), among others in small percentages. The dose of tobramycin in the spacer considered either as a dichotomous variable (> 4.8 g, OR 5.87) or linearly (OR 1.24 per 1-g increase) was significantly associated with acute kidney injury, although systemic administration of aminoglycosides or vancomycin was not.

Additional single-center series that were published subsequent to this review have generally used more current diagnostic criteria.

Noto et al⁷² found that 10 of 46 patients treated with antibiotic-loaded cement spacers had a greater than 50% rise in serum creatinine (average increase 260%). All spacers contained tobramycin (mean dose 8.2 g), and 9 of 10 also contained vancomycin (mean 7.6 g). All of the 9 patients with acute kidney injury with follow-up data recovered renal function.

Reed et al⁷⁵ found 26 cases of acute kidney injury (based on RIFLE creatinine criteria) in 306 patients with antibiotic-loaded cement spacers treating various periprosthetic joint infections (including hips, knees, shoulders, and digits) and compared them with 74 controls who did not develop acute kidney injury. By multivariable analysis, receipt of an ACE inhibitor within 7 days of surgery and receipt of piperacillin-tazobactam within 7 days after surgery were both significantly more common in cases with acute kidney injury than in controls without acute kidney injury.

Aeng et al⁷³ prospectively studied 50 consecutive patients receiving antibiotic-loaded spacers containing tobramycin (with or without vancomycin) for treatment of infected hip or knee replacements. Using RIFLE creatinine criteria, they found an incidence of acute kidney injury of 20% (10 of 50). Factors significantly associated with acute kidney injury included cement premixed by the manufacturer with gentamicin (0.5 g per 40-g bag) in addition to the tobramycin they added, intraoperative blood transfusions, and postoperative use of nonsteroidal anti-inflammatory drugs.

Geller et al,⁷⁴ in a multicenter retrospective study of 247 patients with prosthetic joint infections (156 knees and 91 hips) undergoing antibiotic-loaded cement spacer placement, found an incidence of acute kidney injury of 26% based on KDIGO creatinine criteria. Significant risk factors included higher body mass index, lower preoperative hemoglobin level, drop in hemoglobin after surgery, and comorbidity (hypertension, diabetes, chronic kidney disease, or cardiovascular disease). Most of the spacers contained a combination of vancomycin and either tobramycin (81%) or gentamicin (13%). The spacers contained an average of 5.3 g (range 0.6–18 g) of vancomycin (average 2.65 g per 40-g bag) and an average of 5.2 g (range 0.5–16.4 g) of tobramycin (average 2.6 g per bag).

As in Menge et al,⁶⁹ this study illustrates the wide range of antibiotic dosages in use and the lack of standardization. In contrast to the study by Menge et al, however, development of acute kidney injury was not related to the amount of vancomycin or tobramycin contained in the spacers. Eventual clearance of infection (at 1 and 2 years) was significantly related to increasing amounts of vancomycin. Multiple different systemic antibiotics were used, most commonly vancomycin (44%), and systemic vancomycin was not associated with acute kidney injury.

Yadav et al,⁸¹ in a study of 3,129 consecutive revision procedures of the knee or hip, found an incidence of acute kidney injury by RIFLE creatinine criteria of 29% in the 197 patients who received antibiotic-loaded cement spacers for periprosthetic joint infection compared with 3.4% in the 2,848 who underwent revision for aseptic reasons. In 84 patients with prosthetic joint infection having various surgeries not including placement of a spacer, the acute kidney injury rate at some point in their course was an alarmingly high 82%. In the group that received spacers, only age and comorbidity as assessed by Charlson comorbidity index were independently associated with acute kidney injury by multivariate analysis. Surprisingly, modest renal impairment was protective, possibly because physicians of patients with chronic kidney disease were more vigilant and took appropriate measures to prevent acute kidney injury.

Overall, the risk of acute kidney injury appears to be much higher during treatment of prosthetic joint infection with a 2-stage procedure using an antibiotic-loaded cement spacer than after primary total joint arthroplasty or revision for aseptic reasons, and may complicate up to one-third of cases.

As in primary total joint arthroplasty in general, higher-risk cases should be identified based on age, body mass index, chronic kidney disease, comorbidities (hypertension, diabetes, established cardiovascular disease), and anemia.

Preoperative transfusion can be considered case by case depending on degree of anemia and associated risk factors.

All renin-angiotensin-aldosterone system inhibitors should be withheld starting 1 week before surgery.

Both nonselective and cyclooxygenase-2 selective nonsteroidal anti-inflammatory drugs should be avoided, if possible.

Strict attention should be paid to adequate intraoperative and postoperative fluid resuscitation.

Kidney function should be monitored closely in the early postoperative period, including urine output and daily creatinine for at least 72 hours.

Systemic administration of potentially nephrotoxic antibiotics should be minimized, especially the combination of vancomycin with piperacillin-tazobactam.⁸⁴ Daptomycin is a consideration.⁴³

If acute kidney injury should develop, serum levels of vancomycin or aminoglycosides should be measured if the spacer contains these antibiotics. The spacer may need to be removed if toxic serum levels persist.

TAKE-HOME POINTS

Acute kidney injury may complicate up to 10% of primary lower-extremity total joint arthroplasties and up to 25% of periprosthetic joint infections treated with a 2-stage procedure including placement of an antibiotic-loaded cement spacer in the first stage.

Risk factors for acute kidney injury include older age, obesity, chronic kidney disease, and overall comorbidity. Potentially modifiable risk factors include anemia, perioperative transfusions, aminoglycoside prophylaxis, perioperative renin-angiotensin system blockade, and postoperative nonsteroidal anti-inflammatory drugs. These should be mitigated when possible.

In patients with periprosthetic joint infection who receive antibiotic-loaded cement spacers, especially patients  with additional risk factors for acute kidney injury, strict attention should be paid to the dose of antibiotic in the spacer, with levels checked postoperatively if necessary. Nonnephrotoxic antibiotics should be chosen for systemic administration when possible.

Prospective randomized controlled trials are needed to guide therapy after total joint arthroplasty, and to verify the adverse long-term outcomes of acute kidney injury in this setting.

Total hip or knee replacement (also called total joint arthroplasty) is highly successful at relieving pain and restoring function, but at the risk of acute kidney injury, which is a sudden loss of renal function. Various factors have been associated with this risk, some of which are potentially modifiable, notably, the use of nephrotoxic antibiotics and other drugs.

This review examines the incidence of acute kidney injury using current criteria in total joint arthroplasty of the hip or knee in general, and in the setting of revision surgery for prosthetic joint infection in particular, in which the risk is higher. We identify risk factors for acute kidney injury and propose ways to lower the risk.

MILLIONS OF PROCEDURES ANNUALLY

Total replacement of the hip^1,2 or knee³ is being done more and more. Kurtz et al⁴ estimate that by the year 2030, we will see approximately 3.5 million primary total knee and 500,000 primary total hip replacements every year. In addition, revision total knee procedures are expected to exceed 250,000 per year, and revision total hip procedures are expected to exceed 90,000 per year.⁴

Chronic infection may complicate up to 2% of these procedures and is associated with significant morbidity, death, and financial costs. Currently, it may be the reason for 25% of total joint arthroplasty revisions,⁵ but by the year 2030, it is projected to account for 66% of revision total knee arthroplasties and 48% of revision total hip arthroplasties.⁶

PRIMARY TOTAL JOINT ARTHROPLASTY AND ACUTE KIDNEY INJURY

Study designs, findings varied widely

The incidence of acute kidney injury varied markedly among the studies of primary total joint arthroplasty or revision for aseptic reasons. Numerous factors explain this heterogeneity.

Designs ranged from single-center studies with relatively small numbers of patients to large regional and national samples based on administrative data.

Almost all of the studies were retrospective. We are not aware of any randomized controlled trials.

Discharge diagnosis may miss many cases

Several studies based the diagnosis of acute kidney injury on International Classification of Diseases, Ninth Revision (ICD-9) coding from hospital discharge summaries.

Nadkarni et al,²⁹ in the largest study published to date, used the nationwide inpatient sample database of more than 7 million total joint arthroplasties and found an incidence of acute kidney injury based on ICD-9 coding of 1.3% over the years 2002 to 2012, although this increased to 1.8% to 1.9% from 2010 to 2012.

Lopez-de-Andres et al,³⁰ in a similar study using the Spanish national hospital discharge database, evaluated 20,188 patients who underwent revision total hip or knee arthroplasty and found an overall incidence of acute kidney injury of 0.94%, also using ICD-9 coding.

Gharaibeh et al³¹ used similar methods to diagnose acute kidney injury in a single-center study of 8,949 patients and found an incidence of 1.1%.

Although these 3 studies suggest that the incidence of acute kidney injury is relatively low, Grams et al³⁵ found the sensitivity of ICD-9 coding from hospital records for the diagnosis of acute kidney injury to be only 11.7% compared with KDIGO serum creatinine and urine output criteria. This suggests that the true incidence in these studies may be many times higher, possibly near 10%.

Do all stages of kidney injury count?

Jafari et al,⁷ in a large series from a single medical center, used only the “I” (injury) and “F” (failure) levels of the RIFLE criteria (corresponding to stages 2 and 3 of the KDIGO criteria) and found an incidence of 0.55% in more than 17,000 total joint arthroplasties.

Jamsa et al⁸ used the same criteria for acute kidney injury (only “I” and “F”) and found 58 cases in 5,609 patients in whom postoperative serum creatinine was measured, for an incidence of 1%; the remaining 14,966 patients in their cohort did not have serum creatinine measured, and it was assumed they did not have acute kidney injury. Neither of these studies included the most common “R” (risk) stage of acute kidney injury.

Parr et al³⁶ recently studied a nationwide sample of 657,840 hospitalized veterans and found that of 90,614 who developed acute kidney injury based on KDIGO creatinine criteria, 84% reached only stage R. This suggests that if all stages were considered, the true incidence of acute kidney injury would have been higher—possibly 4% in the Jafari series and possibly 7% in the Jamsa series.

Smaller studies had higher rates

Smaller, single-center series reported much higher incidences of acute kidney injury.

Kimmel et al¹¹ found an incidence of 14.8% in 425 total joint arthroplasties using RIFLE creatinine criteria.

Johansson et al²⁵ found an incidence of 19.9% in 136 total joint arthroplasties using KDIGO creatinine criteria.

Sehgal et al⁹ found an incidence of 21.9% in 659 total joint arthroplasties using AKIN creatinine criteria.

Challagundla et al²⁴ found an incidence of 23.7% in 198 procedures using RIFLE creatinine criteria.

Weingarten et al,¹⁰ in a single-center series of 7,463 total joint arthroplasties, found an incidence of acute kidney injury of only 2.2% using AKIN criteria, although 12% of the patients with acute kidney injury did not return to their baseline serum creatinine levels by 3 months.

Our estimate: Nearly 10%

In total, in the 20 studies in Table 1 that included all stages of acute kidney injury, there were 1,909 cases of acute kidney injury in 34,337 patients, for an incidence of 5.6%. Considering that all studies but one were retrospective and none considered urine output criteria for acute kidney injury, we believe that using current KDIGO criteria, the true incidence of acute kidney injury complicating primary lower-extremity total joint arthroplasties is really closer to 10%.

Various factors have been associated with development of acute kidney injury by multivariate analysis in these studies. Some are modifiable, while others are not, at least in the short term.

Nonmodifiable risk factors

Older age is often significant in studies assessing primary total joint arthroplasty or revision total joint arthroplasty not specifically for infection.^{11,12,16,17,26,28}

Obesity is also a major factor in the development of acute kidney injury,^{7,10–12,17,18} and, along with age, is a major factor contributing to the need for joint replacement in the first place.

Male sex may increase risk.²⁹

Diabetes mellitus was identified as a risk factor in several studies,^10,12,17,20 and hypertension in a few.^7,10,24

Other comorbidities and factors such as cardiovascular disease,^7,10 liver disease,⁷ pulmonary disease,⁷ high American Society of Anesthesiology score,^8,19 and benign heart murmurs preoperatively by routine physical examination have also been linked to acute kidney injury after joint arthroplasty.²⁸

Chronic kidney disease as a risk factor

Chronic kidney disease at baseline was associated with acute kidney injury in several of these series.^{7,11–13,15,19,29}

Warth et al¹² studied 1,038 patients and found an incidence of acute kidney injury of 11% in the 135 with chronic kidney disease (defined as serum creatinine > 1.2 mg/dL) and who received acetaminophen or narcotics for pain control, compared with 4.8% in the remaining 903 patients without chronic kidney disease, who received ketorolac or celecoxib.

Perregaard et al¹³ studied 3,410 patients who underwent total hip arthroplasty and found an incidence of acute kidney injury (per KDIGO creatinine criteria) of 2.2% overall, but 7% in the 134 patients with chronic kidney disease based on KDIGO creatinine criteria.

Nowicka et al¹⁵ found an incidence of acute kidney injury of 16.7% in the 48 patients with chronic kidney disease (defined as a glomerular filtration rate estimated by the Cockroft-Gault formula of less than 60 mL/min/1.73 m²), compared with 4.5% in the remaining 289.

Modifiable risk factors

Modifiable risk factors that should be considered in high-risk cases include anemia, perioperative blood transfusion, perioperative use of renin-angiotensin-aldosterone system inhibitors such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), particular antibiotics used for prophylaxis, and nonsteroidal anti-inflammatory drugs used postoperatively.

Anemia and blood transfusion

Preoperative anemia has been associated with postoperative acute kidney injury in various surgical settings such as cardiac surgery.^37,38 Perioperative red blood cell transfusions have also been associated with acute kidney injury in cardiac surgery; similar results may apply to total joint arthroplasty.

Choi et al,¹⁷ in 2,467 patients undergoing hip replacement, found a significant risk for acute kidney injury if postoperative hemoglobin was consistently below 10 g/dL compared with consistently above this level, with an inverse probability-of-treatment weighted odds ratio of 1.817 (P = .011).

Others have found a significant association of perioperative blood transfusion with acute kidney injury in total joint arthroplasty.^10,29

Nadkarni et al,²⁹ for example, used the nationwide inpatient sample database and found by multivariate analysis that perioperative blood transfusion was strongly associated with acute kidney injury, with an adjusted odds ratio of 2.28 (95% confidence interval [CI] 2.15–2.42, P < .0001).

Comment. A higher incidence of acute kidney injury may represent confounding by indication bias, as sicker patients or complicated surgeries may require transfusion, and this risk may not be completely accounted for by multivariate analysis. It is also possible, however, that transfusions per se may contribute to acute kidney injury. Possible direct or indirect mechanisms mediating acute kidney injury include hemolytic reactions, circulatory overload, acute lung injury, and immunomodulatory effects.³⁹

Preoperative transfusion in anemic patients undergoing cardiac surgery may also reduce the incidence of postoperative acute kidney injury both by correcting the anemia and by limiting the need for perioperative transfusions.⁴⁰ It remains to be determined whether elective preoperative transfusion to correct anemia would reduce postoperative development of acute kidney injury in total joint arthroplasty. As an aside, perioperative transfusion has also been linked to development of periprosthetic joint infection.⁴¹

Renin-angiotensin-aldosterone system inhibitors

Several studies found perioperative use of renin-angiotensin-aldosterone system inhibitors to be a risk factor for acute kidney injury.

Kimmel et al¹¹ reported adjusted odds ratios of 2.70 (95% CI 1.12–6.48) for ACE inhibitor use and 2.64 (95% CI 1.18–5.93) for ARB use in a study of 425 primary total joint arthroplasties.

Challagundla et al²⁴ found an odds ratio of 3.07 (95% CI 1.40–6.74) with ACE inhibitor or ARB use by multivariate analysis in 198 total joint arthroplasties.

Nielson et al¹⁸ studied 798 patients who underwent total joint arthroplasty and found that preoperative use of renin-angiotensin system inhibitors was associated with a significantly higher rate of postoperative acute kidney injury (8.3% vs 1.7% without inhibition), which was statistically significant by multivariate analysis (odds ratio 2.6, 95% CI 1.04–6.51).

We recommend holding renin-angiotensin-aldosterone system inhibitors 7 days before surgery through the postoperative period in high-risk cases.

Aminoglycoside use as a risk factor

Prophylactic administration of systemic antibiotics is the standard of care. In a systematic review of 26 studies and meta-analysis of 7 studies (3,065 patients), prophylactic antibiotics reduced the relative risk of wound infection by 81% with an absolute risk reduction of 8%.⁴²

A modifiable risk factor for acute kidney injury is the specific antibiotic used for prophylaxis. Multiple studies assessed the risk of acute kidney injury comparing regimens containing an aminoglycoside (typically gentamicin) with regimens lacking these agents.^20–26 In general, these studies found a significantly higher risk of acute kidney injury when gentamicin was used.

Challagundla et al²⁴ found an incidence of acute kidney injury of 52% using RIFLE creatinine criteria in 52 patients receiving 8 g total of flucloxacillin plus 160 mg of gentamicin (120 mg if they weighed less than 60 kg) compared with 8% in 48 patients given cefuroxime (3 g total) and 14% in an additional 52 patients also given cefuroxime.

Johansson et al²⁵ found an incidence of KDIGO creatinine-based acute kidney injury of 13% in 70 patients given dicloxacillin alone prophylactically compared with 27% given dicloxacillin and gentamicin, with a relative risk of 3.

Bell et al,²¹ in a large registry-based analysis from Scotland involving 7,666 elective orthopedic procedures, found that use of flucloxacillin 2 g plus a single dose of gentamicin 4 mg/kg was significantly associated with a 94% higher risk of acute kidney injury (KDIGO creatinine criteria) compared with a cefuroxime-based regimen, with absolute rates increasing from 6.2% to 10.8%.

Dubrovskaya et al²⁰ and Ferguson et al,²⁶ in contrast, found no increased risk with addition of gentamicin.

We recommend avoiding aminoglycosides for prophylaxis in primary lower-extremity total joint arthroplasty in patients at higher risk unless required for specific microbiologic reasons.

Vancomycin may also increase risk

Courtney et al¹⁹ assessed the risk of adding vancomycin to cefazolin for routine prophylaxis in a retrospective series of 1,828 total hip or knee arthroplasties and found a significantly higher rate of acute kidney injury, using AKIN criteria (13% vs 8%, odds ratio by multivariate analysis 1.82, P = .002).¹⁹

Other agents shown to be effective in treating periprosthetic joint infections or complicated skin and soft-tissue infections with resistant organisms include daptomycin⁴³ and linezolid.⁴⁴ These nonnephrotoxic alternatives to vancomycin may be a consideration if prophylaxis for methicillin-resistant Staphylococcus aureus is deemed necessary in patients at risk for acute kidney injury.

Deep infection may complicate nearly 1% of total hip⁴⁵ and 2% of total knee arthroplasties.⁴⁶ Kurtz et al^4,6 have projected that by 2030, infection will be the cause of two-thirds of the estimated 268,000 revision total knee arthroplasties and about half of the estimated 96,700 revision total hip arthroplasties.

The most common method of treating a chronically infected replacement joint is a 2-stage procedure.⁵ First, the prosthesis is removed, all infected bone and soft tissue is debrided, and an antibiotic-loaded cement spacer is implanted. Systemic antibiotics are given concurrently, typically for about 6 weeks. After the infection is brought under control, perhaps 2 to 3 months later, the spacer is removed and a new joint is implanted with antibiotic-loaded cement. A 1-stage procedure may be an option in selected cases and would obviate the need for an antibiotic-loaded cement spacer.^47,48

Of obvious relevance to development of acute kidney injury is the choice and amount of antibiotics embedded in the cement used for spacers and in implantation. Very high antibiotic levels are achieved within the joint space, usually with little systemic absorption, although significant systemic exposure has been documented in some cases.

The polymethylmethacrylate cement used for these purposes comes in 40-g bags. Multiple bags are typically required per joint, perhaps 2 to 4.⁴⁹

The rate of elution of antibiotics is determined by several factors, including surface area, porosity, and the number of antibiotics. In general, elution is greatest early on, with exponential decline lasting perhaps 1 week,  followed by slow, sustained release over weeks to months.⁵⁰ However, several in vitro studies have indicated that only about 5%^50,51 of the total antibiotic actually elutes over time.

Initially, multiple antibiotic-laden cement beads were used to fill the joint space, but this significantly limited function and mobility.⁵² Now, cement spacers are used, and they can be nonarticulating or articulating for maximal joint mobility.⁵³ Although much greater antibiotic elution occurs from beads due to their high surface area-to-volume ratio, spacers still provide an adequate dose.

ANTIBIOTIC-LOADED CEMENT: DOSAGE AND ELUTION CHARACTERISTICS

Antibiotic-loaded cement can be either low-dose or high-dose.

Low-dose cement

Low-dose cement typically consists of 0.5 to 1.0 g of antibiotic per 40-g bag of cement, usually an aminoglycoside (gentamicin or tobramycin) or vancomycin, and can be purchased premixed by the manufacturer. Such cement is only used prophylactically with primary total joint arthroplasty or revision for aseptic reasons, a practice common in Europe but less so in the United States. Some American authors propose antibiotic-loaded cement prophylaxis for patients at high risk, eg, those with immunosuppression, inflammatory cause of arthritis, or diabetes.⁵⁴

Vrabec et al,⁵⁵ in a study of low-dose tobramycin-loaded cement used for primary total knee arthroplasty, found a peak median intra-articular tobramycin concentration of 32 mg/L at 6 hours, declining to 6 mg/L at 48 hours with all serum levels 0.3 mg/L or less (unmeasureable) at similar time points.

Sterling et al,⁵⁶ studying primary total hip arthroplasties with low-dose tobramycin-loaded cement, found mean levels in drainage fluid of 103 mg/L at 6 hours, declining to 15 mg/L at 48 hours. Serum levels peaked at 0.94 mg/L at 3 hours, declining to 0.2 mg/L by 48 hours.

Although most of the antibiotic elution occurs early (within the first week), antibiotic can be found in joint aspirates up to 20 years later.⁵⁷ We are unaware of any well-documented cases of acute kidney injury ascribable to low-dose antibiotic-loaded cement used prophylactically. One case report making this assertion did not determine serum levels of aminoglycoside.⁵⁸

High-dose cement

High-dose antibiotic-loaded cement typically contains about 4 to 8 g of antibiotic per 40-g bag of cement and is used in the treatment of prosthetic joint infection to form the spacers. The antibiotic must be mixed into the cement powder by the surgeon in the operating room.

There is no standard combination or dosage. The choice of antibiotic can be tailored to the infecting organism if known. Otherwise, gram-positive organisms are most common, and vancomycin and aminoglycosides are often used together. This particular combination will enhance the elution of both antibiotics when studied in vitro, a process termed “passive opportunism.”⁵⁹ Other antibiotics in use include aztreonam, piperacillin, teicoplanin, fluoroquinolones, cephalosporins, and daptomycin, among others.

About 8 g of antibiotic total per 40-g bag is the maximum to allow easy molding.⁵² As an example, this may include 4 g of vancomycin and 3.6 g of tobramycin per 40 g. Given that 3 to 4 such bags are often used per joint, there is significant risk of systemic exposure.

Kalil et al⁶⁰ studied 8 patients who received high-dose tobramycin-loaded cement to treat periprosthetic joint infections of the hip or knee and found that 7 had detectable serum levels (mean 0.84 mg/L, highest 2.0 mg/L), including 1 with a level of 0.9 mg/L on day 38; 4 of these 8 developed acute kidney injury by AKIN criteria, although other risk factors for acute kidney injury existed. Nearly all had concomitant vancomycin (3 to 8 g) added to the cement as well.

Hsieh et al⁶¹ studied 46 patients with infected total hip arthroplasties treated with high-dose antibiotic-loaded cement spacers (vancomycin 4 g and aztreonam 4 g per 40-g bag) and found vancomycin levels in joint drainage higher than 1,500 mg/L on day 1, decreasing to 571 mg/L on day 7; serum levels were low (range 0.1–1.6 mg/L at 24 hours), falling to undetectable by 72 hours.

Case reports have associated high-dose antibiotic-loaded cement spacers with acute kidney injury.

Curtis et al⁶² described an 85-year-old patient with stage 3 chronic kidney disease who was treated for an infected total knee arthroplasty with an antibiotic-loaded cement spacer (containing 3.6 g of tobramycin and 3 g of cefazolin per 40-g bag, 3 bags total) and developed stage 3 acute kidney injury. After 16 days and 3 hemodialysis sessions, the patient’s serum tobramycin level was still 2 mg/L despite receiving no systemic tobramycin.

Wu et al⁶³ reported a case of acute kidney injury that required dialysis after implantation of a tobramycin- and vancomycin-loaded spacer, with persistent serum tobramycin levels despite repeated hemodialysis sessions until the spacer was removed.

Chalmers et al⁶⁴ described 2 patients with acute kidney injury and persistently elevated serum tobramycin levels (3.9 mg/L on day 39 in 1 patient and 2.0 mg/L on day 24 in the other patient) despite no systemic administration.

In these and other case reports,^65–67 dialysis and spacer explantation were usually required. 


Comment. It is intuitive that acute kidney injury would more likely complicate revision total joint arthroplasties for infection than for primary total joint arthroplasties or revisions for aseptic reasons, given the systemic effects of infection and exposure to nephrotoxic or allergenic antibiotics. And the available data suggest that the risk of acute kidney injury is higher with revision for prosthetic joint infection than with revision for aseptic reasons. However, many of the studies were retrospective, relatively small, single-center series and used different definitions of acute kidney injury.

Luu et al⁸³ performed a systematic review of studies published between January 1989 and June 2012 reporting systemic complications (including acute kidney injury) of 2-stage revision arthroplasties including placement of an antibiotic-loaded cement spacer for treatment of periprosthetic joint infection. Overall, 10 studies were identified with 544 total patients. Five of these studies, with 409 patients, reported at least 1 case of acute kidney injury for a total of 27 patients, giving an incidence of 6.6% in these studies.^68–71 The remaining 5 studies, totaling 135 patients, did not report any cases of acute kidney injury,^{50,61,76–78} although that was not the primary focus of any of those trials.

Most notable from this systematic review, the study of Menge et al⁶⁹ retrospectively determined the incidence of acute kidney injury (defined as a 50% rise in serum creatinine to > 1.4 mg/dL within 90 days of surgery) to be 17% in 84 patients with infected total knee arthroplasties treated with antibiotic-loaded cement spacers. A mean of 3.5 bags of cement per spacer were used in the 35 articulating spacers, compared with 2.9 per nonarticulating spacer. These spacers contained vancomycin in 82% (median 4.0 g, range 1–16 g) and tobramycin in 94% (median 4.8 g, range 1–12 g), among others in small percentages. The dose of tobramycin in the spacer considered either as a dichotomous variable (> 4.8 g, OR 5.87) or linearly (OR 1.24 per 1-g increase) was significantly associated with acute kidney injury, although systemic administration of aminoglycosides or vancomycin was not.

Additional single-center series that were published subsequent to this review have generally used more current diagnostic criteria.

Noto et al⁷² found that 10 of 46 patients treated with antibiotic-loaded cement spacers had a greater than 50% rise in serum creatinine (average increase 260%). All spacers contained tobramycin (mean dose 8.2 g), and 9 of 10 also contained vancomycin (mean 7.6 g). All of the 9 patients with acute kidney injury with follow-up data recovered renal function.

Reed et al⁷⁵ found 26 cases of acute kidney injury (based on RIFLE creatinine criteria) in 306 patients with antibiotic-loaded cement spacers treating various periprosthetic joint infections (including hips, knees, shoulders, and digits) and compared them with 74 controls who did not develop acute kidney injury. By multivariable analysis, receipt of an ACE inhibitor within 7 days of surgery and receipt of piperacillin-tazobactam within 7 days after surgery were both significantly more common in cases with acute kidney injury than in controls without acute kidney injury.

Aeng et al⁷³ prospectively studied 50 consecutive patients receiving antibiotic-loaded spacers containing tobramycin (with or without vancomycin) for treatment of infected hip or knee replacements. Using RIFLE creatinine criteria, they found an incidence of acute kidney injury of 20% (10 of 50). Factors significantly associated with acute kidney injury included cement premixed by the manufacturer with gentamicin (0.5 g per 40-g bag) in addition to the tobramycin they added, intraoperative blood transfusions, and postoperative use of nonsteroidal anti-inflammatory drugs.

Geller et al,⁷⁴ in a multicenter retrospective study of 247 patients with prosthetic joint infections (156 knees and 91 hips) undergoing antibiotic-loaded cement spacer placement, found an incidence of acute kidney injury of 26% based on KDIGO creatinine criteria. Significant risk factors included higher body mass index, lower preoperative hemoglobin level, drop in hemoglobin after surgery, and comorbidity (hypertension, diabetes, chronic kidney disease, or cardiovascular disease). Most of the spacers contained a combination of vancomycin and either tobramycin (81%) or gentamicin (13%). The spacers contained an average of 5.3 g (range 0.6–18 g) of vancomycin (average 2.65 g per 40-g bag) and an average of 5.2 g (range 0.5–16.4 g) of tobramycin (average 2.6 g per bag).

As in Menge et al,⁶⁹ this study illustrates the wide range of antibiotic dosages in use and the lack of standardization. In contrast to the study by Menge et al, however, development of acute kidney injury was not related to the amount of vancomycin or tobramycin contained in the spacers. Eventual clearance of infection (at 1 and 2 years) was significantly related to increasing amounts of vancomycin. Multiple different systemic antibiotics were used, most commonly vancomycin (44%), and systemic vancomycin was not associated with acute kidney injury.

Yadav et al,⁸¹ in a study of 3,129 consecutive revision procedures of the knee or hip, found an incidence of acute kidney injury by RIFLE creatinine criteria of 29% in the 197 patients who received antibiotic-loaded cement spacers for periprosthetic joint infection compared with 3.4% in the 2,848 who underwent revision for aseptic reasons. In 84 patients with prosthetic joint infection having various surgeries not including placement of a spacer, the acute kidney injury rate at some point in their course was an alarmingly high 82%. In the group that received spacers, only age and comorbidity as assessed by Charlson comorbidity index were independently associated with acute kidney injury by multivariate analysis. Surprisingly, modest renal impairment was protective, possibly because physicians of patients with chronic kidney disease were more vigilant and took appropriate measures to prevent acute kidney injury.

Overall, the risk of acute kidney injury appears to be much higher during treatment of prosthetic joint infection with a 2-stage procedure using an antibiotic-loaded cement spacer than after primary total joint arthroplasty or revision for aseptic reasons, and may complicate up to one-third of cases.

As in primary total joint arthroplasty in general, higher-risk cases should be identified based on age, body mass index, chronic kidney disease, comorbidities (hypertension, diabetes, established cardiovascular disease), and anemia.

Preoperative transfusion can be considered case by case depending on degree of anemia and associated risk factors.

All renin-angiotensin-aldosterone system inhibitors should be withheld starting 1 week before surgery.

Both nonselective and cyclooxygenase-2 selective nonsteroidal anti-inflammatory drugs should be avoided, if possible.

Strict attention should be paid to adequate intraoperative and postoperative fluid resuscitation.

Kidney function should be monitored closely in the early postoperative period, including urine output and daily creatinine for at least 72 hours.

Systemic administration of potentially nephrotoxic antibiotics should be minimized, especially the combination of vancomycin with piperacillin-tazobactam.⁸⁴ Daptomycin is a consideration.⁴³

If acute kidney injury should develop, serum levels of vancomycin or aminoglycosides should be measured if the spacer contains these antibiotics. The spacer may need to be removed if toxic serum levels persist.

TAKE-HOME POINTS

Acute kidney injury may complicate up to 10% of primary lower-extremity total joint arthroplasties and up to 25% of periprosthetic joint infections treated with a 2-stage procedure including placement of an antibiotic-loaded cement spacer in the first stage.

Risk factors for acute kidney injury include older age, obesity, chronic kidney disease, and overall comorbidity. Potentially modifiable risk factors include anemia, perioperative transfusions, aminoglycoside prophylaxis, perioperative renin-angiotensin system blockade, and postoperative nonsteroidal anti-inflammatory drugs. These should be mitigated when possible.

In patients with periprosthetic joint infection who receive antibiotic-loaded cement spacers, especially patients  with additional risk factors for acute kidney injury, strict attention should be paid to the dose of antibiotic in the spacer, with levels checked postoperatively if necessary. Nonnephrotoxic antibiotics should be chosen for systemic administration when possible.

Prospective randomized controlled trials are needed to guide therapy after total joint arthroplasty, and to verify the adverse long-term outcomes of acute kidney injury in this setting.

Total hip or knee replacement (also called total joint arthroplasty) is highly successful at relieving pain and restoring function, but at the risk of acute kidney injury, which is a sudden loss of renal function. Various factors have been associated with this risk, some of which are potentially modifiable, notably, the use of nephrotoxic antibiotics and other drugs.

This review examines the incidence of acute kidney injury using current criteria in total joint arthroplasty of the hip or knee in general, and in the setting of revision surgery for prosthetic joint infection in particular, in which the risk is higher. We identify risk factors for acute kidney injury and propose ways to lower the risk.

MILLIONS OF PROCEDURES ANNUALLY

Total replacement of the hip^1,2 or knee³ is being done more and more. Kurtz et al⁴ estimate that by the year 2030, we will see approximately 3.5 million primary total knee and 500,000 primary total hip replacements every year. In addition, revision total knee procedures are expected to exceed 250,000 per year, and revision total hip procedures are expected to exceed 90,000 per year.⁴

Chronic infection may complicate up to 2% of these procedures and is associated with significant morbidity, death, and financial costs. Currently, it may be the reason for 25% of total joint arthroplasty revisions,⁵ but by the year 2030, it is projected to account for 66% of revision total knee arthroplasties and 48% of revision total hip arthroplasties.⁶

PRIMARY TOTAL JOINT ARTHROPLASTY AND ACUTE KIDNEY INJURY

Study designs, findings varied widely

The incidence of acute kidney injury varied markedly among the studies of primary total joint arthroplasty or revision for aseptic reasons. Numerous factors explain this heterogeneity.

Designs ranged from single-center studies with relatively small numbers of patients to large regional and national samples based on administrative data.

Almost all of the studies were retrospective. We are not aware of any randomized controlled trials.

Discharge diagnosis may miss many cases

Several studies based the diagnosis of acute kidney injury on International Classification of Diseases, Ninth Revision (ICD-9) coding from hospital discharge summaries.

Nadkarni et al,²⁹ in the largest study published to date, used the nationwide inpatient sample database of more than 7 million total joint arthroplasties and found an incidence of acute kidney injury based on ICD-9 coding of 1.3% over the years 2002 to 2012, although this increased to 1.8% to 1.9% from 2010 to 2012.

Lopez-de-Andres et al,³⁰ in a similar study using the Spanish national hospital discharge database, evaluated 20,188 patients who underwent revision total hip or knee arthroplasty and found an overall incidence of acute kidney injury of 0.94%, also using ICD-9 coding.

Gharaibeh et al³¹ used similar methods to diagnose acute kidney injury in a single-center study of 8,949 patients and found an incidence of 1.1%.

Although these 3 studies suggest that the incidence of acute kidney injury is relatively low, Grams et al³⁵ found the sensitivity of ICD-9 coding from hospital records for the diagnosis of acute kidney injury to be only 11.7% compared with KDIGO serum creatinine and urine output criteria. This suggests that the true incidence in these studies may be many times higher, possibly near 10%.

Do all stages of kidney injury count?

Jafari et al,⁷ in a large series from a single medical center, used only the “I” (injury) and “F” (failure) levels of the RIFLE criteria (corresponding to stages 2 and 3 of the KDIGO criteria) and found an incidence of 0.55% in more than 17,000 total joint arthroplasties.

Jamsa et al⁸ used the same criteria for acute kidney injury (only “I” and “F”) and found 58 cases in 5,609 patients in whom postoperative serum creatinine was measured, for an incidence of 1%; the remaining 14,966 patients in their cohort did not have serum creatinine measured, and it was assumed they did not have acute kidney injury. Neither of these studies included the most common “R” (risk) stage of acute kidney injury.

Parr et al³⁶ recently studied a nationwide sample of 657,840 hospitalized veterans and found that of 90,614 who developed acute kidney injury based on KDIGO creatinine criteria, 84% reached only stage R. This suggests that if all stages were considered, the true incidence of acute kidney injury would have been higher—possibly 4% in the Jafari series and possibly 7% in the Jamsa series.

Smaller studies had higher rates

Smaller, single-center series reported much higher incidences of acute kidney injury.

Kimmel et al¹¹ found an incidence of 14.8% in 425 total joint arthroplasties using RIFLE creatinine criteria.

Johansson et al²⁵ found an incidence of 19.9% in 136 total joint arthroplasties using KDIGO creatinine criteria.

Sehgal et al⁹ found an incidence of 21.9% in 659 total joint arthroplasties using AKIN creatinine criteria.

Challagundla et al²⁴ found an incidence of 23.7% in 198 procedures using RIFLE creatinine criteria.

Weingarten et al,¹⁰ in a single-center series of 7,463 total joint arthroplasties, found an incidence of acute kidney injury of only 2.2% using AKIN criteria, although 12% of the patients with acute kidney injury did not return to their baseline serum creatinine levels by 3 months.

Our estimate: Nearly 10%

In total, in the 20 studies in Table 1 that included all stages of acute kidney injury, there were 1,909 cases of acute kidney injury in 34,337 patients, for an incidence of 5.6%. Considering that all studies but one were retrospective and none considered urine output criteria for acute kidney injury, we believe that using current KDIGO criteria, the true incidence of acute kidney injury complicating primary lower-extremity total joint arthroplasties is really closer to 10%.

Various factors have been associated with development of acute kidney injury by multivariate analysis in these studies. Some are modifiable, while others are not, at least in the short term.

Nonmodifiable risk factors

Older age is often significant in studies assessing primary total joint arthroplasty or revision total joint arthroplasty not specifically for infection.^{11,12,16,17,26,28}

Obesity is also a major factor in the development of acute kidney injury,^{7,10–12,17,18} and, along with age, is a major factor contributing to the need for joint replacement in the first place.

Male sex may increase risk.²⁹

Diabetes mellitus was identified as a risk factor in several studies,^10,12,17,20 and hypertension in a few.^7,10,24

Other comorbidities and factors such as cardiovascular disease,^7,10 liver disease,⁷ pulmonary disease,⁷ high American Society of Anesthesiology score,^8,19 and benign heart murmurs preoperatively by routine physical examination have also been linked to acute kidney injury after joint arthroplasty.²⁸

Chronic kidney disease as a risk factor

Chronic kidney disease at baseline was associated with acute kidney injury in several of these series.^{7,11–13,15,19,29}

Warth et al¹² studied 1,038 patients and found an incidence of acute kidney injury of 11% in the 135 with chronic kidney disease (defined as serum creatinine > 1.2 mg/dL) and who received acetaminophen or narcotics for pain control, compared with 4.8% in the remaining 903 patients without chronic kidney disease, who received ketorolac or celecoxib.

Perregaard et al¹³ studied 3,410 patients who underwent total hip arthroplasty and found an incidence of acute kidney injury (per KDIGO creatinine criteria) of 2.2% overall, but 7% in the 134 patients with chronic kidney disease based on KDIGO creatinine criteria.

Nowicka et al¹⁵ found an incidence of acute kidney injury of 16.7% in the 48 patients with chronic kidney disease (defined as a glomerular filtration rate estimated by the Cockroft-Gault formula of less than 60 mL/min/1.73 m²), compared with 4.5% in the remaining 289.

Modifiable risk factors

Modifiable risk factors that should be considered in high-risk cases include anemia, perioperative blood transfusion, perioperative use of renin-angiotensin-aldosterone system inhibitors such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), particular antibiotics used for prophylaxis, and nonsteroidal anti-inflammatory drugs used postoperatively.

Anemia and blood transfusion

Preoperative anemia has been associated with postoperative acute kidney injury in various surgical settings such as cardiac surgery.^37,38 Perioperative red blood cell transfusions have also been associated with acute kidney injury in cardiac surgery; similar results may apply to total joint arthroplasty.

Choi et al,¹⁷ in 2,467 patients undergoing hip replacement, found a significant risk for acute kidney injury if postoperative hemoglobin was consistently below 10 g/dL compared with consistently above this level, with an inverse probability-of-treatment weighted odds ratio of 1.817 (P = .011).

Others have found a significant association of perioperative blood transfusion with acute kidney injury in total joint arthroplasty.^10,29

Nadkarni et al,²⁹ for example, used the nationwide inpatient sample database and found by multivariate analysis that perioperative blood transfusion was strongly associated with acute kidney injury, with an adjusted odds ratio of 2.28 (95% confidence interval [CI] 2.15–2.42, P < .0001).

Comment. A higher incidence of acute kidney injury may represent confounding by indication bias, as sicker patients or complicated surgeries may require transfusion, and this risk may not be completely accounted for by multivariate analysis. It is also possible, however, that transfusions per se may contribute to acute kidney injury. Possible direct or indirect mechanisms mediating acute kidney injury include hemolytic reactions, circulatory overload, acute lung injury, and immunomodulatory effects.³⁹

Preoperative transfusion in anemic patients undergoing cardiac surgery may also reduce the incidence of postoperative acute kidney injury both by correcting the anemia and by limiting the need for perioperative transfusions.⁴⁰ It remains to be determined whether elective preoperative transfusion to correct anemia would reduce postoperative development of acute kidney injury in total joint arthroplasty. As an aside, perioperative transfusion has also been linked to development of periprosthetic joint infection.⁴¹

Renin-angiotensin-aldosterone system inhibitors

Several studies found perioperative use of renin-angiotensin-aldosterone system inhibitors to be a risk factor for acute kidney injury.

Kimmel et al¹¹ reported adjusted odds ratios of 2.70 (95% CI 1.12–6.48) for ACE inhibitor use and 2.64 (95% CI 1.18–5.93) for ARB use in a study of 425 primary total joint arthroplasties.

Challagundla et al²⁴ found an odds ratio of 3.07 (95% CI 1.40–6.74) with ACE inhibitor or ARB use by multivariate analysis in 198 total joint arthroplasties.

Nielson et al¹⁸ studied 798 patients who underwent total joint arthroplasty and found that preoperative use of renin-angiotensin system inhibitors was associated with a significantly higher rate of postoperative acute kidney injury (8.3% vs 1.7% without inhibition), which was statistically significant by multivariate analysis (odds ratio 2.6, 95% CI 1.04–6.51).

We recommend holding renin-angiotensin-aldosterone system inhibitors 7 days before surgery through the postoperative period in high-risk cases.

Aminoglycoside use as a risk factor

Prophylactic administration of systemic antibiotics is the standard of care. In a systematic review of 26 studies and meta-analysis of 7 studies (3,065 patients), prophylactic antibiotics reduced the relative risk of wound infection by 81% with an absolute risk reduction of 8%.⁴²

A modifiable risk factor for acute kidney injury is the specific antibiotic used for prophylaxis. Multiple studies assessed the risk of acute kidney injury comparing regimens containing an aminoglycoside (typically gentamicin) with regimens lacking these agents.^20–26 In general, these studies found a significantly higher risk of acute kidney injury when gentamicin was used.

Challagundla et al²⁴ found an incidence of acute kidney injury of 52% using RIFLE creatinine criteria in 52 patients receiving 8 g total of flucloxacillin plus 160 mg of gentamicin (120 mg if they weighed less than 60 kg) compared with 8% in 48 patients given cefuroxime (3 g total) and 14% in an additional 52 patients also given cefuroxime.

Johansson et al²⁵ found an incidence of KDIGO creatinine-based acute kidney injury of 13% in 70 patients given dicloxacillin alone prophylactically compared with 27% given dicloxacillin and gentamicin, with a relative risk of 3.

Bell et al,²¹ in a large registry-based analysis from Scotland involving 7,666 elective orthopedic procedures, found that use of flucloxacillin 2 g plus a single dose of gentamicin 4 mg/kg was significantly associated with a 94% higher risk of acute kidney injury (KDIGO creatinine criteria) compared with a cefuroxime-based regimen, with absolute rates increasing from 6.2% to 10.8%.

Dubrovskaya et al²⁰ and Ferguson et al,²⁶ in contrast, found no increased risk with addition of gentamicin.

We recommend avoiding aminoglycosides for prophylaxis in primary lower-extremity total joint arthroplasty in patients at higher risk unless required for specific microbiologic reasons.

Vancomycin may also increase risk

Courtney et al¹⁹ assessed the risk of adding vancomycin to cefazolin for routine prophylaxis in a retrospective series of 1,828 total hip or knee arthroplasties and found a significantly higher rate of acute kidney injury, using AKIN criteria (13% vs 8%, odds ratio by multivariate analysis 1.82, P = .002).¹⁹

Other agents shown to be effective in treating periprosthetic joint infections or complicated skin and soft-tissue infections with resistant organisms include daptomycin⁴³ and linezolid.⁴⁴ These nonnephrotoxic alternatives to vancomycin may be a consideration if prophylaxis for methicillin-resistant Staphylococcus aureus is deemed necessary in patients at risk for acute kidney injury.

Deep infection may complicate nearly 1% of total hip⁴⁵ and 2% of total knee arthroplasties.⁴⁶ Kurtz et al^4,6 have projected that by 2030, infection will be the cause of two-thirds of the estimated 268,000 revision total knee arthroplasties and about half of the estimated 96,700 revision total hip arthroplasties.

The most common method of treating a chronically infected replacement joint is a 2-stage procedure.⁵ First, the prosthesis is removed, all infected bone and soft tissue is debrided, and an antibiotic-loaded cement spacer is implanted. Systemic antibiotics are given concurrently, typically for about 6 weeks. After the infection is brought under control, perhaps 2 to 3 months later, the spacer is removed and a new joint is implanted with antibiotic-loaded cement. A 1-stage procedure may be an option in selected cases and would obviate the need for an antibiotic-loaded cement spacer.^47,48

Of obvious relevance to development of acute kidney injury is the choice and amount of antibiotics embedded in the cement used for spacers and in implantation. Very high antibiotic levels are achieved within the joint space, usually with little systemic absorption, although significant systemic exposure has been documented in some cases.

The polymethylmethacrylate cement used for these purposes comes in 40-g bags. Multiple bags are typically required per joint, perhaps 2 to 4.⁴⁹

The rate of elution of antibiotics is determined by several factors, including surface area, porosity, and the number of antibiotics. In general, elution is greatest early on, with exponential decline lasting perhaps 1 week,  followed by slow, sustained release over weeks to months.⁵⁰ However, several in vitro studies have indicated that only about 5%^50,51 of the total antibiotic actually elutes over time.

Initially, multiple antibiotic-laden cement beads were used to fill the joint space, but this significantly limited function and mobility.⁵² Now, cement spacers are used, and they can be nonarticulating or articulating for maximal joint mobility.⁵³ Although much greater antibiotic elution occurs from beads due to their high surface area-to-volume ratio, spacers still provide an adequate dose.

ANTIBIOTIC-LOADED CEMENT: DOSAGE AND ELUTION CHARACTERISTICS

Antibiotic-loaded cement can be either low-dose or high-dose.

Low-dose cement

Low-dose cement typically consists of 0.5 to 1.0 g of antibiotic per 40-g bag of cement, usually an aminoglycoside (gentamicin or tobramycin) or vancomycin, and can be purchased premixed by the manufacturer. Such cement is only used prophylactically with primary total joint arthroplasty or revision for aseptic reasons, a practice common in Europe but less so in the United States. Some American authors propose antibiotic-loaded cement prophylaxis for patients at high risk, eg, those with immunosuppression, inflammatory cause of arthritis, or diabetes.⁵⁴

Vrabec et al,⁵⁵ in a study of low-dose tobramycin-loaded cement used for primary total knee arthroplasty, found a peak median intra-articular tobramycin concentration of 32 mg/L at 6 hours, declining to 6 mg/L at 48 hours with all serum levels 0.3 mg/L or less (unmeasureable) at similar time points.

Sterling et al,⁵⁶ studying primary total hip arthroplasties with low-dose tobramycin-loaded cement, found mean levels in drainage fluid of 103 mg/L at 6 hours, declining to 15 mg/L at 48 hours. Serum levels peaked at 0.94 mg/L at 3 hours, declining to 0.2 mg/L by 48 hours.

Although most of the antibiotic elution occurs early (within the first week), antibiotic can be found in joint aspirates up to 20 years later.⁵⁷ We are unaware of any well-documented cases of acute kidney injury ascribable to low-dose antibiotic-loaded cement used prophylactically. One case report making this assertion did not determine serum levels of aminoglycoside.⁵⁸

High-dose cement

High-dose antibiotic-loaded cement typically contains about 4 to 8 g of antibiotic per 40-g bag of cement and is used in the treatment of prosthetic joint infection to form the spacers. The antibiotic must be mixed into the cement powder by the surgeon in the operating room.

There is no standard combination or dosage. The choice of antibiotic can be tailored to the infecting organism if known. Otherwise, gram-positive organisms are most common, and vancomycin and aminoglycosides are often used together. This particular combination will enhance the elution of both antibiotics when studied in vitro, a process termed “passive opportunism.”⁵⁹ Other antibiotics in use include aztreonam, piperacillin, teicoplanin, fluoroquinolones, cephalosporins, and daptomycin, among others.

About 8 g of antibiotic total per 40-g bag is the maximum to allow easy molding.⁵² As an example, this may include 4 g of vancomycin and 3.6 g of tobramycin per 40 g. Given that 3 to 4 such bags are often used per joint, there is significant risk of systemic exposure.

Kalil et al⁶⁰ studied 8 patients who received high-dose tobramycin-loaded cement to treat periprosthetic joint infections of the hip or knee and found that 7 had detectable serum levels (mean 0.84 mg/L, highest 2.0 mg/L), including 1 with a level of 0.9 mg/L on day 38; 4 of these 8 developed acute kidney injury by AKIN criteria, although other risk factors for acute kidney injury existed. Nearly all had concomitant vancomycin (3 to 8 g) added to the cement as well.

Hsieh et al⁶¹ studied 46 patients with infected total hip arthroplasties treated with high-dose antibiotic-loaded cement spacers (vancomycin 4 g and aztreonam 4 g per 40-g bag) and found vancomycin levels in joint drainage higher than 1,500 mg/L on day 1, decreasing to 571 mg/L on day 7; serum levels were low (range 0.1–1.6 mg/L at 24 hours), falling to undetectable by 72 hours.

Case reports have associated high-dose antibiotic-loaded cement spacers with acute kidney injury.

Curtis et al⁶² described an 85-year-old patient with stage 3 chronic kidney disease who was treated for an infected total knee arthroplasty with an antibiotic-loaded cement spacer (containing 3.6 g of tobramycin and 3 g of cefazolin per 40-g bag, 3 bags total) and developed stage 3 acute kidney injury. After 16 days and 3 hemodialysis sessions, the patient’s serum tobramycin level was still 2 mg/L despite receiving no systemic tobramycin.

Wu et al⁶³ reported a case of acute kidney injury that required dialysis after implantation of a tobramycin- and vancomycin-loaded spacer, with persistent serum tobramycin levels despite repeated hemodialysis sessions until the spacer was removed.

Chalmers et al⁶⁴ described 2 patients with acute kidney injury and persistently elevated serum tobramycin levels (3.9 mg/L on day 39 in 1 patient and 2.0 mg/L on day 24 in the other patient) despite no systemic administration.

In these and other case reports,^65–67 dialysis and spacer explantation were usually required. 


Comment. It is intuitive that acute kidney injury would more likely complicate revision total joint arthroplasties for infection than for primary total joint arthroplasties or revisions for aseptic reasons, given the systemic effects of infection and exposure to nephrotoxic or allergenic antibiotics. And the available data suggest that the risk of acute kidney injury is higher with revision for prosthetic joint infection than with revision for aseptic reasons. However, many of the studies were retrospective, relatively small, single-center series and used different definitions of acute kidney injury.

Luu et al⁸³ performed a systematic review of studies published between January 1989 and June 2012 reporting systemic complications (including acute kidney injury) of 2-stage revision arthroplasties including placement of an antibiotic-loaded cement spacer for treatment of periprosthetic joint infection. Overall, 10 studies were identified with 544 total patients. Five of these studies, with 409 patients, reported at least 1 case of acute kidney injury for a total of 27 patients, giving an incidence of 6.6% in these studies.^68–71 The remaining 5 studies, totaling 135 patients, did not report any cases of acute kidney injury,^{50,61,76–78} although that was not the primary focus of any of those trials.

Most notable from this systematic review, the study of Menge et al⁶⁹ retrospectively determined the incidence of acute kidney injury (defined as a 50% rise in serum creatinine to > 1.4 mg/dL within 90 days of surgery) to be 17% in 84 patients with infected total knee arthroplasties treated with antibiotic-loaded cement spacers. A mean of 3.5 bags of cement per spacer were used in the 35 articulating spacers, compared with 2.9 per nonarticulating spacer. These spacers contained vancomycin in 82% (median 4.0 g, range 1–16 g) and tobramycin in 94% (median 4.8 g, range 1–12 g), among others in small percentages. The dose of tobramycin in the spacer considered either as a dichotomous variable (> 4.8 g, OR 5.87) or linearly (OR 1.24 per 1-g increase) was significantly associated with acute kidney injury, although systemic administration of aminoglycosides or vancomycin was not.

Additional single-center series that were published subsequent to this review have generally used more current diagnostic criteria.

Noto et al⁷² found that 10 of 46 patients treated with antibiotic-loaded cement spacers had a greater than 50% rise in serum creatinine (average increase 260%). All spacers contained tobramycin (mean dose 8.2 g), and 9 of 10 also contained vancomycin (mean 7.6 g). All of the 9 patients with acute kidney injury with follow-up data recovered renal function.

Reed et al⁷⁵ found 26 cases of acute kidney injury (based on RIFLE creatinine criteria) in 306 patients with antibiotic-loaded cement spacers treating various periprosthetic joint infections (including hips, knees, shoulders, and digits) and compared them with 74 controls who did not develop acute kidney injury. By multivariable analysis, receipt of an ACE inhibitor within 7 days of surgery and receipt of piperacillin-tazobactam within 7 days after surgery were both significantly more common in cases with acute kidney injury than in controls without acute kidney injury.

Aeng et al⁷³ prospectively studied 50 consecutive patients receiving antibiotic-loaded spacers containing tobramycin (with or without vancomycin) for treatment of infected hip or knee replacements. Using RIFLE creatinine criteria, they found an incidence of acute kidney injury of 20% (10 of 50). Factors significantly associated with acute kidney injury included cement premixed by the manufacturer with gentamicin (0.5 g per 40-g bag) in addition to the tobramycin they added, intraoperative blood transfusions, and postoperative use of nonsteroidal anti-inflammatory drugs.

Geller et al,⁷⁴ in a multicenter retrospective study of 247 patients with prosthetic joint infections (156 knees and 91 hips) undergoing antibiotic-loaded cement spacer placement, found an incidence of acute kidney injury of 26% based on KDIGO creatinine criteria. Significant risk factors included higher body mass index, lower preoperative hemoglobin level, drop in hemoglobin after surgery, and comorbidity (hypertension, diabetes, chronic kidney disease, or cardiovascular disease). Most of the spacers contained a combination of vancomycin and either tobramycin (81%) or gentamicin (13%). The spacers contained an average of 5.3 g (range 0.6–18 g) of vancomycin (average 2.65 g per 40-g bag) and an average of 5.2 g (range 0.5–16.4 g) of tobramycin (average 2.6 g per bag).

As in Menge et al,⁶⁹ this study illustrates the wide range of antibiotic dosages in use and the lack of standardization. In contrast to the study by Menge et al, however, development of acute kidney injury was not related to the amount of vancomycin or tobramycin contained in the spacers. Eventual clearance of infection (at 1 and 2 years) was significantly related to increasing amounts of vancomycin. Multiple different systemic antibiotics were used, most commonly vancomycin (44%), and systemic vancomycin was not associated with acute kidney injury.

Yadav et al,⁸¹ in a study of 3,129 consecutive revision procedures of the knee or hip, found an incidence of acute kidney injury by RIFLE creatinine criteria of 29% in the 197 patients who received antibiotic-loaded cement spacers for periprosthetic joint infection compared with 3.4% in the 2,848 who underwent revision for aseptic reasons. In 84 patients with prosthetic joint infection having various surgeries not including placement of a spacer, the acute kidney injury rate at some point in their course was an alarmingly high 82%. In the group that received spacers, only age and comorbidity as assessed by Charlson comorbidity index were independently associated with acute kidney injury by multivariate analysis. Surprisingly, modest renal impairment was protective, possibly because physicians of patients with chronic kidney disease were more vigilant and took appropriate measures to prevent acute kidney injury.

Overall, the risk of acute kidney injury appears to be much higher during treatment of prosthetic joint infection with a 2-stage procedure using an antibiotic-loaded cement spacer than after primary total joint arthroplasty or revision for aseptic reasons, and may complicate up to one-third of cases.

As in primary total joint arthroplasty in general, higher-risk cases should be identified based on age, body mass index, chronic kidney disease, comorbidities (hypertension, diabetes, established cardiovascular disease), and anemia.

Preoperative transfusion can be considered case by case depending on degree of anemia and associated risk factors.

All renin-angiotensin-aldosterone system inhibitors should be withheld starting 1 week before surgery.

Both nonselective and cyclooxygenase-2 selective nonsteroidal anti-inflammatory drugs should be avoided, if possible.

Strict attention should be paid to adequate intraoperative and postoperative fluid resuscitation.

Kidney function should be monitored closely in the early postoperative period, including urine output and daily creatinine for at least 72 hours.

Systemic administration of potentially nephrotoxic antibiotics should be minimized, especially the combination of vancomycin with piperacillin-tazobactam.⁸⁴ Daptomycin is a consideration.⁴³

If acute kidney injury should develop, serum levels of vancomycin or aminoglycosides should be measured if the spacer contains these antibiotics. The spacer may need to be removed if toxic serum levels persist.

TAKE-HOME POINTS

Acute kidney injury may complicate up to 10% of primary lower-extremity total joint arthroplasties and up to 25% of periprosthetic joint infections treated with a 2-stage procedure including placement of an antibiotic-loaded cement spacer in the first stage.

Risk factors for acute kidney injury include older age, obesity, chronic kidney disease, and overall comorbidity. Potentially modifiable risk factors include anemia, perioperative transfusions, aminoglycoside prophylaxis, perioperative renin-angiotensin system blockade, and postoperative nonsteroidal anti-inflammatory drugs. These should be mitigated when possible.

In patients with periprosthetic joint infection who receive antibiotic-loaded cement spacers, especially patients  with additional risk factors for acute kidney injury, strict attention should be paid to the dose of antibiotic in the spacer, with levels checked postoperatively if necessary. Nonnephrotoxic antibiotics should be chosen for systemic administration when possible.

Prospective randomized controlled trials are needed to guide therapy after total joint arthroplasty, and to verify the adverse long-term outcomes of acute kidney injury in this setting.

A 60-year-old man is admitted for respiratory failure following a massive myocardial infarction. He develops ventilator-associated pneumonia and is treated with cefepime and vancomycin. Three days later, he develops prolonged atypical absence seizures.

What caused these seizures? The neurologist thinks it might be the cefepime. Do you agree?

Antibiotics are widely used in the United States, with 269 million courses of oral therapy prescribed in 2011.¹ Adverse effects such as rash are well known, but rare effects such as seizure, hypoglycemia, and hypoxemia may not be immediately attributed to these drugs.

In this article, we review less-recognized but potentially serious adverse effects of antibiotics commonly prescribed in the United States. We have structured our discussion by organ system for ease of reference.

NERVOUS SYSTEM

The potential adverse effects of antibiotics on the nervous system range from encephalopathy and seizure to nonconvulsive status epilepticus.

Encephalopathy and seizure

Encephalopathy has been reported with penicillins, cephalosporins, sulfamethoxazole-trimethoprim, quinolones, and oxazolidinones such as linezolid.^2,3

Seizures are known to occur with penicillins, cephalosporins, carbapenems, and quinolones.^2–4 For cephalosporins, these effects are more common at higher doses, in elderly patients, and in patients with renal impairment. Carbapenems are associated with seizure activity in elderly patients.^2–4

Encephalopathy and seizure can also occur on a continuum, as is the case with piperacillin-induced encephalopathy, with progressive dysarthria, tremor, and progressive confusion culminating in tonic-clonic seizures.²

Nonconvulsive status epilepticus

Nonconvulsive status epilepticus, marked by prolonged atypical absence seizures, has complicated the use of penicillins, quinolones, clarithromycin, and cephalosporins, specifically cefepime.^2,3,5 Diagnosis can be difficult and requires clinical awareness and confirmation with electroencephalography.

Class-specific neurologic effects

Certain antibiotics have class-specific effects:

Tetracyclines: cranial nerve toxicity, neuromuscular blockade, and intracranial hypertension.²

Sulfamethoxazole-trimethoprim: tremors and psychosis, with visual and auditory hallucinations.⁶

Macrolides: dysequilibrium and potentially irreversible hearing loss.²

Quinolones: orofacial dyskinesia and a Tourette-like syndrome, with a higher incidence reported with newer quinolones.⁷

Linezolid: optic and peripheral neuropathy²; neuropathy can be persistent and can lead to loss of vision. The package insert recommends monitoring visual function in patients taking linezolid for more than 3 months and in any patient reporting visual symptoms.⁸

Linezolid is also associated with serotonin syndrome when combined with a drug that potentiates serotonergic activity, most commonly selective serotonin reuptake inhibitors. The syndrome is characterized by a triad of cognitive or behavioral changes, autonomic instability, and neuromuscular excitability such as spontaneous clonus.⁹

Metronidazole: optic and peripheral neuropathy, in addition to cerebellar toxicity and central nervous system lesions on magnetic resonance imaging of the brain. In a series of 11 cases of cerebellar toxicity, most patients presented with ataxia and dysarthria associated with high total doses of metronidazole, and in most cases, magnetic resonance imaging showed resolution of the lesions upon discontinuation of metronidazole.¹⁰

HEMATOLOGIC AND RHEUMATOLOGIC EFFECTS

Agranulocytosis has been associated with beta-lactams, in most cases with prolonged exposure. In one report, the average exposure before onset of agranulocytosis was 22 days for nafcillin and 25 days for penicillin. For penicillins, more than 50% of cases involved high daily doses.¹¹

Likewise, most episodes of vancomycin-induced neutropenia were reported to occur after 20 days of therapy.¹²

In another study, most cases of drug-induced anemia were due to ceftriaxone and piperacillin.¹³

Drug-induced thrombocytopenia has been described with penicillins, cephalo­sporins, sulfonamides, and vancomycin¹⁴ and is a well-recognized effect of linezolid. The syndrome of drug reaction with eosinophilia and systemic symptoms, a severe and rare adverse reaction, has been reported with minocycline, sulfamethoxazole, and vancomycin.¹⁵

The tetracycline minocycline has been reported to cause drug-induced lupus and polyarteritis nodosa-like vasculitis.¹⁶ Drug-induced lupus presents as myalgias and arthralgias, serositis, constitutional symptoms, and positive antinuclear antibody titers. The effect is not dose-dependent. Penicillin, cefuroxime, and nitrofurantoin have also been implicated.¹⁶

Kermani et al¹⁷ described 9 cases of polyarteritis nodosa, in which 5 patients (56%) had systemic involvement including renal artery microaneurysm, mononeuritis multiplex, and mesenteric vasculitis, and some of these patients also had cutaneous involvement. All patients had positive antineutrophil cytoplasmic antibody in a perinuclear pattern. The median time from start of the minocycline to symptom onset was 9 months, and the median duration of use was 2 years.

Quinolones have also been reported to cause fatal hypersensitivity vasculitis.^18,19

CARDIOVASCULAR SYSTEM

Macrolides and quinolones have been reported to cause QT-interval prolongation and torsades de pointes. The risk is greatest when a  macrolide is co-administered with a CYP3A4 inhibitor.

Of the macrolides, azithromycin is the safest, as clarithromycin and erythromycin are more likely to cause QT prolongation.

While QT prolongation is a class effect of quinolones, there is variability within the class. Ciprofloxacin is thought to be the safest in terms of cardiovascular adverse effects.²⁰ In addition, Owens and Nolin²⁰ reported that quinolone-associated QT prolongation was more likely to occur in patients with pre-existing QT prolongation, electrolyte abnormalities, organic heart disease, and bradycardia, and especially in women. Other risk factors for QT prolongation with quinolone use include underlying cardiac disease and advanced age.²¹

Quinolones have also been associated with an increased risk of aortic dissection. The US Food and Drug Administration has issued a warning advising clinicians to avoid quinolones in patients who have aneurysms or are at risk for aneurysms, such as patients with advanced age, peripheral atherosclerotic vascular disease, hypertension and conditions such as Marfan and Ehlers-Danlos syndrome.²²

DIGESTIVE SYSTEM

Tetracyclines are known to cause esophagitis from direct contact with and disruption of the mucosal lining. Doxycycline is the most frequent offender.²³

Amoxicillin-clavulanate is the antibiotic most commonly associated with drug-induced liver injury, mainly attributable to the clavulanate component.²⁴ It is more common in men over age 50 and with prolonged and repeated dosing and is sometimes fatal. Other adverse effects include Stevens-Johnson syndrome, interstitial nephritis, and thrombotic thrombocytopenic purpura.²⁵

Cholestatic hepatitis has been reported with penicillins, particularly dicloxacillin, oxacillin, and amoxicillin-clavulanate; cephalosporins; doxycycline; sulfamethoxazole-trimethoprim; macrolides; and ciprofloxacin.^24–26 Hepatocellular injury is linked to amoxicillin-clavulanate and doxycycline. Drug-induced mixed liver injury has been observed with amoxicillin-clavulanate, sulfamethoxazole-trimethoprim and, rarely, cephalosporins.

Liver injury is classified as cholestatic if the alkaline phosphatase level is more than 2 times higher than normal, or if the ratio of alanine aminotransferase to alkaline phosphatase is less than 2; if the ratio is greater than 5, the injury is considered hepatocellular.²⁴ Mixed liver injury, the most common, is defined as a ratio from 2 to 5.

Nitrofurantoin has also been linked to hepatotoxicity, cirrhosis, and end-stage liver disease, and to death if the drug is continued after the onset of jaundice.²⁶ Death from liver injury has been reported with amoxicillin-clavulanate, sulfamethoxazole-trimethoprim, and erythromycin, and jaundice indicates a poor prognosis, associated with a 10% mortality rate or need for liver transplant in all patients.²⁴

ENDOCRINE SYSTEM

Clarithromycin, sulfonamides, and quinolones are known to precipitate hypoglycemia by interacting with sulfonylureas. A study of Medicare patients age 66 or older who were taking glipizide or glyburide reported that female sex, older age, and a history of hypoglycemic episodes were associated with antibiotic-related hypoglycemia.²⁷ The odds ratio for hypoglycemia was highest for clarithromycin (3.96), sulfamethoxazole-trimethoprim (2.56), metronidazole (2.11), and ciprofloxacin (1.62) when compared with antibiotics that do not cause hypoglycemia. There was no signal for levofloxacin-mediated hypoglycemia in this series.²⁷

RESPIRATORY SYSTEM

Hypersensitivity lung disease has been reported with penicillin, ampicillin, cephalosporins, ciprofloxacin, and sulfonamides including sulfamethoxazole-trimethoprim.²⁸ The lipopeptide daptomycin has been reported to cause acute eosinophilic pneumonia defined as fever for less than 5 days, pulmonary infiltrates, hypoxemia, and a bronchoalveolar lavage or biopsy study with eosinophils. Daptomycin should be stopped early in these cases, and the patient should not be rechallenged, as the reaction can be deadly.²⁹

Nitrofurantoin has a long history of hypersensitivity pneumonitis in its acute form and a chronic allergic response. While more widely recognized, nitrofurantoin pulmonary toxicity is rare, occurring in 1 in 5,000 patients.³⁰

RENAL SYSTEM

Acute interstitial nephritis has been reported with penicillins, cephalosporins, macrolides, quinolones, sulfonamides, and vancomycin.^31–33 Acute tubular necrosis has been linked to cephalosporins and tetracyclines. Crystal nephropathy has been seen with quinolones and sulfonamides.

Advanced age is an important risk factor for renal dysfunction from quinolones,¹⁸ and penicillin G has been reported to cause glomerulonephritis.³¹

MUSCULOSKELETAL SYSTEM

Quinolones have been associated with arthropathy or tendinitis at a rate of 1%, including cases of Achilles tendon rupture.¹⁸ The US Food and Drug Administration announced in 2016 that the serious adverse events with fluoroquinolones outweigh the benefits in patients with acute sinusitis, acute bronchitis, and uncomplicated urinary tract infection, and that they should be used only if there are no other options.³⁴

Daptomycin is known to cause elevations of creatine kinase.³⁴ Weekly monitoring is recommended based on postmarketing data reports of elevations in 2.5% of patients; myopathy is a rarer effect, occurring in 0.2% of patients.³⁵

REPRODUCTIVE SYSTEM

Antibiotics have long been reported to interact with oral contraceptives, but the data are not compelling for commonly used antibiotics. The strongest association is with rifampicin, which reduces oral contraceptive efficacy and warrants an alternative mode of contraception.³⁶

BACK TO OUR PATIENT

Antibiotics can have serious adverse effects, and it is important for clinicians to be cognizant of this. Our 60-year-old patient who was taking cefepime and vancomycin for pneumonia developed prolonged atypical absence seizures. When the cefepime was discontinued, his mental status improved, and no other seizures were observed.

A 60-year-old man is admitted for respiratory failure following a massive myocardial infarction. He develops ventilator-associated pneumonia and is treated with cefepime and vancomycin. Three days later, he develops prolonged atypical absence seizures.

What caused these seizures? The neurologist thinks it might be the cefepime. Do you agree?

Antibiotics are widely used in the United States, with 269 million courses of oral therapy prescribed in 2011.¹ Adverse effects such as rash are well known, but rare effects such as seizure, hypoglycemia, and hypoxemia may not be immediately attributed to these drugs.

In this article, we review less-recognized but potentially serious adverse effects of antibiotics commonly prescribed in the United States. We have structured our discussion by organ system for ease of reference.

NERVOUS SYSTEM

The potential adverse effects of antibiotics on the nervous system range from encephalopathy and seizure to nonconvulsive status epilepticus.

Encephalopathy and seizure

Encephalopathy has been reported with penicillins, cephalosporins, sulfamethoxazole-trimethoprim, quinolones, and oxazolidinones such as linezolid.^2,3

Seizures are known to occur with penicillins, cephalosporins, carbapenems, and quinolones.^2–4 For cephalosporins, these effects are more common at higher doses, in elderly patients, and in patients with renal impairment. Carbapenems are associated with seizure activity in elderly patients.^2–4

Encephalopathy and seizure can also occur on a continuum, as is the case with piperacillin-induced encephalopathy, with progressive dysarthria, tremor, and progressive confusion culminating in tonic-clonic seizures.²

Nonconvulsive status epilepticus

Nonconvulsive status epilepticus, marked by prolonged atypical absence seizures, has complicated the use of penicillins, quinolones, clarithromycin, and cephalosporins, specifically cefepime.^2,3,5 Diagnosis can be difficult and requires clinical awareness and confirmation with electroencephalography.

Class-specific neurologic effects

Certain antibiotics have class-specific effects:

Tetracyclines: cranial nerve toxicity, neuromuscular blockade, and intracranial hypertension.²

Sulfamethoxazole-trimethoprim: tremors and psychosis, with visual and auditory hallucinations.⁶

Macrolides: dysequilibrium and potentially irreversible hearing loss.²

Quinolones: orofacial dyskinesia and a Tourette-like syndrome, with a higher incidence reported with newer quinolones.⁷

Linezolid: optic and peripheral neuropathy²; neuropathy can be persistent and can lead to loss of vision. The package insert recommends monitoring visual function in patients taking linezolid for more than 3 months and in any patient reporting visual symptoms.⁸

Linezolid is also associated with serotonin syndrome when combined with a drug that potentiates serotonergic activity, most commonly selective serotonin reuptake inhibitors. The syndrome is characterized by a triad of cognitive or behavioral changes, autonomic instability, and neuromuscular excitability such as spontaneous clonus.⁹

Metronidazole: optic and peripheral neuropathy, in addition to cerebellar toxicity and central nervous system lesions on magnetic resonance imaging of the brain. In a series of 11 cases of cerebellar toxicity, most patients presented with ataxia and dysarthria associated with high total doses of metronidazole, and in most cases, magnetic resonance imaging showed resolution of the lesions upon discontinuation of metronidazole.¹⁰

HEMATOLOGIC AND RHEUMATOLOGIC EFFECTS

Agranulocytosis has been associated with beta-lactams, in most cases with prolonged exposure. In one report, the average exposure before onset of agranulocytosis was 22 days for nafcillin and 25 days for penicillin. For penicillins, more than 50% of cases involved high daily doses.¹¹

Likewise, most episodes of vancomycin-induced neutropenia were reported to occur after 20 days of therapy.¹²

In another study, most cases of drug-induced anemia were due to ceftriaxone and piperacillin.¹³

Drug-induced thrombocytopenia has been described with penicillins, cephalo­sporins, sulfonamides, and vancomycin¹⁴ and is a well-recognized effect of linezolid. The syndrome of drug reaction with eosinophilia and systemic symptoms, a severe and rare adverse reaction, has been reported with minocycline, sulfamethoxazole, and vancomycin.¹⁵

The tetracycline minocycline has been reported to cause drug-induced lupus and polyarteritis nodosa-like vasculitis.¹⁶ Drug-induced lupus presents as myalgias and arthralgias, serositis, constitutional symptoms, and positive antinuclear antibody titers. The effect is not dose-dependent. Penicillin, cefuroxime, and nitrofurantoin have also been implicated.¹⁶

Kermani et al¹⁷ described 9 cases of polyarteritis nodosa, in which 5 patients (56%) had systemic involvement including renal artery microaneurysm, mononeuritis multiplex, and mesenteric vasculitis, and some of these patients also had cutaneous involvement. All patients had positive antineutrophil cytoplasmic antibody in a perinuclear pattern. The median time from start of the minocycline to symptom onset was 9 months, and the median duration of use was 2 years.

Quinolones have also been reported to cause fatal hypersensitivity vasculitis.^18,19

CARDIOVASCULAR SYSTEM

Macrolides and quinolones have been reported to cause QT-interval prolongation and torsades de pointes. The risk is greatest when a  macrolide is co-administered with a CYP3A4 inhibitor.

Of the macrolides, azithromycin is the safest, as clarithromycin and erythromycin are more likely to cause QT prolongation.

While QT prolongation is a class effect of quinolones, there is variability within the class. Ciprofloxacin is thought to be the safest in terms of cardiovascular adverse effects.²⁰ In addition, Owens and Nolin²⁰ reported that quinolone-associated QT prolongation was more likely to occur in patients with pre-existing QT prolongation, electrolyte abnormalities, organic heart disease, and bradycardia, and especially in women. Other risk factors for QT prolongation with quinolone use include underlying cardiac disease and advanced age.²¹

Quinolones have also been associated with an increased risk of aortic dissection. The US Food and Drug Administration has issued a warning advising clinicians to avoid quinolones in patients who have aneurysms or are at risk for aneurysms, such as patients with advanced age, peripheral atherosclerotic vascular disease, hypertension and conditions such as Marfan and Ehlers-Danlos syndrome.²²

DIGESTIVE SYSTEM

Tetracyclines are known to cause esophagitis from direct contact with and disruption of the mucosal lining. Doxycycline is the most frequent offender.²³

Amoxicillin-clavulanate is the antibiotic most commonly associated with drug-induced liver injury, mainly attributable to the clavulanate component.²⁴ It is more common in men over age 50 and with prolonged and repeated dosing and is sometimes fatal. Other adverse effects include Stevens-Johnson syndrome, interstitial nephritis, and thrombotic thrombocytopenic purpura.²⁵

Cholestatic hepatitis has been reported with penicillins, particularly dicloxacillin, oxacillin, and amoxicillin-clavulanate; cephalosporins; doxycycline; sulfamethoxazole-trimethoprim; macrolides; and ciprofloxacin.^24–26 Hepatocellular injury is linked to amoxicillin-clavulanate and doxycycline. Drug-induced mixed liver injury has been observed with amoxicillin-clavulanate, sulfamethoxazole-trimethoprim and, rarely, cephalosporins.

Liver injury is classified as cholestatic if the alkaline phosphatase level is more than 2 times higher than normal, or if the ratio of alanine aminotransferase to alkaline phosphatase is less than 2; if the ratio is greater than 5, the injury is considered hepatocellular.²⁴ Mixed liver injury, the most common, is defined as a ratio from 2 to 5.

Nitrofurantoin has also been linked to hepatotoxicity, cirrhosis, and end-stage liver disease, and to death if the drug is continued after the onset of jaundice.²⁶ Death from liver injury has been reported with amoxicillin-clavulanate, sulfamethoxazole-trimethoprim, and erythromycin, and jaundice indicates a poor prognosis, associated with a 10% mortality rate or need for liver transplant in all patients.²⁴

ENDOCRINE SYSTEM

Clarithromycin, sulfonamides, and quinolones are known to precipitate hypoglycemia by interacting with sulfonylureas. A study of Medicare patients age 66 or older who were taking glipizide or glyburide reported that female sex, older age, and a history of hypoglycemic episodes were associated with antibiotic-related hypoglycemia.²⁷ The odds ratio for hypoglycemia was highest for clarithromycin (3.96), sulfamethoxazole-trimethoprim (2.56), metronidazole (2.11), and ciprofloxacin (1.62) when compared with antibiotics that do not cause hypoglycemia. There was no signal for levofloxacin-mediated hypoglycemia in this series.²⁷

RESPIRATORY SYSTEM

Hypersensitivity lung disease has been reported with penicillin, ampicillin, cephalosporins, ciprofloxacin, and sulfonamides including sulfamethoxazole-trimethoprim.²⁸ The lipopeptide daptomycin has been reported to cause acute eosinophilic pneumonia defined as fever for less than 5 days, pulmonary infiltrates, hypoxemia, and a bronchoalveolar lavage or biopsy study with eosinophils. Daptomycin should be stopped early in these cases, and the patient should not be rechallenged, as the reaction can be deadly.²⁹

Nitrofurantoin has a long history of hypersensitivity pneumonitis in its acute form and a chronic allergic response. While more widely recognized, nitrofurantoin pulmonary toxicity is rare, occurring in 1 in 5,000 patients.³⁰

RENAL SYSTEM

Acute interstitial nephritis has been reported with penicillins, cephalosporins, macrolides, quinolones, sulfonamides, and vancomycin.^31–33 Acute tubular necrosis has been linked to cephalosporins and tetracyclines. Crystal nephropathy has been seen with quinolones and sulfonamides.

Advanced age is an important risk factor for renal dysfunction from quinolones,¹⁸ and penicillin G has been reported to cause glomerulonephritis.³¹

MUSCULOSKELETAL SYSTEM

Quinolones have been associated with arthropathy or tendinitis at a rate of 1%, including cases of Achilles tendon rupture.¹⁸ The US Food and Drug Administration announced in 2016 that the serious adverse events with fluoroquinolones outweigh the benefits in patients with acute sinusitis, acute bronchitis, and uncomplicated urinary tract infection, and that they should be used only if there are no other options.³⁴

Daptomycin is known to cause elevations of creatine kinase.³⁴ Weekly monitoring is recommended based on postmarketing data reports of elevations in 2.5% of patients; myopathy is a rarer effect, occurring in 0.2% of patients.³⁵

REPRODUCTIVE SYSTEM

Antibiotics have long been reported to interact with oral contraceptives, but the data are not compelling for commonly used antibiotics. The strongest association is with rifampicin, which reduces oral contraceptive efficacy and warrants an alternative mode of contraception.³⁶

BACK TO OUR PATIENT

Antibiotics can have serious adverse effects, and it is important for clinicians to be cognizant of this. Our 60-year-old patient who was taking cefepime and vancomycin for pneumonia developed prolonged atypical absence seizures. When the cefepime was discontinued, his mental status improved, and no other seizures were observed.

A 60-year-old man is admitted for respiratory failure following a massive myocardial infarction. He develops ventilator-associated pneumonia and is treated with cefepime and vancomycin. Three days later, he develops prolonged atypical absence seizures.

What caused these seizures? The neurologist thinks it might be the cefepime. Do you agree?

Antibiotics are widely used in the United States, with 269 million courses of oral therapy prescribed in 2011.¹ Adverse effects such as rash are well known, but rare effects such as seizure, hypoglycemia, and hypoxemia may not be immediately attributed to these drugs.

In this article, we review less-recognized but potentially serious adverse effects of antibiotics commonly prescribed in the United States. We have structured our discussion by organ system for ease of reference.

NERVOUS SYSTEM

The potential adverse effects of antibiotics on the nervous system range from encephalopathy and seizure to nonconvulsive status epilepticus.

Encephalopathy and seizure

Encephalopathy has been reported with penicillins, cephalosporins, sulfamethoxazole-trimethoprim, quinolones, and oxazolidinones such as linezolid.^2,3

Seizures are known to occur with penicillins, cephalosporins, carbapenems, and quinolones.^2–4 For cephalosporins, these effects are more common at higher doses, in elderly patients, and in patients with renal impairment. Carbapenems are associated with seizure activity in elderly patients.^2–4

Encephalopathy and seizure can also occur on a continuum, as is the case with piperacillin-induced encephalopathy, with progressive dysarthria, tremor, and progressive confusion culminating in tonic-clonic seizures.²

Nonconvulsive status epilepticus

Nonconvulsive status epilepticus, marked by prolonged atypical absence seizures, has complicated the use of penicillins, quinolones, clarithromycin, and cephalosporins, specifically cefepime.^2,3,5 Diagnosis can be difficult and requires clinical awareness and confirmation with electroencephalography.

Class-specific neurologic effects

Certain antibiotics have class-specific effects:

Tetracyclines: cranial nerve toxicity, neuromuscular blockade, and intracranial hypertension.²

Sulfamethoxazole-trimethoprim: tremors and psychosis, with visual and auditory hallucinations.⁶

Macrolides: dysequilibrium and potentially irreversible hearing loss.²

Quinolones: orofacial dyskinesia and a Tourette-like syndrome, with a higher incidence reported with newer quinolones.⁷

Linezolid: optic and peripheral neuropathy²; neuropathy can be persistent and can lead to loss of vision. The package insert recommends monitoring visual function in patients taking linezolid for more than 3 months and in any patient reporting visual symptoms.⁸

Linezolid is also associated with serotonin syndrome when combined with a drug that potentiates serotonergic activity, most commonly selective serotonin reuptake inhibitors. The syndrome is characterized by a triad of cognitive or behavioral changes, autonomic instability, and neuromuscular excitability such as spontaneous clonus.⁹

Metronidazole: optic and peripheral neuropathy, in addition to cerebellar toxicity and central nervous system lesions on magnetic resonance imaging of the brain. In a series of 11 cases of cerebellar toxicity, most patients presented with ataxia and dysarthria associated with high total doses of metronidazole, and in most cases, magnetic resonance imaging showed resolution of the lesions upon discontinuation of metronidazole.¹⁰

HEMATOLOGIC AND RHEUMATOLOGIC EFFECTS

Agranulocytosis has been associated with beta-lactams, in most cases with prolonged exposure. In one report, the average exposure before onset of agranulocytosis was 22 days for nafcillin and 25 days for penicillin. For penicillins, more than 50% of cases involved high daily doses.¹¹

Likewise, most episodes of vancomycin-induced neutropenia were reported to occur after 20 days of therapy.¹²

In another study, most cases of drug-induced anemia were due to ceftriaxone and piperacillin.¹³

Drug-induced thrombocytopenia has been described with penicillins, cephalo­sporins, sulfonamides, and vancomycin¹⁴ and is a well-recognized effect of linezolid. The syndrome of drug reaction with eosinophilia and systemic symptoms, a severe and rare adverse reaction, has been reported with minocycline, sulfamethoxazole, and vancomycin.¹⁵

The tetracycline minocycline has been reported to cause drug-induced lupus and polyarteritis nodosa-like vasculitis.¹⁶ Drug-induced lupus presents as myalgias and arthralgias, serositis, constitutional symptoms, and positive antinuclear antibody titers. The effect is not dose-dependent. Penicillin, cefuroxime, and nitrofurantoin have also been implicated.¹⁶

Kermani et al¹⁷ described 9 cases of polyarteritis nodosa, in which 5 patients (56%) had systemic involvement including renal artery microaneurysm, mononeuritis multiplex, and mesenteric vasculitis, and some of these patients also had cutaneous involvement. All patients had positive antineutrophil cytoplasmic antibody in a perinuclear pattern. The median time from start of the minocycline to symptom onset was 9 months, and the median duration of use was 2 years.

Quinolones have also been reported to cause fatal hypersensitivity vasculitis.^18,19

CARDIOVASCULAR SYSTEM

Macrolides and quinolones have been reported to cause QT-interval prolongation and torsades de pointes. The risk is greatest when a  macrolide is co-administered with a CYP3A4 inhibitor.

Of the macrolides, azithromycin is the safest, as clarithromycin and erythromycin are more likely to cause QT prolongation.

While QT prolongation is a class effect of quinolones, there is variability within the class. Ciprofloxacin is thought to be the safest in terms of cardiovascular adverse effects.²⁰ In addition, Owens and Nolin²⁰ reported that quinolone-associated QT prolongation was more likely to occur in patients with pre-existing QT prolongation, electrolyte abnormalities, organic heart disease, and bradycardia, and especially in women. Other risk factors for QT prolongation with quinolone use include underlying cardiac disease and advanced age.²¹

Quinolones have also been associated with an increased risk of aortic dissection. The US Food and Drug Administration has issued a warning advising clinicians to avoid quinolones in patients who have aneurysms or are at risk for aneurysms, such as patients with advanced age, peripheral atherosclerotic vascular disease, hypertension and conditions such as Marfan and Ehlers-Danlos syndrome.²²

DIGESTIVE SYSTEM

Tetracyclines are known to cause esophagitis from direct contact with and disruption of the mucosal lining. Doxycycline is the most frequent offender.²³

Amoxicillin-clavulanate is the antibiotic most commonly associated with drug-induced liver injury, mainly attributable to the clavulanate component.²⁴ It is more common in men over age 50 and with prolonged and repeated dosing and is sometimes fatal. Other adverse effects include Stevens-Johnson syndrome, interstitial nephritis, and thrombotic thrombocytopenic purpura.²⁵

Cholestatic hepatitis has been reported with penicillins, particularly dicloxacillin, oxacillin, and amoxicillin-clavulanate; cephalosporins; doxycycline; sulfamethoxazole-trimethoprim; macrolides; and ciprofloxacin.^24–26 Hepatocellular injury is linked to amoxicillin-clavulanate and doxycycline. Drug-induced mixed liver injury has been observed with amoxicillin-clavulanate, sulfamethoxazole-trimethoprim and, rarely, cephalosporins.

Liver injury is classified as cholestatic if the alkaline phosphatase level is more than 2 times higher than normal, or if the ratio of alanine aminotransferase to alkaline phosphatase is less than 2; if the ratio is greater than 5, the injury is considered hepatocellular.²⁴ Mixed liver injury, the most common, is defined as a ratio from 2 to 5.

Nitrofurantoin has also been linked to hepatotoxicity, cirrhosis, and end-stage liver disease, and to death if the drug is continued after the onset of jaundice.²⁶ Death from liver injury has been reported with amoxicillin-clavulanate, sulfamethoxazole-trimethoprim, and erythromycin, and jaundice indicates a poor prognosis, associated with a 10% mortality rate or need for liver transplant in all patients.²⁴

ENDOCRINE SYSTEM

Clarithromycin, sulfonamides, and quinolones are known to precipitate hypoglycemia by interacting with sulfonylureas. A study of Medicare patients age 66 or older who were taking glipizide or glyburide reported that female sex, older age, and a history of hypoglycemic episodes were associated with antibiotic-related hypoglycemia.²⁷ The odds ratio for hypoglycemia was highest for clarithromycin (3.96), sulfamethoxazole-trimethoprim (2.56), metronidazole (2.11), and ciprofloxacin (1.62) when compared with antibiotics that do not cause hypoglycemia. There was no signal for levofloxacin-mediated hypoglycemia in this series.²⁷

RESPIRATORY SYSTEM

Hypersensitivity lung disease has been reported with penicillin, ampicillin, cephalosporins, ciprofloxacin, and sulfonamides including sulfamethoxazole-trimethoprim.²⁸ The lipopeptide daptomycin has been reported to cause acute eosinophilic pneumonia defined as fever for less than 5 days, pulmonary infiltrates, hypoxemia, and a bronchoalveolar lavage or biopsy study with eosinophils. Daptomycin should be stopped early in these cases, and the patient should not be rechallenged, as the reaction can be deadly.²⁹

Nitrofurantoin has a long history of hypersensitivity pneumonitis in its acute form and a chronic allergic response. While more widely recognized, nitrofurantoin pulmonary toxicity is rare, occurring in 1 in 5,000 patients.³⁰

RENAL SYSTEM

Acute interstitial nephritis has been reported with penicillins, cephalosporins, macrolides, quinolones, sulfonamides, and vancomycin.^31–33 Acute tubular necrosis has been linked to cephalosporins and tetracyclines. Crystal nephropathy has been seen with quinolones and sulfonamides.

Advanced age is an important risk factor for renal dysfunction from quinolones,¹⁸ and penicillin G has been reported to cause glomerulonephritis.³¹

MUSCULOSKELETAL SYSTEM

Quinolones have been associated with arthropathy or tendinitis at a rate of 1%, including cases of Achilles tendon rupture.¹⁸ The US Food and Drug Administration announced in 2016 that the serious adverse events with fluoroquinolones outweigh the benefits in patients with acute sinusitis, acute bronchitis, and uncomplicated urinary tract infection, and that they should be used only if there are no other options.³⁴

Daptomycin is known to cause elevations of creatine kinase.³⁴ Weekly monitoring is recommended based on postmarketing data reports of elevations in 2.5% of patients; myopathy is a rarer effect, occurring in 0.2% of patients.³⁵

REPRODUCTIVE SYSTEM

Antibiotics have long been reported to interact with oral contraceptives, but the data are not compelling for commonly used antibiotics. The strongest association is with rifampicin, which reduces oral contraceptive efficacy and warrants an alternative mode of contraception.³⁶

BACK TO OUR PATIENT

Antibiotics can have serious adverse effects, and it is important for clinicians to be cognizant of this. Our 60-year-old patient who was taking cefepime and vancomycin for pneumonia developed prolonged atypical absence seizures. When the cefepime was discontinued, his mental status improved, and no other seizures were observed.

At the extreme, this discontent sears our professional being and results in early retirement, change of profession, and, for many, searching for ways to limit clinical practice time—while often saying how much they wish they could “just practice medicine.” Such are some of the manifestations of burnout.

Studies indicate that contributors to burnout are many. And as in all observational studies, the establishment of cause, effect, and degree of codependency is difficult if not impossible to ascertain. Many major changes have temporally coincided with the rise in physician dissatisfaction. One is the increasing corporatization of medicine. In 2016, in some parts of the country, over 40% of physicians were employed by hospitals.¹ Surveys indicate that these employed physicians have a modestly higher degree of dissatisfaction than those in “independent” practices, often citing loss of control of their practice style and increased regulatory demands as contributors to their misery—which is ironic, since the reason many physicians join large hospital-employed groups is to minimize external financial and regulatory pressures.

Astute corporate medical leaders have recognized the burnout issue and are struggling to diminish its negative impact on the healthcare system, patient care, and individual physicians. But many initial approaches have been aimed at soothing the already singed. Health days, yoga sessions, mindfulness classes, and various ways to soften the impact of the EMR on our lives have all been offered up along with other creative and well-intentioned balms. It is not clear to me that any of these address the primary issues contributing to the growing challenge of professional and personal discontent. Some of these approaches may take root and improve a few physicians’ ability to cope. But will that be sufficient to save a generation of skilled and experienced but increasingly disconnected physicians and clinical faculty?

On this landscape, Mangione and Kahn in this issue of the Journal argue for the humanities as part of the solution for what ails us. They cite Sir William Osler, the titan of internal medicine, who a century ago urged physicians to cultivate a strong background in the humanities as a counterweight to the objective science that he also so strongly endorsed and inculcated into the culture at Johns Hopkins. Mangione and Kahn present nascent data suggesting that students who choose to have extra interactions with the arts and humanities exhibit greater resilience, tolerance of ambiguity, and more of the empathetic traits that we desire in physicians, and they posit that these traits will decrease the sense of professional burnout.

We don’t know whether it is the impact of extra exposure to the humanities or the personality of those students who choose to partake of these programs that is the major contributor to the behavioral outcomes, though I suspect it is both. The real question is this: even if we can enhance through greater exposure to the humanities the desired attitudes in our medical students, residents, and young physicians, can we slow the rate of professional dissatisfaction and burnout in them?

To answer this, we need a deeper understanding of the burnout process and whether it will affect younger physicians and physicians currently in training the same way it has affected an older generation of physicians, many of whom have had to face the challenges of coping with the new digital world that our younger colleagues have grown up with. Many of us also have needed to change our practice patterns and expectations. Our younger colleagues may not be faced with the same contextual dissonance that we have had to adjust to in reconciling our (idealistic) image of clinical practice with the pragmatic business of medicine. Their expectations for both are, and will likely remain, quite different.

The next generation of physicians will undoubtedly have their own challenges. They are well familiarized with the digital and virtual world and will likely accept avatar medicine to a far greater degree than we have. But I think the study of the humanities will be of great value to them as well, not necessarily to imbue them with a greater sense of resilience in coping with the digital and science aspects of medicine, but to provide reminders of what Bruce Springsteen has called the “human touch.” Studying the humanities may provide the conceptual reminder of the value of humanness—as we physicians evolve into the world of providing an increasing amount of care via advanced-care providers, shortened real visits, and telemedicine and other virtual consultative visits.

Hopefully, we can indeed find a way to nurture within us Osler’s conceptual tree of medicine that harbors on the same stem the “twin berries” of “the Humanities and Science.”

At the extreme, this discontent sears our professional being and results in early retirement, change of profession, and, for many, searching for ways to limit clinical practice time—while often saying how much they wish they could “just practice medicine.” Such are some of the manifestations of burnout.

Studies indicate that contributors to burnout are many. And as in all observational studies, the establishment of cause, effect, and degree of codependency is difficult if not impossible to ascertain. Many major changes have temporally coincided with the rise in physician dissatisfaction. One is the increasing corporatization of medicine. In 2016, in some parts of the country, over 40% of physicians were employed by hospitals.¹ Surveys indicate that these employed physicians have a modestly higher degree of dissatisfaction than those in “independent” practices, often citing loss of control of their practice style and increased regulatory demands as contributors to their misery—which is ironic, since the reason many physicians join large hospital-employed groups is to minimize external financial and regulatory pressures.

Astute corporate medical leaders have recognized the burnout issue and are struggling to diminish its negative impact on the healthcare system, patient care, and individual physicians. But many initial approaches have been aimed at soothing the already singed. Health days, yoga sessions, mindfulness classes, and various ways to soften the impact of the EMR on our lives have all been offered up along with other creative and well-intentioned balms. It is not clear to me that any of these address the primary issues contributing to the growing challenge of professional and personal discontent. Some of these approaches may take root and improve a few physicians’ ability to cope. But will that be sufficient to save a generation of skilled and experienced but increasingly disconnected physicians and clinical faculty?

On this landscape, Mangione and Kahn in this issue of the Journal argue for the humanities as part of the solution for what ails us. They cite Sir William Osler, the titan of internal medicine, who a century ago urged physicians to cultivate a strong background in the humanities as a counterweight to the objective science that he also so strongly endorsed and inculcated into the culture at Johns Hopkins. Mangione and Kahn present nascent data suggesting that students who choose to have extra interactions with the arts and humanities exhibit greater resilience, tolerance of ambiguity, and more of the empathetic traits that we desire in physicians, and they posit that these traits will decrease the sense of professional burnout.

We don’t know whether it is the impact of extra exposure to the humanities or the personality of those students who choose to partake of these programs that is the major contributor to the behavioral outcomes, though I suspect it is both. The real question is this: even if we can enhance through greater exposure to the humanities the desired attitudes in our medical students, residents, and young physicians, can we slow the rate of professional dissatisfaction and burnout in them?

To answer this, we need a deeper understanding of the burnout process and whether it will affect younger physicians and physicians currently in training the same way it has affected an older generation of physicians, many of whom have had to face the challenges of coping with the new digital world that our younger colleagues have grown up with. Many of us also have needed to change our practice patterns and expectations. Our younger colleagues may not be faced with the same contextual dissonance that we have had to adjust to in reconciling our (idealistic) image of clinical practice with the pragmatic business of medicine. Their expectations for both are, and will likely remain, quite different.

The next generation of physicians will undoubtedly have their own challenges. They are well familiarized with the digital and virtual world and will likely accept avatar medicine to a far greater degree than we have. But I think the study of the humanities will be of great value to them as well, not necessarily to imbue them with a greater sense of resilience in coping with the digital and science aspects of medicine, but to provide reminders of what Bruce Springsteen has called the “human touch.” Studying the humanities may provide the conceptual reminder of the value of humanness—as we physicians evolve into the world of providing an increasing amount of care via advanced-care providers, shortened real visits, and telemedicine and other virtual consultative visits.

Hopefully, we can indeed find a way to nurture within us Osler’s conceptual tree of medicine that harbors on the same stem the “twin berries” of “the Humanities and Science.”

At the extreme, this discontent sears our professional being and results in early retirement, change of profession, and, for many, searching for ways to limit clinical practice time—while often saying how much they wish they could “just practice medicine.” Such are some of the manifestations of burnout.

Studies indicate that contributors to burnout are many. And as in all observational studies, the establishment of cause, effect, and degree of codependency is difficult if not impossible to ascertain. Many major changes have temporally coincided with the rise in physician dissatisfaction. One is the increasing corporatization of medicine. In 2016, in some parts of the country, over 40% of physicians were employed by hospitals.¹ Surveys indicate that these employed physicians have a modestly higher degree of dissatisfaction than those in “independent” practices, often citing loss of control of their practice style and increased regulatory demands as contributors to their misery—which is ironic, since the reason many physicians join large hospital-employed groups is to minimize external financial and regulatory pressures.

Astute corporate medical leaders have recognized the burnout issue and are struggling to diminish its negative impact on the healthcare system, patient care, and individual physicians. But many initial approaches have been aimed at soothing the already singed. Health days, yoga sessions, mindfulness classes, and various ways to soften the impact of the EMR on our lives have all been offered up along with other creative and well-intentioned balms. It is not clear to me that any of these address the primary issues contributing to the growing challenge of professional and personal discontent. Some of these approaches may take root and improve a few physicians’ ability to cope. But will that be sufficient to save a generation of skilled and experienced but increasingly disconnected physicians and clinical faculty?

On this landscape, Mangione and Kahn in this issue of the Journal argue for the humanities as part of the solution for what ails us. They cite Sir William Osler, the titan of internal medicine, who a century ago urged physicians to cultivate a strong background in the humanities as a counterweight to the objective science that he also so strongly endorsed and inculcated into the culture at Johns Hopkins. Mangione and Kahn present nascent data suggesting that students who choose to have extra interactions with the arts and humanities exhibit greater resilience, tolerance of ambiguity, and more of the empathetic traits that we desire in physicians, and they posit that these traits will decrease the sense of professional burnout.

We don’t know whether it is the impact of extra exposure to the humanities or the personality of those students who choose to partake of these programs that is the major contributor to the behavioral outcomes, though I suspect it is both. The real question is this: even if we can enhance through greater exposure to the humanities the desired attitudes in our medical students, residents, and young physicians, can we slow the rate of professional dissatisfaction and burnout in them?

To answer this, we need a deeper understanding of the burnout process and whether it will affect younger physicians and physicians currently in training the same way it has affected an older generation of physicians, many of whom have had to face the challenges of coping with the new digital world that our younger colleagues have grown up with. Many of us also have needed to change our practice patterns and expectations. Our younger colleagues may not be faced with the same contextual dissonance that we have had to adjust to in reconciling our (idealistic) image of clinical practice with the pragmatic business of medicine. Their expectations for both are, and will likely remain, quite different.

The next generation of physicians will undoubtedly have their own challenges. They are well familiarized with the digital and virtual world and will likely accept avatar medicine to a far greater degree than we have. But I think the study of the humanities will be of great value to them as well, not necessarily to imbue them with a greater sense of resilience in coping with the digital and science aspects of medicine, but to provide reminders of what Bruce Springsteen has called the “human touch.” Studying the humanities may provide the conceptual reminder of the value of humanness—as we physicians evolve into the world of providing an increasing amount of care via advanced-care providers, shortened real visits, and telemedicine and other virtual consultative visits.

Hopefully, we can indeed find a way to nurture within us Osler’s conceptual tree of medicine that harbors on the same stem the “twin berries” of “the Humanities and Science.”

A 40-year-old man with type 1 diabetes mellitus and recurrent renal calculi presented to the emergency department with nausea, vomiting, and abdominal pain for the past day. He had been checking his blood glucose level regularly, and it had usually been within the normal range until 2 or 3 days previously, when he stopped taking his insulin because he ran out and could not afford to buy more.

He said he initially vomited clear mucus but then had 2 episodes of black vomit. His abdominal pain was diffuse but more intense in his flanks. He said he had never had nausea or vomiting before this episode.

In the emergency department, his heart rate was 136 beats per minute and respiratory rate 24 breaths per minute. He appeared to be in mild distress, and physical examination revealed a distended abdomen, decreased bowel sounds on auscultation, tympanic sound elicited by percussion, and diffuse abdominal tenderness to palpation without rebound tenderness or rigidity. His blood glucose level was 993 mg/dL, and his anion gap was 36 mmol/L.

The patient was treated with hydration, insulin, and a nasogastric tube to relieve the pressure. The following day, his symptoms had significantly improved, his abdomen was less distended, his bowel sounds had returned, and his plasma glucose levels were in the normal range. The nasogastric tube was removed after he started to have bowel movements; he was given liquids by mouth and eventually solid food. Since his condition had significantly improved and he had started to have bowel movements, no follow-up imaging was done. The next day, he was symptom-free, his laboratory values were normal, and he was discharged home.

GASTROPARESIS

Gastroparesis is defined by delayed gastric emptying in the absence of a mechanical obstruction, with symptoms of nausea, vomiting, bloating, and abdominal pain. Most commonly it is idiopathic or caused by long-standing uncontrolled diabetes.

Diabetic gastroparesis is thought to result from impaired neural control of gastric function. Damage to the pacemaker interstitial cells of Cajal and underlying smooth muscle may be contributing factors.¹ It is usually chronic, with a mean duration of symptoms of 26.5 months.² However, acute gastroparesis can occur after an acute elevation in the plasma glucose concentration, which can affect gastric sensory and motor function³ via relaxation of the proximal stomach, decrease in antral pressure waves, and increase in pyloric pressure waves.⁴

Patients with diabetic ketoacidosis often present with symptoms similar to those of gastroparesis, including nausea, vomiting, and abdominal pain.⁵ But acute gastroparesis can coexist with diabetic ketoacidosis, as in our patient, and the gastroparesis can go undiagnosed, since imaging studies are not routinely done for diabetic ketoacidosis unless there is another reason—as in our patient.         

More study is needed to answer questions on long-term outcomes for patients presenting with acute gastroparesis: Do they develop chronic gastroparesis? And is there is a correlation with progression of neuropathy?

The diagnosis usually requires a high level of suspicion in patients with nausea, vomiting, fullness, abdominal pain, and bloating; exclusion of gastric outlet obstruction by a mass or antral stenosis; and evidence of delayed gastric emptying. Gastric outlet obstruction can be ruled out by endoscopy, abdominal CT, or magnetic resonance enterography. Delayed gastric emptying can be quantified with scintigraphy and endoscopy. In our patient, gastroparesis was diagnosed on the basis of the clinical symptoms and CT findings.

Treatment is usually directed at symptoms, with better glycemic control and dietary modification for moderate cases, and prokinetics and a gastrostomy tube for severe cases.

TAKE-HOME POINTS

• Gastroparesis is usually chronic but can present acutely with acute severe hyperglycemia.
• Gastrointestinal tract motor function is affected by plasma glucose levels and can change over brief intervals.
• Diabetic ketoacidosis symptoms can mask acute gastroparesis, as imaging studies are not routinely done.
• Acute gastroparesis can be diagnosed clinically along with abdominal CT or endoscopy to rule out gastric outlet obstruction.
• Acute gastroparesis caused by diabetic ketoacidosis can resolve promptly with tight control of plasma glucose levels, anion gap closing, and nasogastric tube placement.

A 40-year-old man with type 1 diabetes mellitus and recurrent renal calculi presented to the emergency department with nausea, vomiting, and abdominal pain for the past day. He had been checking his blood glucose level regularly, and it had usually been within the normal range until 2 or 3 days previously, when he stopped taking his insulin because he ran out and could not afford to buy more.

He said he initially vomited clear mucus but then had 2 episodes of black vomit. His abdominal pain was diffuse but more intense in his flanks. He said he had never had nausea or vomiting before this episode.

In the emergency department, his heart rate was 136 beats per minute and respiratory rate 24 breaths per minute. He appeared to be in mild distress, and physical examination revealed a distended abdomen, decreased bowel sounds on auscultation, tympanic sound elicited by percussion, and diffuse abdominal tenderness to palpation without rebound tenderness or rigidity. His blood glucose level was 993 mg/dL, and his anion gap was 36 mmol/L.

The patient was treated with hydration, insulin, and a nasogastric tube to relieve the pressure. The following day, his symptoms had significantly improved, his abdomen was less distended, his bowel sounds had returned, and his plasma glucose levels were in the normal range. The nasogastric tube was removed after he started to have bowel movements; he was given liquids by mouth and eventually solid food. Since his condition had significantly improved and he had started to have bowel movements, no follow-up imaging was done. The next day, he was symptom-free, his laboratory values were normal, and he was discharged home.

GASTROPARESIS

Gastroparesis is defined by delayed gastric emptying in the absence of a mechanical obstruction, with symptoms of nausea, vomiting, bloating, and abdominal pain. Most commonly it is idiopathic or caused by long-standing uncontrolled diabetes.

Diabetic gastroparesis is thought to result from impaired neural control of gastric function. Damage to the pacemaker interstitial cells of Cajal and underlying smooth muscle may be contributing factors.¹ It is usually chronic, with a mean duration of symptoms of 26.5 months.² However, acute gastroparesis can occur after an acute elevation in the plasma glucose concentration, which can affect gastric sensory and motor function³ via relaxation of the proximal stomach, decrease in antral pressure waves, and increase in pyloric pressure waves.⁴

Patients with diabetic ketoacidosis often present with symptoms similar to those of gastroparesis, including nausea, vomiting, and abdominal pain.⁵ But acute gastroparesis can coexist with diabetic ketoacidosis, as in our patient, and the gastroparesis can go undiagnosed, since imaging studies are not routinely done for diabetic ketoacidosis unless there is another reason—as in our patient.         

More study is needed to answer questions on long-term outcomes for patients presenting with acute gastroparesis: Do they develop chronic gastroparesis? And is there is a correlation with progression of neuropathy?

The diagnosis usually requires a high level of suspicion in patients with nausea, vomiting, fullness, abdominal pain, and bloating; exclusion of gastric outlet obstruction by a mass or antral stenosis; and evidence of delayed gastric emptying. Gastric outlet obstruction can be ruled out by endoscopy, abdominal CT, or magnetic resonance enterography. Delayed gastric emptying can be quantified with scintigraphy and endoscopy. In our patient, gastroparesis was diagnosed on the basis of the clinical symptoms and CT findings.

Treatment is usually directed at symptoms, with better glycemic control and dietary modification for moderate cases, and prokinetics and a gastrostomy tube for severe cases.

TAKE-HOME POINTS

• Gastroparesis is usually chronic but can present acutely with acute severe hyperglycemia.
• Gastrointestinal tract motor function is affected by plasma glucose levels and can change over brief intervals.
• Diabetic ketoacidosis symptoms can mask acute gastroparesis, as imaging studies are not routinely done.
• Acute gastroparesis can be diagnosed clinically along with abdominal CT or endoscopy to rule out gastric outlet obstruction.
• Acute gastroparesis caused by diabetic ketoacidosis can resolve promptly with tight control of plasma glucose levels, anion gap closing, and nasogastric tube placement.

A 40-year-old man with type 1 diabetes mellitus and recurrent renal calculi presented to the emergency department with nausea, vomiting, and abdominal pain for the past day. He had been checking his blood glucose level regularly, and it had usually been within the normal range until 2 or 3 days previously, when he stopped taking his insulin because he ran out and could not afford to buy more.

He said he initially vomited clear mucus but then had 2 episodes of black vomit. His abdominal pain was diffuse but more intense in his flanks. He said he had never had nausea or vomiting before this episode.

In the emergency department, his heart rate was 136 beats per minute and respiratory rate 24 breaths per minute. He appeared to be in mild distress, and physical examination revealed a distended abdomen, decreased bowel sounds on auscultation, tympanic sound elicited by percussion, and diffuse abdominal tenderness to palpation without rebound tenderness or rigidity. His blood glucose level was 993 mg/dL, and his anion gap was 36 mmol/L.

The patient was treated with hydration, insulin, and a nasogastric tube to relieve the pressure. The following day, his symptoms had significantly improved, his abdomen was less distended, his bowel sounds had returned, and his plasma glucose levels were in the normal range. The nasogastric tube was removed after he started to have bowel movements; he was given liquids by mouth and eventually solid food. Since his condition had significantly improved and he had started to have bowel movements, no follow-up imaging was done. The next day, he was symptom-free, his laboratory values were normal, and he was discharged home.

GASTROPARESIS

Gastroparesis is defined by delayed gastric emptying in the absence of a mechanical obstruction, with symptoms of nausea, vomiting, bloating, and abdominal pain. Most commonly it is idiopathic or caused by long-standing uncontrolled diabetes.

Diabetic gastroparesis is thought to result from impaired neural control of gastric function. Damage to the pacemaker interstitial cells of Cajal and underlying smooth muscle may be contributing factors.¹ It is usually chronic, with a mean duration of symptoms of 26.5 months.² However, acute gastroparesis can occur after an acute elevation in the plasma glucose concentration, which can affect gastric sensory and motor function³ via relaxation of the proximal stomach, decrease in antral pressure waves, and increase in pyloric pressure waves.⁴

Patients with diabetic ketoacidosis often present with symptoms similar to those of gastroparesis, including nausea, vomiting, and abdominal pain.⁵ But acute gastroparesis can coexist with diabetic ketoacidosis, as in our patient, and the gastroparesis can go undiagnosed, since imaging studies are not routinely done for diabetic ketoacidosis unless there is another reason—as in our patient.         

More study is needed to answer questions on long-term outcomes for patients presenting with acute gastroparesis: Do they develop chronic gastroparesis? And is there is a correlation with progression of neuropathy?

The diagnosis usually requires a high level of suspicion in patients with nausea, vomiting, fullness, abdominal pain, and bloating; exclusion of gastric outlet obstruction by a mass or antral stenosis; and evidence of delayed gastric emptying. Gastric outlet obstruction can be ruled out by endoscopy, abdominal CT, or magnetic resonance enterography. Delayed gastric emptying can be quantified with scintigraphy and endoscopy. In our patient, gastroparesis was diagnosed on the basis of the clinical symptoms and CT findings.

Treatment is usually directed at symptoms, with better glycemic control and dietary modification for moderate cases, and prokinetics and a gastrostomy tube for severe cases.

TAKE-HOME POINTS

• Gastroparesis is usually chronic but can present acutely with acute severe hyperglycemia.
• Gastrointestinal tract motor function is affected by plasma glucose levels and can change over brief intervals.
• Diabetic ketoacidosis symptoms can mask acute gastroparesis, as imaging studies are not routinely done.
• Acute gastroparesis can be diagnosed clinically along with abdominal CT or endoscopy to rule out gastric outlet obstruction.
• Acute gastroparesis caused by diabetic ketoacidosis can resolve promptly with tight control of plasma glucose levels, anion gap closing, and nasogastric tube placement.

Acute agitation in the pregnant patient should be treated as an obstetric emergency, as it jeopardizes the safety of the patient and fetus, as well as others in the emergency room. Uncontrolled agitation is associated with obstetric complications such as preterm delivery, placental abnormalities, postnatal death, and spontaneous abortion.¹

Current data on the reproductive safety of drugs commonly used to treat acute agitation—benzodiazepines, typical (first-generation) antipsychotics, atypical (second-generation) antipsychotics, and diphenhydramine—suggest no increase in risk beyond the 2% to 3% risk of congenital malformations in the general population when used in the first trimester.^2,3

FOCUS OF THE EMERGENCY EVALUATION

Agitation is defined as the physical manifestation of internal distress, due to an underlying medical condition such as delirium or to a psychiatric condition such as acute intoxication or withdrawal, psychosis, mania, or personality disorder.⁴

For the agitated pregnant woman who is not belligerent at presentation, triage should start with a basic assessment of airways, breathing, and circulation, as well as vital signs and glucose level.⁵ A thorough medical history and a description of events leading to the presentation, obtained from the patient or the patient’s family or friends, are vital for narrowing the diagnosis and deciding treatment.

The initial evaluation should include consideration of delirium, trauma, intracranial hemorrhage, coagulopathy, thrombocytopenia, amniotic and venous thromboembolism, hypoxia and hypercapnia, and signs and symptoms of intoxication or withdrawal from substances such as alcohol, cocaine, phencyclidine, methamphetamine, and substituted cathinones (“bath salts”). From 20 weeks of gestation to 6 weeks postpartum, eclampsia should also be considered in the differential diagnosis.¹ Ruling out these conditions is important since the management of each differs vastly from the protocol for agitation secondary to psychosis, mania, or delirium.

NEW SYSTEM TO DETERMINE RISK DURING PREGNANCY, LACTATION

The US Food and Drug Administration (FDA) has discontinued its pregnancy category labeling system that used the letters A, B, C, D, and X to convey reproductive and lactation safety. The new system, established under the FDA Pregnancy and Lactation Labeling Rule,⁶ provides descriptive, up-to-date explanations of risk, as well as previously absent context regarding baseline risk for major malformations in the general population to help with informed decision-making.⁷ This allows the healthcare provider to interpret the risk for an individual patient.

FIRST-GENERATION ANTIPSYCHOTICS SAFE, EFFECTIVE IN PREGNANCY

Reproductive safety of first-generation (ie, typical) neuroleptics such as haloperidol is supported by extensive data accumulated over the past 50 years.^2,3,8 No significant teratogenic effect has been documented with this drug class,⁷ although a 1996 meta-analysis found a small increase in the relative risk of congenital malformations in offspring exposed to low-potency antipsychotics compared with those exposed to high-potency antipsychotics.²

In general, mid- and high-potency antipsychotics (eg, haloperidol, perphenazine) are often recommended because they are less likely to have associated sedative or hypotensive effects than low-potency antipsychotics (eg, chlorpromazine, perphenazine), which may be a significant consideration for a pregnant patient.^2,8

There is a theoretical risk of neonatal extrapyramidal symptoms with exposure to first-generation antipsychotics in the third trimester, but the data to support this are from sparse case reports and small observational cohorts.⁹

NEWER ANTIPSYCHOTICS ALSO SAFE IN PREGNANCY

Newer antipsychotics such as the second-generation antipsychotics, available since the mid-1990s, are increasingly used as primary or adjunctive therapy across a wide range of psychiatric disorders.¹⁰ Recent data from large, prospective cohort studies investigating reproductive safety of these agents are reassuring, with no specific patterns of organ malformation.^11,12

DIPHENHYDRAMINE

Recent studies of antihistamines such as diphenhydramine have not reported any risk of major malformations with first-trimester exposure to antihistamines.^13,14 Dose-dependent anticholinergic adverse effects of antihistamines can induce or exacerbate delirium and agitation, although these effects are classically seen in elderly, nonpregnant patients.¹⁵ Thus, given the paucity of adverse effects and the low risk, diphenhydramine is considered safe to use in pregnancy.¹³

Benzodiazepines are not contraindicated for the treatment of acute agitation in pregnancy.¹⁶ Reproductive safety data from meta-analyses and large population-based cohort studies have found no evidence of increased risk of major malformations in neonates born to mothers on prescription benzodiazepines in the first trimester.^17,18 While third-trimester exposure to benzodiazepines has been associated with “floppy-baby” syndrome and neonatal withdrawal syndrome,¹⁶ these are more likely to occur in women on long-term prescription benzodiazepine therapy. No study has yet assessed the risk of these outcomes with a 1-time acute exposure in the emergency department; however, the risk is likely minimal given the aforementioned data observed in women on long-term prescription benzodiazepine therapy.

STEPWISE MANAGEMENT OF AGITATION IN PREGNANCY

If untreated, agitation in pregnancy is independently associated with outcomes that include premature delivery, low birth weight, growth retardation, postnatal death, and spontaneous abortion.¹ The risk of these outcomes greatly outweighs any potential risk from psychotropic medications during pregnancy.

Nevertheless, intervention should progress in a stepwise manner, starting with the least restrictive and progressing toward more restrictive interventions, including pharmacotherapy, use of a seclusion room, and physical restraints (Figure 1).^4,19

Before medications are considered, attempts should be made to engage with and “de-escalate” the patient in a safe, nonstimulating environment.¹⁹ If this approach is not effective, the patient should be offered oral medications to help with her agitation. However, if the patient’s behavior continues to escalate, presenting a danger to herself or staff, the use of emergency medications is clearly indicated. Providers should succinctly inform the patient of the need for immediate intervention.

If the patient has had a good response in the past to one of these medications or is currently taking one as needed, the same medication should be offered. If the patient has never been treated for agitation, it is important to consider the presenting symptoms, differential diagnosis, and the route and rapidity of administration of medication. If the patient has experienced a fall or other trauma, confirming a viable fetal heart rate between 10 to 22 weeks of gestation with Doppler ultrasonography and obstetric consultation should be considered.

DRUG THERAPY RECOMMENDATIONS

Mild to moderate agitation in pregnancy should be managed conservatively with diphenhydramine. Other options include a benzodiazepine, particularly lorazepam, if alcohol withdrawal is suspected. A second-generation antipsychotic such as olanzapine in a rapidly dissolving form or ziprasidone is another option if a rapid response is required.²⁰Table 1 provides a summary of pharmacotherapy recommendations.

Severe agitation may require a combination of agents. A commonly used, safe regimen—colloquially called the “B52 bomb”—is haloperidol 5 mg, lorazepam 2 mg, and diphenhydramine 25 to 50 mg for prophylaxis of dystonia.²⁰

The patient’s response should be monitored closely, as dosing may require modification as a result of pregnancy-related changes in drug distribution, metabolism, and clearance.²¹

Although no study to our knowledge has assessed risk associated with 1-time exposure to any of these classes of medications in pregnant women, the aforementioned data on long-term exposure provide reassurance that single exposure in emergency departments likely has little or no effect for the developing fetus.

PHYSICAL RESTRAINTS FOR AGITATION IN PREGNANCY

Physical restraints along with emergency medications (ie, chemical restraint) may be indicated when the patient poses a danger to herself or others. In some cases, both types of restraint may be required, whether in the emergency room or an inpatient setting.

However, during the second and third trimesters, physical restraints such as 4-point restraints may predispose the patient to inferior vena cava compression syndrome and compromise placental blood flow.⁴ Therefore, pregnant patients after 20 weeks of gestation should be positioned in the left lateral decubitus position, with the right hip positioned 10 to 12 cm off the bed with pillows or blankets. And when restraints are used in pregnant patients, frequent checking of vital signs and physical assessment is needed to mitigate risks.⁴

Acute agitation in the pregnant patient should be treated as an obstetric emergency, as it jeopardizes the safety of the patient and fetus, as well as others in the emergency room. Uncontrolled agitation is associated with obstetric complications such as preterm delivery, placental abnormalities, postnatal death, and spontaneous abortion.¹

Current data on the reproductive safety of drugs commonly used to treat acute agitation—benzodiazepines, typical (first-generation) antipsychotics, atypical (second-generation) antipsychotics, and diphenhydramine—suggest no increase in risk beyond the 2% to 3% risk of congenital malformations in the general population when used in the first trimester.^2,3

FOCUS OF THE EMERGENCY EVALUATION

Agitation is defined as the physical manifestation of internal distress, due to an underlying medical condition such as delirium or to a psychiatric condition such as acute intoxication or withdrawal, psychosis, mania, or personality disorder.⁴

For the agitated pregnant woman who is not belligerent at presentation, triage should start with a basic assessment of airways, breathing, and circulation, as well as vital signs and glucose level.⁵ A thorough medical history and a description of events leading to the presentation, obtained from the patient or the patient’s family or friends, are vital for narrowing the diagnosis and deciding treatment.

The initial evaluation should include consideration of delirium, trauma, intracranial hemorrhage, coagulopathy, thrombocytopenia, amniotic and venous thromboembolism, hypoxia and hypercapnia, and signs and symptoms of intoxication or withdrawal from substances such as alcohol, cocaine, phencyclidine, methamphetamine, and substituted cathinones (“bath salts”). From 20 weeks of gestation to 6 weeks postpartum, eclampsia should also be considered in the differential diagnosis.¹ Ruling out these conditions is important since the management of each differs vastly from the protocol for agitation secondary to psychosis, mania, or delirium.

NEW SYSTEM TO DETERMINE RISK DURING PREGNANCY, LACTATION

The US Food and Drug Administration (FDA) has discontinued its pregnancy category labeling system that used the letters A, B, C, D, and X to convey reproductive and lactation safety. The new system, established under the FDA Pregnancy and Lactation Labeling Rule,⁶ provides descriptive, up-to-date explanations of risk, as well as previously absent context regarding baseline risk for major malformations in the general population to help with informed decision-making.⁷ This allows the healthcare provider to interpret the risk for an individual patient.

FIRST-GENERATION ANTIPSYCHOTICS SAFE, EFFECTIVE IN PREGNANCY

Reproductive safety of first-generation (ie, typical) neuroleptics such as haloperidol is supported by extensive data accumulated over the past 50 years.^2,3,8 No significant teratogenic effect has been documented with this drug class,⁷ although a 1996 meta-analysis found a small increase in the relative risk of congenital malformations in offspring exposed to low-potency antipsychotics compared with those exposed to high-potency antipsychotics.²

In general, mid- and high-potency antipsychotics (eg, haloperidol, perphenazine) are often recommended because they are less likely to have associated sedative or hypotensive effects than low-potency antipsychotics (eg, chlorpromazine, perphenazine), which may be a significant consideration for a pregnant patient.^2,8

There is a theoretical risk of neonatal extrapyramidal symptoms with exposure to first-generation antipsychotics in the third trimester, but the data to support this are from sparse case reports and small observational cohorts.⁹

NEWER ANTIPSYCHOTICS ALSO SAFE IN PREGNANCY

Newer antipsychotics such as the second-generation antipsychotics, available since the mid-1990s, are increasingly used as primary or adjunctive therapy across a wide range of psychiatric disorders.¹⁰ Recent data from large, prospective cohort studies investigating reproductive safety of these agents are reassuring, with no specific patterns of organ malformation.^11,12

DIPHENHYDRAMINE

Recent studies of antihistamines such as diphenhydramine have not reported any risk of major malformations with first-trimester exposure to antihistamines.^13,14 Dose-dependent anticholinergic adverse effects of antihistamines can induce or exacerbate delirium and agitation, although these effects are classically seen in elderly, nonpregnant patients.¹⁵ Thus, given the paucity of adverse effects and the low risk, diphenhydramine is considered safe to use in pregnancy.¹³

Benzodiazepines are not contraindicated for the treatment of acute agitation in pregnancy.¹⁶ Reproductive safety data from meta-analyses and large population-based cohort studies have found no evidence of increased risk of major malformations in neonates born to mothers on prescription benzodiazepines in the first trimester.^17,18 While third-trimester exposure to benzodiazepines has been associated with “floppy-baby” syndrome and neonatal withdrawal syndrome,¹⁶ these are more likely to occur in women on long-term prescription benzodiazepine therapy. No study has yet assessed the risk of these outcomes with a 1-time acute exposure in the emergency department; however, the risk is likely minimal given the aforementioned data observed in women on long-term prescription benzodiazepine therapy.

STEPWISE MANAGEMENT OF AGITATION IN PREGNANCY

If untreated, agitation in pregnancy is independently associated with outcomes that include premature delivery, low birth weight, growth retardation, postnatal death, and spontaneous abortion.¹ The risk of these outcomes greatly outweighs any potential risk from psychotropic medications during pregnancy.

Nevertheless, intervention should progress in a stepwise manner, starting with the least restrictive and progressing toward more restrictive interventions, including pharmacotherapy, use of a seclusion room, and physical restraints (Figure 1).^4,19

Before medications are considered, attempts should be made to engage with and “de-escalate” the patient in a safe, nonstimulating environment.¹⁹ If this approach is not effective, the patient should be offered oral medications to help with her agitation. However, if the patient’s behavior continues to escalate, presenting a danger to herself or staff, the use of emergency medications is clearly indicated. Providers should succinctly inform the patient of the need for immediate intervention.

If the patient has had a good response in the past to one of these medications or is currently taking one as needed, the same medication should be offered. If the patient has never been treated for agitation, it is important to consider the presenting symptoms, differential diagnosis, and the route and rapidity of administration of medication. If the patient has experienced a fall or other trauma, confirming a viable fetal heart rate between 10 to 22 weeks of gestation with Doppler ultrasonography and obstetric consultation should be considered.

DRUG THERAPY RECOMMENDATIONS

Mild to moderate agitation in pregnancy should be managed conservatively with diphenhydramine. Other options include a benzodiazepine, particularly lorazepam, if alcohol withdrawal is suspected. A second-generation antipsychotic such as olanzapine in a rapidly dissolving form or ziprasidone is another option if a rapid response is required.²⁰Table 1 provides a summary of pharmacotherapy recommendations.

Severe agitation may require a combination of agents. A commonly used, safe regimen—colloquially called the “B52 bomb”—is haloperidol 5 mg, lorazepam 2 mg, and diphenhydramine 25 to 50 mg for prophylaxis of dystonia.²⁰

The patient’s response should be monitored closely, as dosing may require modification as a result of pregnancy-related changes in drug distribution, metabolism, and clearance.²¹

Although no study to our knowledge has assessed risk associated with 1-time exposure to any of these classes of medications in pregnant women, the aforementioned data on long-term exposure provide reassurance that single exposure in emergency departments likely has little or no effect for the developing fetus.

PHYSICAL RESTRAINTS FOR AGITATION IN PREGNANCY

Physical restraints along with emergency medications (ie, chemical restraint) may be indicated when the patient poses a danger to herself or others. In some cases, both types of restraint may be required, whether in the emergency room or an inpatient setting.

However, during the second and third trimesters, physical restraints such as 4-point restraints may predispose the patient to inferior vena cava compression syndrome and compromise placental blood flow.⁴ Therefore, pregnant patients after 20 weeks of gestation should be positioned in the left lateral decubitus position, with the right hip positioned 10 to 12 cm off the bed with pillows or blankets. And when restraints are used in pregnant patients, frequent checking of vital signs and physical assessment is needed to mitigate risks.⁴

Acute agitation in the pregnant patient should be treated as an obstetric emergency, as it jeopardizes the safety of the patient and fetus, as well as others in the emergency room. Uncontrolled agitation is associated with obstetric complications such as preterm delivery, placental abnormalities, postnatal death, and spontaneous abortion.¹

Current data on the reproductive safety of drugs commonly used to treat acute agitation—benzodiazepines, typical (first-generation) antipsychotics, atypical (second-generation) antipsychotics, and diphenhydramine—suggest no increase in risk beyond the 2% to 3% risk of congenital malformations in the general population when used in the first trimester.^2,3

FOCUS OF THE EMERGENCY EVALUATION

Agitation is defined as the physical manifestation of internal distress, due to an underlying medical condition such as delirium or to a psychiatric condition such as acute intoxication or withdrawal, psychosis, mania, or personality disorder.⁴

For the agitated pregnant woman who is not belligerent at presentation, triage should start with a basic assessment of airways, breathing, and circulation, as well as vital signs and glucose level.⁵ A thorough medical history and a description of events leading to the presentation, obtained from the patient or the patient’s family or friends, are vital for narrowing the diagnosis and deciding treatment.

The initial evaluation should include consideration of delirium, trauma, intracranial hemorrhage, coagulopathy, thrombocytopenia, amniotic and venous thromboembolism, hypoxia and hypercapnia, and signs and symptoms of intoxication or withdrawal from substances such as alcohol, cocaine, phencyclidine, methamphetamine, and substituted cathinones (“bath salts”). From 20 weeks of gestation to 6 weeks postpartum, eclampsia should also be considered in the differential diagnosis.¹ Ruling out these conditions is important since the management of each differs vastly from the protocol for agitation secondary to psychosis, mania, or delirium.

NEW SYSTEM TO DETERMINE RISK DURING PREGNANCY, LACTATION

The US Food and Drug Administration (FDA) has discontinued its pregnancy category labeling system that used the letters A, B, C, D, and X to convey reproductive and lactation safety. The new system, established under the FDA Pregnancy and Lactation Labeling Rule,⁶ provides descriptive, up-to-date explanations of risk, as well as previously absent context regarding baseline risk for major malformations in the general population to help with informed decision-making.⁷ This allows the healthcare provider to interpret the risk for an individual patient.

FIRST-GENERATION ANTIPSYCHOTICS SAFE, EFFECTIVE IN PREGNANCY

Reproductive safety of first-generation (ie, typical) neuroleptics such as haloperidol is supported by extensive data accumulated over the past 50 years.^2,3,8 No significant teratogenic effect has been documented with this drug class,⁷ although a 1996 meta-analysis found a small increase in the relative risk of congenital malformations in offspring exposed to low-potency antipsychotics compared with those exposed to high-potency antipsychotics.²

In general, mid- and high-potency antipsychotics (eg, haloperidol, perphenazine) are often recommended because they are less likely to have associated sedative or hypotensive effects than low-potency antipsychotics (eg, chlorpromazine, perphenazine), which may be a significant consideration for a pregnant patient.^2,8

There is a theoretical risk of neonatal extrapyramidal symptoms with exposure to first-generation antipsychotics in the third trimester, but the data to support this are from sparse case reports and small observational cohorts.⁹

NEWER ANTIPSYCHOTICS ALSO SAFE IN PREGNANCY

Newer antipsychotics such as the second-generation antipsychotics, available since the mid-1990s, are increasingly used as primary or adjunctive therapy across a wide range of psychiatric disorders.¹⁰ Recent data from large, prospective cohort studies investigating reproductive safety of these agents are reassuring, with no specific patterns of organ malformation.^11,12

DIPHENHYDRAMINE

Recent studies of antihistamines such as diphenhydramine have not reported any risk of major malformations with first-trimester exposure to antihistamines.^13,14 Dose-dependent anticholinergic adverse effects of antihistamines can induce or exacerbate delirium and agitation, although these effects are classically seen in elderly, nonpregnant patients.¹⁵ Thus, given the paucity of adverse effects and the low risk, diphenhydramine is considered safe to use in pregnancy.¹³

Benzodiazepines are not contraindicated for the treatment of acute agitation in pregnancy.¹⁶ Reproductive safety data from meta-analyses and large population-based cohort studies have found no evidence of increased risk of major malformations in neonates born to mothers on prescription benzodiazepines in the first trimester.^17,18 While third-trimester exposure to benzodiazepines has been associated with “floppy-baby” syndrome and neonatal withdrawal syndrome,¹⁶ these are more likely to occur in women on long-term prescription benzodiazepine therapy. No study has yet assessed the risk of these outcomes with a 1-time acute exposure in the emergency department; however, the risk is likely minimal given the aforementioned data observed in women on long-term prescription benzodiazepine therapy.

STEPWISE MANAGEMENT OF AGITATION IN PREGNANCY

If untreated, agitation in pregnancy is independently associated with outcomes that include premature delivery, low birth weight, growth retardation, postnatal death, and spontaneous abortion.¹ The risk of these outcomes greatly outweighs any potential risk from psychotropic medications during pregnancy.

Nevertheless, intervention should progress in a stepwise manner, starting with the least restrictive and progressing toward more restrictive interventions, including pharmacotherapy, use of a seclusion room, and physical restraints (Figure 1).^4,19

Before medications are considered, attempts should be made to engage with and “de-escalate” the patient in a safe, nonstimulating environment.¹⁹ If this approach is not effective, the patient should be offered oral medications to help with her agitation. However, if the patient’s behavior continues to escalate, presenting a danger to herself or staff, the use of emergency medications is clearly indicated. Providers should succinctly inform the patient of the need for immediate intervention.

If the patient has had a good response in the past to one of these medications or is currently taking one as needed, the same medication should be offered. If the patient has never been treated for agitation, it is important to consider the presenting symptoms, differential diagnosis, and the route and rapidity of administration of medication. If the patient has experienced a fall or other trauma, confirming a viable fetal heart rate between 10 to 22 weeks of gestation with Doppler ultrasonography and obstetric consultation should be considered.

DRUG THERAPY RECOMMENDATIONS

Mild to moderate agitation in pregnancy should be managed conservatively with diphenhydramine. Other options include a benzodiazepine, particularly lorazepam, if alcohol withdrawal is suspected. A second-generation antipsychotic such as olanzapine in a rapidly dissolving form or ziprasidone is another option if a rapid response is required.²⁰Table 1 provides a summary of pharmacotherapy recommendations.

Severe agitation may require a combination of agents. A commonly used, safe regimen—colloquially called the “B52 bomb”—is haloperidol 5 mg, lorazepam 2 mg, and diphenhydramine 25 to 50 mg for prophylaxis of dystonia.²⁰

The patient’s response should be monitored closely, as dosing may require modification as a result of pregnancy-related changes in drug distribution, metabolism, and clearance.²¹

Although no study to our knowledge has assessed risk associated with 1-time exposure to any of these classes of medications in pregnant women, the aforementioned data on long-term exposure provide reassurance that single exposure in emergency departments likely has little or no effect for the developing fetus.

PHYSICAL RESTRAINTS FOR AGITATION IN PREGNANCY

Physical restraints along with emergency medications (ie, chemical restraint) may be indicated when the patient poses a danger to herself or others. In some cases, both types of restraint may be required, whether in the emergency room or an inpatient setting.

However, during the second and third trimesters, physical restraints such as 4-point restraints may predispose the patient to inferior vena cava compression syndrome and compromise placental blood flow.⁴ Therefore, pregnant patients after 20 weeks of gestation should be positioned in the left lateral decubitus position, with the right hip positioned 10 to 12 cm off the bed with pillows or blankets. And when restraints are used in pregnant patients, frequent checking of vital signs and physical assessment is needed to mitigate risks.⁴

A 35-year-old woman is admitted to the hospital with a 5-day history of abdominal distention and jaundice. She reports no history of fever, chills, night sweats, abdominal pain, nausea, vomiting, diarrhea, changes in urine color, change in stool color, weight loss, weight gain, or loss of appetite.

She is petite, with a body mass index of 19.4 kg/m². She has no known history of medical conditions or surgery and is not taking any medications. Her family history is unremarkable, and she denies current or past tobacco, alcohol, or illicit drug use.

RECENT TRAVEL

She says that during a trip to Central America several months ago, she had suffered a seizure and was taken to a local hospital, where laboratory testing revealed elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. She says that the rest of the workup at that time was normal.

About 1 week after that incident, she returned home and saw her primary care physician, who ordered further testing, which showed mild hyperbilirubinemia and mild elevation of AST and ALT levels. Her physician attributed the elevations to atovaquone, which she had been taking for malaria prophylaxis, as repeat testing 2 weeks later showed improvement in AST and ALT levels.

The patient says she returned to her normal state of health until about 5 days ago, when she noticed jaundice and abdominal distention, but without abdominal pain, dark urine, or clay-colored stools. She became concerned and went to her local hospital. Testing there noted mild elevation of AST and ALT, as well as an elevated international normalized ratio (INR) and hyperbilirubinemia. Computed tomography of the abdomen and pelvis showed hepatomegaly with possible fatty liver. Because of these results, the patient was transferred to our institution for further evaluation.

EVALUATION AT OUR INSTITUTION

On examination at our institution, she is afebrile, and vital signs are within normal ranges. She has bilateral scleral icterus and diffuse jaundice, but no other skin finding such as rash or spider angioma. She has no lymphadenopathy. Her abdomen is distended, with tense ascites, and her liver is tender to palpation. The tip of the spleen is not palpable.

The cardiovascular examination reveals no murmurs, rubs, or gallops, but she has jugular venous distention and +2 pitting edema of both lower extremities.

On respiratory examination, there is dullness to percussion, with slight crackles on auscultation at the right lung base. The neurologic examination is normal.

Table 1 shows the results of initial laboratory testing.

1. Which study would provide the most information on the cause of ascites?

• Abdominal ultrasonography
• Abdominal paracentesis with ascitic fluid analysis
• Chest radiography
• Echocardiography
• Urine protein-to-creatinine ratio

Abdominal paracentesis with ascitic fluid analysis is the essential study for any patient with clinically apparent new-onset ascites.^1–3 It is the study that provides the most information on the cause of ascites.

In our patient, abdominal paracentesis yields 1,000 mL of straw-colored ascitic fluid, and analysis shows 86 nucleated cells, 28 of which are polymorphonuclear cells, and 0 red blood cells, with negative Gram stain and culture. The ascitic albumin level is 0.85 g/dL, with an ascitic protein of 1.1 g/dL.

Abdominal ultrasonography shows a diffusely echogenic liver, no focal lesions, moderate ascites, normal portal vein flow, no intrahepatic or extrahepatic biliary duct dilation, normal kidney sizes, no hydronephrosis, and no intra-abdominal mass. Chest radiography is clear with no sign of consolidation, edema, or effusion. Echocardiography shows a normal left ventricular ejection fraction with no valvular disease or pericardial effusion. A random urine protein-creatinine ratio is normal at 0.1 (reference range < 0.2).

2. What is the most likely cause of her ascites based on the workup to this point?

• Cirrhosis
• Heart failure
• Nephrotic syndrome
• Portal vein thrombus
• Abdominal malignancy
• Malaria

An initial approach to ascitic fluid analysis is to calculate the serum-ascites albumin gradient (SAAG). The SAAG is calculated as the serum albumin level minus the ascitic fluid albumin level.^4,5 This is useful in determining the cause of the ascites (Figure 1).^4,5 A gradient of 1.1 g/dL or higher indicates portal hypertension.^4,5

Common causes of portal hypertension include cirrhosis, alcoholic hepatitis, heart failure, vascular occlusion syndromes (eg, Budd-Chiari syndrome, portal vein thrombosis), idiopathic portal fibrosis, and metastatic liver disease.^5,6

If portal hypertension is present based on the SAAG, the next step is to review the ascitic protein level to help distinguish between a hepatic and a cardiac etiology of the ascites. An ascitic protein level less than 2.5 g/dL indicates a primary liver pathology (eg, cirrhosis). An ascitic protein level of 2.5 g/dL or greater typically indicates a cardiac condition (eg, heart failure, pericardial disease) with secondary congestive hepatopathy.^5,6

If the SAAG is less than 1.1 g/dL, the ascites is likely not from portal hypertension. Typical causes of a low SAAG include infection, malignancy, pancreatic ascites, and nephrotic syndrome.^5,6

In our patient, the SAAG is 1.35 g/dL (2.2 g/dL minus 0.85 g/dL), ie, elevated and due to portal hypertension. With an SAAG of 1.1 g/dL or greater and an ascitic fluid protein level less than 2.5 g/dL, as in our patient, the most likely cause is cirrhosis.

Heart failure is unlikely based on her normal brain natriuretic peptide level, an ascitic fluid protein level below 2.5 g/dL, and normal results on echocardiography. Nephrotic syndrome is also very unlikely based on the patient’s normal random urine protein-creatinine ratio. Portal vein thrombus and abdominal malignancy are essentially ruled out by the negative results of Doppler abdominal ultrasonography, with normal venous flow and no intra-abdominal mass and coupled with an elevated SAAG.

Although the patient has a history of travel, the incubation period for malaria would not fit the time frame of presentation. Also, she did not have typical malarial symptoms, her rapid malaria test was negative, and a peripheral blood smear for blood parasites was negative. It should be noted, however, that Plasmodium malariae infection classically presents with flulike symptoms and can resemble nephrotic syndrome, including peripheral edema, ascites, heavy proteinuria, hypoalbuminemia, and hyperlipidemia.⁷

3. In which patients is antibiotic prophylaxis against spontaneous bacterial peritonitis (SBP) appropriate?

• Any patient with cirrhosis
• Any patient with cirrhosis who is hospitalized
• Any patient with cirrhosis and an ascitic fluid protein level below 2.0 g/dL
• Any patient with cirrhosis and a history of SBP

Any patient with cirrhosis and a history of SBP should receive prophylactic antibiotics,⁸ as should any patient deemed at high risk of SBP. It is indicated in the following patients:

• Patients with cirrhosis and gastrointestinal bleeding^9,10
• Patients with cirrhosis and a previous episode of SBP⁸
• Patients with cirrhosis and an ascitic fluid protein level less than 1.5 g/dL with either impaired renal function (creatinine ≥ 1.2 mg/dL, blood urea nitrogen level ≥ 25 mg/dL, or serum sodium ≤ 130 mmol/L) or liver failure (Child-Pugh score ≥ 9 and a bilirubin ≥ 3 mg/dL)⁹
• Patients with cirrhosis who are hospitalized for other reasons and have an ascitic protein level < 1.0 g/dL.⁹

Our patient has no signs or symptoms of gastrointestinal bleeding and no history of SBP. Her ascitic fluid protein level is 1.1 g/dL, and she has normal renal function. However, her Child-Pugh score is 12 (3 points for total bilirubin > 3 mg/dL, 3 points for serum albumin < 2.8 g/dL, 2 points for an INR 1.7 to 2.2, 3 points for moderate ascites, and 1 point for no encephalopathy), with a bilirubin of 17.0 mg/dL. Based on this, she is placed on antibiotic prophylaxis for SBP.

Our patient then undergoes an extensive workup for liver disease. Results of tests for toxins, autoimmune diseases, and inheritable diseases are all within normal limits. At this point, despite the patient’s reported negative alcohol history, our leading diagnosis is alcoholic hepatitis.

To confirm this diagnosis, she subsequently undergoes transjugular liver biopsy, considered the gold standard for the diagnosis of alcoholic hepatitis. During the procedure, the hepatic venous pressure gradient is measured at 18 mm Hg (reference range 1–5 mm Hg), suggestive of portal hypertension. The pathology study shows severe fatty change, active steatohepatitis with ballooning degeneration, easily identifiable Mallory-Denk bodies, and prominent neutrophilic infiltration, as well as extensive bridging fibrosis (Figure 2). These findings point to alcoholic hepatitis.

After the biopsy results, we speak with the patient further about her alcohol habits. At this point, she informs us that she has consumed significant amounts of alcohol since the age of 18 (6 to 12 alcoholic beverages per day, including beer and hard liquor). Therefore, based on this new information, on her jaundice and ascites, and on results of laboratory testing and biopsy, we confirmed our diagnosis of alcoholic hepatitis.

4. When is drug treatment appropriate for alcoholic hepatitis?

• Model for End-stage Liver Disease (MELD) score greater than 12
• MELD score greater than 15
• Maddrey Discriminant Function score greater than 25
• Maddrey Discriminant Function score greater than 32
• Glasgow score greater than 5
• Glasgow score greater than 7

The best answer is a Maddrey Discriminant Function score greater than 32. A variety of scoring systems have been used to assess the severity of alcoholic hepatitis and to guide treatment, including the Maddrey Discriminant Function score, the MELD score, and the Glasgow score.^11–16 They share similar laboratory values in their calculations, including prothrombin time (or INR) and total bilirubin.^11–16 Typically, a Maddrey Discriminant Function score greater than 32, a Glasgow score of greater than 9, or a MELD score greater than 21 is used to determine whether pharmacologic treatment is indicated.^11–16

The typical treatment is prednisolone or pentoxifylline.^11,17–21 The Lille score is designed to help decide whether to stop corticosteroids after 1 week of administration due to lack of treatment response.²² It predicts mortality rates within 6 months; a score of 0.45 or less indicates a good prognosis, and corticosteroid therapy should continue for 28 days (Figure 3).²²

Our patient’s discriminant function score is 50, her Glasgow score is 10, and her MELD score is 28; thus, she begins treatment with oral prednisolone. Her Lille score at 1 week is 0.119, indicating a good prognosis, and her corticosteroids are continued for a total of 28 days.

It should be highlighted that the most important treatment is abstinence from alcohol.¹¹ Recent literature suggests that any benefit of prednisolone or pentoxifylline in terms of mortality rates is questionable,^19–20 and there is evidence that giving both drugs simultaneously may improve mortality rates,^11,21 but the evidence remains conflicting at this time.

ALCOHOLIC HEPATITIS

Alcoholic hepatitis is a clinical syndrome of jaundice and liver failure, often in the setting of heavy alcohol use for decades.^11,12 The incidence is unknown, but the typical age of presentation is between 40 and 50.^11,12 The chief sign is a rapid onset of jaundice (< 3 months); common signs and symptoms include fever, ascites, proximal muscle loss, and an enlarged, tender liver.¹² Encephalopathy may be seen in severe alcoholic hepatitis.¹²

Our patient is 35 years old. She has jaundice with rapid onset, as well as ascites and a tender liver.

The diagnosis of alcoholic hepatitis must take into account the patient’s history, physical examination, and laboratory findings. Until proven otherwise, the diagnosis should be presumed in the following scenario: ascites and jaundice on examination (usually with a duration < 3 months); a history of heavy alcohol use; neutrophilic leukocytosis; an AST level that is elevated but below 300 U/L; an ALT level above the normal range but below 300 U/L; an AST-ALT ratio greater than 2; a total serum bilirubin level above 5 mg/dL; and an elevated INR.^11,12 Liver biopsy is the gold standard for diagnosis. Though not routinely done because of risks associated with the procedure, it may help confirm the diagnosis if it is in question.

CASE CONCLUDED

We start our patient on oral prednisolone 40 mg daily for alcoholic hepatitis. Her symptoms and laboratory testing results including bilirubin improve. Her Lille score at 7 days indicates a good prognosis, prompting continuation of corticosteroid treatment for the full 28 days.

She is referred to an outpatient alcohol rehabilitation program and has remained sober as of the last outpatient note.

Alcoholic hepatitis is extremely difficult to diagnose, and no single blood test or imaging study confirms the diagnosis. The history, physical examination findings, and laboratory findings are crucial. If the diagnosis is still in doubt, liver biopsy may help confirm the diagnosis.

A 35-year-old woman is admitted to the hospital with a 5-day history of abdominal distention and jaundice. She reports no history of fever, chills, night sweats, abdominal pain, nausea, vomiting, diarrhea, changes in urine color, change in stool color, weight loss, weight gain, or loss of appetite.

She is petite, with a body mass index of 19.4 kg/m². She has no known history of medical conditions or surgery and is not taking any medications. Her family history is unremarkable, and she denies current or past tobacco, alcohol, or illicit drug use.

RECENT TRAVEL

She says that during a trip to Central America several months ago, she had suffered a seizure and was taken to a local hospital, where laboratory testing revealed elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. She says that the rest of the workup at that time was normal.

About 1 week after that incident, she returned home and saw her primary care physician, who ordered further testing, which showed mild hyperbilirubinemia and mild elevation of AST and ALT levels. Her physician attributed the elevations to atovaquone, which she had been taking for malaria prophylaxis, as repeat testing 2 weeks later showed improvement in AST and ALT levels.

The patient says she returned to her normal state of health until about 5 days ago, when she noticed jaundice and abdominal distention, but without abdominal pain, dark urine, or clay-colored stools. She became concerned and went to her local hospital. Testing there noted mild elevation of AST and ALT, as well as an elevated international normalized ratio (INR) and hyperbilirubinemia. Computed tomography of the abdomen and pelvis showed hepatomegaly with possible fatty liver. Because of these results, the patient was transferred to our institution for further evaluation.

EVALUATION AT OUR INSTITUTION

On examination at our institution, she is afebrile, and vital signs are within normal ranges. She has bilateral scleral icterus and diffuse jaundice, but no other skin finding such as rash or spider angioma. She has no lymphadenopathy. Her abdomen is distended, with tense ascites, and her liver is tender to palpation. The tip of the spleen is not palpable.

The cardiovascular examination reveals no murmurs, rubs, or gallops, but she has jugular venous distention and +2 pitting edema of both lower extremities.

On respiratory examination, there is dullness to percussion, with slight crackles on auscultation at the right lung base. The neurologic examination is normal.

Table 1 shows the results of initial laboratory testing.

1. Which study would provide the most information on the cause of ascites?

• Abdominal ultrasonography
• Abdominal paracentesis with ascitic fluid analysis
• Chest radiography
• Echocardiography
• Urine protein-to-creatinine ratio

Abdominal paracentesis with ascitic fluid analysis is the essential study for any patient with clinically apparent new-onset ascites.^1–3 It is the study that provides the most information on the cause of ascites.

In our patient, abdominal paracentesis yields 1,000 mL of straw-colored ascitic fluid, and analysis shows 86 nucleated cells, 28 of which are polymorphonuclear cells, and 0 red blood cells, with negative Gram stain and culture. The ascitic albumin level is 0.85 g/dL, with an ascitic protein of 1.1 g/dL.

Abdominal ultrasonography shows a diffusely echogenic liver, no focal lesions, moderate ascites, normal portal vein flow, no intrahepatic or extrahepatic biliary duct dilation, normal kidney sizes, no hydronephrosis, and no intra-abdominal mass. Chest radiography is clear with no sign of consolidation, edema, or effusion. Echocardiography shows a normal left ventricular ejection fraction with no valvular disease or pericardial effusion. A random urine protein-creatinine ratio is normal at 0.1 (reference range < 0.2).

2. What is the most likely cause of her ascites based on the workup to this point?

• Cirrhosis
• Heart failure
• Nephrotic syndrome
• Portal vein thrombus
• Abdominal malignancy
• Malaria

An initial approach to ascitic fluid analysis is to calculate the serum-ascites albumin gradient (SAAG). The SAAG is calculated as the serum albumin level minus the ascitic fluid albumin level.^4,5 This is useful in determining the cause of the ascites (Figure 1).^4,5 A gradient of 1.1 g/dL or higher indicates portal hypertension.^4,5

Common causes of portal hypertension include cirrhosis, alcoholic hepatitis, heart failure, vascular occlusion syndromes (eg, Budd-Chiari syndrome, portal vein thrombosis), idiopathic portal fibrosis, and metastatic liver disease.^5,6

If portal hypertension is present based on the SAAG, the next step is to review the ascitic protein level to help distinguish between a hepatic and a cardiac etiology of the ascites. An ascitic protein level less than 2.5 g/dL indicates a primary liver pathology (eg, cirrhosis). An ascitic protein level of 2.5 g/dL or greater typically indicates a cardiac condition (eg, heart failure, pericardial disease) with secondary congestive hepatopathy.^5,6

If the SAAG is less than 1.1 g/dL, the ascites is likely not from portal hypertension. Typical causes of a low SAAG include infection, malignancy, pancreatic ascites, and nephrotic syndrome.^5,6

In our patient, the SAAG is 1.35 g/dL (2.2 g/dL minus 0.85 g/dL), ie, elevated and due to portal hypertension. With an SAAG of 1.1 g/dL or greater and an ascitic fluid protein level less than 2.5 g/dL, as in our patient, the most likely cause is cirrhosis.

Heart failure is unlikely based on her normal brain natriuretic peptide level, an ascitic fluid protein level below 2.5 g/dL, and normal results on echocardiography. Nephrotic syndrome is also very unlikely based on the patient’s normal random urine protein-creatinine ratio. Portal vein thrombus and abdominal malignancy are essentially ruled out by the negative results of Doppler abdominal ultrasonography, with normal venous flow and no intra-abdominal mass and coupled with an elevated SAAG.

Although the patient has a history of travel, the incubation period for malaria would not fit the time frame of presentation. Also, she did not have typical malarial symptoms, her rapid malaria test was negative, and a peripheral blood smear for blood parasites was negative. It should be noted, however, that Plasmodium malariae infection classically presents with flulike symptoms and can resemble nephrotic syndrome, including peripheral edema, ascites, heavy proteinuria, hypoalbuminemia, and hyperlipidemia.⁷

3. In which patients is antibiotic prophylaxis against spontaneous bacterial peritonitis (SBP) appropriate?

• Any patient with cirrhosis
• Any patient with cirrhosis who is hospitalized
• Any patient with cirrhosis and an ascitic fluid protein level below 2.0 g/dL
• Any patient with cirrhosis and a history of SBP

Any patient with cirrhosis and a history of SBP should receive prophylactic antibiotics,⁸ as should any patient deemed at high risk of SBP. It is indicated in the following patients:

• Patients with cirrhosis and gastrointestinal bleeding^9,10
• Patients with cirrhosis and a previous episode of SBP⁸
• Patients with cirrhosis and an ascitic fluid protein level less than 1.5 g/dL with either impaired renal function (creatinine ≥ 1.2 mg/dL, blood urea nitrogen level ≥ 25 mg/dL, or serum sodium ≤ 130 mmol/L) or liver failure (Child-Pugh score ≥ 9 and a bilirubin ≥ 3 mg/dL)⁹
• Patients with cirrhosis who are hospitalized for other reasons and have an ascitic protein level < 1.0 g/dL.⁹

Our patient has no signs or symptoms of gastrointestinal bleeding and no history of SBP. Her ascitic fluid protein level is 1.1 g/dL, and she has normal renal function. However, her Child-Pugh score is 12 (3 points for total bilirubin > 3 mg/dL, 3 points for serum albumin < 2.8 g/dL, 2 points for an INR 1.7 to 2.2, 3 points for moderate ascites, and 1 point for no encephalopathy), with a bilirubin of 17.0 mg/dL. Based on this, she is placed on antibiotic prophylaxis for SBP.

Our patient then undergoes an extensive workup for liver disease. Results of tests for toxins, autoimmune diseases, and inheritable diseases are all within normal limits. At this point, despite the patient’s reported negative alcohol history, our leading diagnosis is alcoholic hepatitis.

To confirm this diagnosis, she subsequently undergoes transjugular liver biopsy, considered the gold standard for the diagnosis of alcoholic hepatitis. During the procedure, the hepatic venous pressure gradient is measured at 18 mm Hg (reference range 1–5 mm Hg), suggestive of portal hypertension. The pathology study shows severe fatty change, active steatohepatitis with ballooning degeneration, easily identifiable Mallory-Denk bodies, and prominent neutrophilic infiltration, as well as extensive bridging fibrosis (Figure 2). These findings point to alcoholic hepatitis.

After the biopsy results, we speak with the patient further about her alcohol habits. At this point, she informs us that she has consumed significant amounts of alcohol since the age of 18 (6 to 12 alcoholic beverages per day, including beer and hard liquor). Therefore, based on this new information, on her jaundice and ascites, and on results of laboratory testing and biopsy, we confirmed our diagnosis of alcoholic hepatitis.

4. When is drug treatment appropriate for alcoholic hepatitis?

• Model for End-stage Liver Disease (MELD) score greater than 12
• MELD score greater than 15
• Maddrey Discriminant Function score greater than 25
• Maddrey Discriminant Function score greater than 32
• Glasgow score greater than 5
• Glasgow score greater than 7

The best answer is a Maddrey Discriminant Function score greater than 32. A variety of scoring systems have been used to assess the severity of alcoholic hepatitis and to guide treatment, including the Maddrey Discriminant Function score, the MELD score, and the Glasgow score.^11–16 They share similar laboratory values in their calculations, including prothrombin time (or INR) and total bilirubin.^11–16 Typically, a Maddrey Discriminant Function score greater than 32, a Glasgow score of greater than 9, or a MELD score greater than 21 is used to determine whether pharmacologic treatment is indicated.^11–16

The typical treatment is prednisolone or pentoxifylline.^11,17–21 The Lille score is designed to help decide whether to stop corticosteroids after 1 week of administration due to lack of treatment response.²² It predicts mortality rates within 6 months; a score of 0.45 or less indicates a good prognosis, and corticosteroid therapy should continue for 28 days (Figure 3).²²

Our patient’s discriminant function score is 50, her Glasgow score is 10, and her MELD score is 28; thus, she begins treatment with oral prednisolone. Her Lille score at 1 week is 0.119, indicating a good prognosis, and her corticosteroids are continued for a total of 28 days.

It should be highlighted that the most important treatment is abstinence from alcohol.¹¹ Recent literature suggests that any benefit of prednisolone or pentoxifylline in terms of mortality rates is questionable,^19–20 and there is evidence that giving both drugs simultaneously may improve mortality rates,^11,21 but the evidence remains conflicting at this time.

ALCOHOLIC HEPATITIS

Alcoholic hepatitis is a clinical syndrome of jaundice and liver failure, often in the setting of heavy alcohol use for decades.^11,12 The incidence is unknown, but the typical age of presentation is between 40 and 50.^11,12 The chief sign is a rapid onset of jaundice (< 3 months); common signs and symptoms include fever, ascites, proximal muscle loss, and an enlarged, tender liver.¹² Encephalopathy may be seen in severe alcoholic hepatitis.¹²

Our patient is 35 years old. She has jaundice with rapid onset, as well as ascites and a tender liver.

The diagnosis of alcoholic hepatitis must take into account the patient’s history, physical examination, and laboratory findings. Until proven otherwise, the diagnosis should be presumed in the following scenario: ascites and jaundice on examination (usually with a duration < 3 months); a history of heavy alcohol use; neutrophilic leukocytosis; an AST level that is elevated but below 300 U/L; an ALT level above the normal range but below 300 U/L; an AST-ALT ratio greater than 2; a total serum bilirubin level above 5 mg/dL; and an elevated INR.^11,12 Liver biopsy is the gold standard for diagnosis. Though not routinely done because of risks associated with the procedure, it may help confirm the diagnosis if it is in question.

CASE CONCLUDED

We start our patient on oral prednisolone 40 mg daily for alcoholic hepatitis. Her symptoms and laboratory testing results including bilirubin improve. Her Lille score at 7 days indicates a good prognosis, prompting continuation of corticosteroid treatment for the full 28 days.

She is referred to an outpatient alcohol rehabilitation program and has remained sober as of the last outpatient note.

Alcoholic hepatitis is extremely difficult to diagnose, and no single blood test or imaging study confirms the diagnosis. The history, physical examination findings, and laboratory findings are crucial. If the diagnosis is still in doubt, liver biopsy may help confirm the diagnosis.

A 35-year-old woman is admitted to the hospital with a 5-day history of abdominal distention and jaundice. She reports no history of fever, chills, night sweats, abdominal pain, nausea, vomiting, diarrhea, changes in urine color, change in stool color, weight loss, weight gain, or loss of appetite.

She is petite, with a body mass index of 19.4 kg/m². She has no known history of medical conditions or surgery and is not taking any medications. Her family history is unremarkable, and she denies current or past tobacco, alcohol, or illicit drug use.

RECENT TRAVEL

She says that during a trip to Central America several months ago, she had suffered a seizure and was taken to a local hospital, where laboratory testing revealed elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. She says that the rest of the workup at that time was normal.

About 1 week after that incident, she returned home and saw her primary care physician, who ordered further testing, which showed mild hyperbilirubinemia and mild elevation of AST and ALT levels. Her physician attributed the elevations to atovaquone, which she had been taking for malaria prophylaxis, as repeat testing 2 weeks later showed improvement in AST and ALT levels.

The patient says she returned to her normal state of health until about 5 days ago, when she noticed jaundice and abdominal distention, but without abdominal pain, dark urine, or clay-colored stools. She became concerned and went to her local hospital. Testing there noted mild elevation of AST and ALT, as well as an elevated international normalized ratio (INR) and hyperbilirubinemia. Computed tomography of the abdomen and pelvis showed hepatomegaly with possible fatty liver. Because of these results, the patient was transferred to our institution for further evaluation.

EVALUATION AT OUR INSTITUTION

On examination at our institution, she is afebrile, and vital signs are within normal ranges. She has bilateral scleral icterus and diffuse jaundice, but no other skin finding such as rash or spider angioma. She has no lymphadenopathy. Her abdomen is distended, with tense ascites, and her liver is tender to palpation. The tip of the spleen is not palpable.

The cardiovascular examination reveals no murmurs, rubs, or gallops, but she has jugular venous distention and +2 pitting edema of both lower extremities.

On respiratory examination, there is dullness to percussion, with slight crackles on auscultation at the right lung base. The neurologic examination is normal.

Table 1 shows the results of initial laboratory testing.

1. Which study would provide the most information on the cause of ascites?

• Abdominal ultrasonography
• Abdominal paracentesis with ascitic fluid analysis
• Chest radiography
• Echocardiography
• Urine protein-to-creatinine ratio

Abdominal paracentesis with ascitic fluid analysis is the essential study for any patient with clinically apparent new-onset ascites.^1–3 It is the study that provides the most information on the cause of ascites.

In our patient, abdominal paracentesis yields 1,000 mL of straw-colored ascitic fluid, and analysis shows 86 nucleated cells, 28 of which are polymorphonuclear cells, and 0 red blood cells, with negative Gram stain and culture. The ascitic albumin level is 0.85 g/dL, with an ascitic protein of 1.1 g/dL.

Abdominal ultrasonography shows a diffusely echogenic liver, no focal lesions, moderate ascites, normal portal vein flow, no intrahepatic or extrahepatic biliary duct dilation, normal kidney sizes, no hydronephrosis, and no intra-abdominal mass. Chest radiography is clear with no sign of consolidation, edema, or effusion. Echocardiography shows a normal left ventricular ejection fraction with no valvular disease or pericardial effusion. A random urine protein-creatinine ratio is normal at 0.1 (reference range < 0.2).

2. What is the most likely cause of her ascites based on the workup to this point?

• Cirrhosis
• Heart failure
• Nephrotic syndrome
• Portal vein thrombus
• Abdominal malignancy
• Malaria

An initial approach to ascitic fluid analysis is to calculate the serum-ascites albumin gradient (SAAG). The SAAG is calculated as the serum albumin level minus the ascitic fluid albumin level.^4,5 This is useful in determining the cause of the ascites (Figure 1).^4,5 A gradient of 1.1 g/dL or higher indicates portal hypertension.^4,5

Common causes of portal hypertension include cirrhosis, alcoholic hepatitis, heart failure, vascular occlusion syndromes (eg, Budd-Chiari syndrome, portal vein thrombosis), idiopathic portal fibrosis, and metastatic liver disease.^5,6

If portal hypertension is present based on the SAAG, the next step is to review the ascitic protein level to help distinguish between a hepatic and a cardiac etiology of the ascites. An ascitic protein level less than 2.5 g/dL indicates a primary liver pathology (eg, cirrhosis). An ascitic protein level of 2.5 g/dL or greater typically indicates a cardiac condition (eg, heart failure, pericardial disease) with secondary congestive hepatopathy.^5,6

If the SAAG is less than 1.1 g/dL, the ascites is likely not from portal hypertension. Typical causes of a low SAAG include infection, malignancy, pancreatic ascites, and nephrotic syndrome.^5,6

In our patient, the SAAG is 1.35 g/dL (2.2 g/dL minus 0.85 g/dL), ie, elevated and due to portal hypertension. With an SAAG of 1.1 g/dL or greater and an ascitic fluid protein level less than 2.5 g/dL, as in our patient, the most likely cause is cirrhosis.

Heart failure is unlikely based on her normal brain natriuretic peptide level, an ascitic fluid protein level below 2.5 g/dL, and normal results on echocardiography. Nephrotic syndrome is also very unlikely based on the patient’s normal random urine protein-creatinine ratio. Portal vein thrombus and abdominal malignancy are essentially ruled out by the negative results of Doppler abdominal ultrasonography, with normal venous flow and no intra-abdominal mass and coupled with an elevated SAAG.

Although the patient has a history of travel, the incubation period for malaria would not fit the time frame of presentation. Also, she did not have typical malarial symptoms, her rapid malaria test was negative, and a peripheral blood smear for blood parasites was negative. It should be noted, however, that Plasmodium malariae infection classically presents with flulike symptoms and can resemble nephrotic syndrome, including peripheral edema, ascites, heavy proteinuria, hypoalbuminemia, and hyperlipidemia.⁷

3. In which patients is antibiotic prophylaxis against spontaneous bacterial peritonitis (SBP) appropriate?

• Any patient with cirrhosis
• Any patient with cirrhosis who is hospitalized
• Any patient with cirrhosis and an ascitic fluid protein level below 2.0 g/dL
• Any patient with cirrhosis and a history of SBP

Any patient with cirrhosis and a history of SBP should receive prophylactic antibiotics,⁸ as should any patient deemed at high risk of SBP. It is indicated in the following patients:

• Patients with cirrhosis and gastrointestinal bleeding^9,10
• Patients with cirrhosis and a previous episode of SBP⁸
• Patients with cirrhosis and an ascitic fluid protein level less than 1.5 g/dL with either impaired renal function (creatinine ≥ 1.2 mg/dL, blood urea nitrogen level ≥ 25 mg/dL, or serum sodium ≤ 130 mmol/L) or liver failure (Child-Pugh score ≥ 9 and a bilirubin ≥ 3 mg/dL)⁹
• Patients with cirrhosis who are hospitalized for other reasons and have an ascitic protein level < 1.0 g/dL.⁹

Our patient has no signs or symptoms of gastrointestinal bleeding and no history of SBP. Her ascitic fluid protein level is 1.1 g/dL, and she has normal renal function. However, her Child-Pugh score is 12 (3 points for total bilirubin > 3 mg/dL, 3 points for serum albumin < 2.8 g/dL, 2 points for an INR 1.7 to 2.2, 3 points for moderate ascites, and 1 point for no encephalopathy), with a bilirubin of 17.0 mg/dL. Based on this, she is placed on antibiotic prophylaxis for SBP.

Our patient then undergoes an extensive workup for liver disease. Results of tests for toxins, autoimmune diseases, and inheritable diseases are all within normal limits. At this point, despite the patient’s reported negative alcohol history, our leading diagnosis is alcoholic hepatitis.

To confirm this diagnosis, she subsequently undergoes transjugular liver biopsy, considered the gold standard for the diagnosis of alcoholic hepatitis. During the procedure, the hepatic venous pressure gradient is measured at 18 mm Hg (reference range 1–5 mm Hg), suggestive of portal hypertension. The pathology study shows severe fatty change, active steatohepatitis with ballooning degeneration, easily identifiable Mallory-Denk bodies, and prominent neutrophilic infiltration, as well as extensive bridging fibrosis (Figure 2). These findings point to alcoholic hepatitis.

After the biopsy results, we speak with the patient further about her alcohol habits. At this point, she informs us that she has consumed significant amounts of alcohol since the age of 18 (6 to 12 alcoholic beverages per day, including beer and hard liquor). Therefore, based on this new information, on her jaundice and ascites, and on results of laboratory testing and biopsy, we confirmed our diagnosis of alcoholic hepatitis.

4. When is drug treatment appropriate for alcoholic hepatitis?

• Model for End-stage Liver Disease (MELD) score greater than 12
• MELD score greater than 15
• Maddrey Discriminant Function score greater than 25
• Maddrey Discriminant Function score greater than 32
• Glasgow score greater than 5
• Glasgow score greater than 7

The best answer is a Maddrey Discriminant Function score greater than 32. A variety of scoring systems have been used to assess the severity of alcoholic hepatitis and to guide treatment, including the Maddrey Discriminant Function score, the MELD score, and the Glasgow score.^11–16 They share similar laboratory values in their calculations, including prothrombin time (or INR) and total bilirubin.^11–16 Typically, a Maddrey Discriminant Function score greater than 32, a Glasgow score of greater than 9, or a MELD score greater than 21 is used to determine whether pharmacologic treatment is indicated.^11–16

The typical treatment is prednisolone or pentoxifylline.^11,17–21 The Lille score is designed to help decide whether to stop corticosteroids after 1 week of administration due to lack of treatment response.²² It predicts mortality rates within 6 months; a score of 0.45 or less indicates a good prognosis, and corticosteroid therapy should continue for 28 days (Figure 3).²²

Our patient’s discriminant function score is 50, her Glasgow score is 10, and her MELD score is 28; thus, she begins treatment with oral prednisolone. Her Lille score at 1 week is 0.119, indicating a good prognosis, and her corticosteroids are continued for a total of 28 days.

It should be highlighted that the most important treatment is abstinence from alcohol.¹¹ Recent literature suggests that any benefit of prednisolone or pentoxifylline in terms of mortality rates is questionable,^19–20 and there is evidence that giving both drugs simultaneously may improve mortality rates,^11,21 but the evidence remains conflicting at this time.

ALCOHOLIC HEPATITIS

Alcoholic hepatitis is a clinical syndrome of jaundice and liver failure, often in the setting of heavy alcohol use for decades.^11,12 The incidence is unknown, but the typical age of presentation is between 40 and 50.^11,12 The chief sign is a rapid onset of jaundice (< 3 months); common signs and symptoms include fever, ascites, proximal muscle loss, and an enlarged, tender liver.¹² Encephalopathy may be seen in severe alcoholic hepatitis.¹²

Our patient is 35 years old. She has jaundice with rapid onset, as well as ascites and a tender liver.

The diagnosis of alcoholic hepatitis must take into account the patient’s history, physical examination, and laboratory findings. Until proven otherwise, the diagnosis should be presumed in the following scenario: ascites and jaundice on examination (usually with a duration < 3 months); a history of heavy alcohol use; neutrophilic leukocytosis; an AST level that is elevated but below 300 U/L; an ALT level above the normal range but below 300 U/L; an AST-ALT ratio greater than 2; a total serum bilirubin level above 5 mg/dL; and an elevated INR.^11,12 Liver biopsy is the gold standard for diagnosis. Though not routinely done because of risks associated with the procedure, it may help confirm the diagnosis if it is in question.

CASE CONCLUDED

We start our patient on oral prednisolone 40 mg daily for alcoholic hepatitis. Her symptoms and laboratory testing results including bilirubin improve. Her Lille score at 7 days indicates a good prognosis, prompting continuation of corticosteroid treatment for the full 28 days.

She is referred to an outpatient alcohol rehabilitation program and has remained sober as of the last outpatient note.

Alcoholic hepatitis is extremely difficult to diagnose, and no single blood test or imaging study confirms the diagnosis. The history, physical examination findings, and laboratory findings are crucial. If the diagnosis is still in doubt, liver biopsy may help confirm the diagnosis.

A 40-year-old woman with a history of hypertension, who was recently started on a diuretic, presents to the emergency department after a witnessed syncopal event. She reports a prodrome of lightheadedness, nausea, and darkening of her vision that occurred a few seconds after standing, followed by loss of consciousness. She had a complete, spontaneous recovery after 10 seconds, but upon arousal she noticed she had lost bladder control.

Her blood pressure is 120/80 mm Hg supine, 110/70 mm Hg sitting, and 90/60 mm Hg standing. She has no focal neurologic deficits. The cardiac examination is normal, without murmurs, and electrocardiography shows sinus tachycardia (heart rate 110 bpm) without other abnormalities. Results of laboratory testing are unremarkable.

Should you order neuroimaging to evaluate for syncope?

DEFINITIONS, CLASSIFICATIONS

Syncope is an abrupt loss of consciousness due to transient global cerebral hypoperfusion, with a concomitant loss of postural tone and rapid, spontaneous recovery.¹ Recovery from syncope is characterized by immediate restoration of orientation and normal behavior, although the period after recovery may be accompanied by fatigue.²

The European Society of Cardiology² has classified syncope into 3 main categories: reflex (neurally mediated) syncope, syncope due to orthostatic hypotension, and cardiac syncope. Determining the cause is critical, as this determines the prognosis.

KEYS TO THE EVALUATION

According to the 2017 American College of Cardiology/American Heart Association (ACC/AHA) and the 2009 European Society of Cardiology guidelines, the evaluation of syncope should include a thorough history, taken from the patient and witnesses, and a complete physical examination. This can identify the cause of syncope in up to 50% of cases and differentiate between cardiac and noncardiac causes. Features that point to cardiac syncope include age older than 60, male sex, known heart disease, brief prodrome, syncope during exertion or when supine, first syncopal event, family history of sudden cardiac death, and abnormal physical examination.¹

Features that suggest noncardiac syncope are young age; syncope only when standing; recurrent syncope; a prodrome of nausea, vomiting, and a warm sensation; and triggers such as dehydration, pain, distressful stimulus, cough, laugh micturition, defecation, and swallowing.¹

Electrocardiography should follow the history and physical examination. When done at presentation, electrocardiography is diagnostic in only about 5% of cases. However, given the importance of the diagnosis, it remains an essential part of the initial evaluation of syncope.³

If a clear cause of syncope is identified at this point, no further workup is needed, and the cause of syncope should be addressed.¹ If the cause is still unclear, the ACC/AHA guidelines recommend further evaluation based on the clinical presentation and risk stratification.

Routine use of additional testing is costly; tests should be ordered on the basis of their potential diagnostic and prognostic value. Additional evaluation should follow a stepwise approach and can include targeted blood work, autonomic nerve evaluation, tilt-table testing, transthoracic echocardiography, stress testing, electrocardiographic monitoring, and electrophysiologic testing.¹

Syncope is rarely a manifestation of neurologic disease, yet 11% to 58% of patients with a first episode of uncomplicated syncope undergo extensive neuroimaging with magnetic resonance imaging, computed tomography, electroencephalography (EEG), and carotid ultrasonography.⁴ Evidence suggests that routine neurologic testing is of limited value given its low diagnostic yield and high cost.

Epilepsy is the most common neurologic cause of loss of consciousness but is estimated to account for less than 5% of patients with syncope.⁵ A thorough and thoughtful neurologic history and examination is often enough to distinguish between syncope, convulsive syncope, epileptic convulsions, and pseudosyncope.

In syncope, the loss of consciousness usually occurs 30 seconds to several minutes after standing. It presents with or without a prodrome (warmth, palpitations, and diaphoresis) and can be relieved with supine positioning. True loss of consciousness usually lasts less than a minute and is accompanied by loss of postural tone, with little or no fatigue in the recovery period.⁶

Conversely, in convulsive syncope, the prodrome can include pallor and diaphoresis. Loss of consciousness lasts about 30 seconds but is accompanied by fixed gaze, upward eye deviation, nuchal rigidity, tonic spasms, myoclonic jerks, tonic-clonic convulsions, and oral automatisms.⁶

Pseudosyncope is characterized by a prodrome of lightheadedness, shortness of breath, chest pain, and tingling sensations, followed by episodes of apparent loss of consciousness that last longer than several minutes and occur multiple times a day. During these episodes, patients purposefully try to avoid trauma when they lose consciousness, and almost always keep their eyes closed, in contrast to syncopal episodes, when the eyes are open and glassy.⁷

ROLE OF ELECTROENCEPHALOGRAPHY

If the diagnosis remains unclear after the history and neurologic examination, EEG is recommended (class IIa, ie, reasonable, can be useful) during tilt-table testing, as it can help differentiate syncope, pseudosyncope, and epilepsy.¹

In an epileptic convulsion, EEG shows epileptiform discharges, whereas in syncope, it shows diffuse brainwave slowing with delta waves and a flatline pattern. In pseudosyncope and psychogenic nonepileptic seizures, EEG shows normal activity.⁸

Routine EEG is not recommended if there are no specific neurologic signs of epilepsy or if the history and neurologic examination indicate syncope or pseudosyncope.¹

Structural brain disease does not typically present with transient global cerebral hypoperfusion resulting in syncope, so magnetic resonance imaging and computed tomography have a low diagnostic yield. Studies have revealed that for the 11% to 58% of patients who undergo neuroimaging, it establishes a diagnosis in only 0.2% to 1%.⁹ For this reason and in view of their high cost, these imaging tests should not be routinely ordered in the evaluation of syncope.^4,10 Similarly, carotid artery imaging should not be routinely ordered if there is no focal neurologic finding suggesting unilateral ischemia.¹⁰

CASE CONTINUED

In our 40-year-old patient, the history suggests dehydration, as she recently started taking a diuretic. Thus, laboratory testing is reasonable.

Loss of bladder control is often interpreted as a red flag for neurologic disease, but syncope can often present with urinary incontinence. Urinary incontinence may also occur in epileptic seizure and in nonepileptic events such as syncope. A pooled analysis by Brigo et al¹¹ determined that urinary incontinence had no value in distinguishing between epilepsy and syncope. Therefore, this physical finding should not incline the clinician to one diagnosis or the other.


Given our patient’s presentation, findings on physical examination, and absence of focal neurologic deficits, she should not undergo neuroimaging for syncope evaluation. The more likely cause of her syncope is orthostatic intolerance (orthostatic hypotension or vasovagal syncope) in the setting of intravascular volume depletion, likely secondary to diuretic use. Obtaining orthostatic vital signs is mandatory, and this confirms the diagnosis.

A 40-year-old woman with a history of hypertension, who was recently started on a diuretic, presents to the emergency department after a witnessed syncopal event. She reports a prodrome of lightheadedness, nausea, and darkening of her vision that occurred a few seconds after standing, followed by loss of consciousness. She had a complete, spontaneous recovery after 10 seconds, but upon arousal she noticed she had lost bladder control.

Her blood pressure is 120/80 mm Hg supine, 110/70 mm Hg sitting, and 90/60 mm Hg standing. She has no focal neurologic deficits. The cardiac examination is normal, without murmurs, and electrocardiography shows sinus tachycardia (heart rate 110 bpm) without other abnormalities. Results of laboratory testing are unremarkable.

Should you order neuroimaging to evaluate for syncope?

DEFINITIONS, CLASSIFICATIONS

Syncope is an abrupt loss of consciousness due to transient global cerebral hypoperfusion, with a concomitant loss of postural tone and rapid, spontaneous recovery.¹ Recovery from syncope is characterized by immediate restoration of orientation and normal behavior, although the period after recovery may be accompanied by fatigue.²

The European Society of Cardiology² has classified syncope into 3 main categories: reflex (neurally mediated) syncope, syncope due to orthostatic hypotension, and cardiac syncope. Determining the cause is critical, as this determines the prognosis.

KEYS TO THE EVALUATION

According to the 2017 American College of Cardiology/American Heart Association (ACC/AHA) and the 2009 European Society of Cardiology guidelines, the evaluation of syncope should include a thorough history, taken from the patient and witnesses, and a complete physical examination. This can identify the cause of syncope in up to 50% of cases and differentiate between cardiac and noncardiac causes. Features that point to cardiac syncope include age older than 60, male sex, known heart disease, brief prodrome, syncope during exertion or when supine, first syncopal event, family history of sudden cardiac death, and abnormal physical examination.¹

Features that suggest noncardiac syncope are young age; syncope only when standing; recurrent syncope; a prodrome of nausea, vomiting, and a warm sensation; and triggers such as dehydration, pain, distressful stimulus, cough, laugh micturition, defecation, and swallowing.¹

Electrocardiography should follow the history and physical examination. When done at presentation, electrocardiography is diagnostic in only about 5% of cases. However, given the importance of the diagnosis, it remains an essential part of the initial evaluation of syncope.³

If a clear cause of syncope is identified at this point, no further workup is needed, and the cause of syncope should be addressed.¹ If the cause is still unclear, the ACC/AHA guidelines recommend further evaluation based on the clinical presentation and risk stratification.

Routine use of additional testing is costly; tests should be ordered on the basis of their potential diagnostic and prognostic value. Additional evaluation should follow a stepwise approach and can include targeted blood work, autonomic nerve evaluation, tilt-table testing, transthoracic echocardiography, stress testing, electrocardiographic monitoring, and electrophysiologic testing.¹

Syncope is rarely a manifestation of neurologic disease, yet 11% to 58% of patients with a first episode of uncomplicated syncope undergo extensive neuroimaging with magnetic resonance imaging, computed tomography, electroencephalography (EEG), and carotid ultrasonography.⁴ Evidence suggests that routine neurologic testing is of limited value given its low diagnostic yield and high cost.

Epilepsy is the most common neurologic cause of loss of consciousness but is estimated to account for less than 5% of patients with syncope.⁵ A thorough and thoughtful neurologic history and examination is often enough to distinguish between syncope, convulsive syncope, epileptic convulsions, and pseudosyncope.

In syncope, the loss of consciousness usually occurs 30 seconds to several minutes after standing. It presents with or without a prodrome (warmth, palpitations, and diaphoresis) and can be relieved with supine positioning. True loss of consciousness usually lasts less than a minute and is accompanied by loss of postural tone, with little or no fatigue in the recovery period.⁶

Conversely, in convulsive syncope, the prodrome can include pallor and diaphoresis. Loss of consciousness lasts about 30 seconds but is accompanied by fixed gaze, upward eye deviation, nuchal rigidity, tonic spasms, myoclonic jerks, tonic-clonic convulsions, and oral automatisms.⁶

Pseudosyncope is characterized by a prodrome of lightheadedness, shortness of breath, chest pain, and tingling sensations, followed by episodes of apparent loss of consciousness that last longer than several minutes and occur multiple times a day. During these episodes, patients purposefully try to avoid trauma when they lose consciousness, and almost always keep their eyes closed, in contrast to syncopal episodes, when the eyes are open and glassy.⁷

ROLE OF ELECTROENCEPHALOGRAPHY

If the diagnosis remains unclear after the history and neurologic examination, EEG is recommended (class IIa, ie, reasonable, can be useful) during tilt-table testing, as it can help differentiate syncope, pseudosyncope, and epilepsy.¹

In an epileptic convulsion, EEG shows epileptiform discharges, whereas in syncope, it shows diffuse brainwave slowing with delta waves and a flatline pattern. In pseudosyncope and psychogenic nonepileptic seizures, EEG shows normal activity.⁸

Routine EEG is not recommended if there are no specific neurologic signs of epilepsy or if the history and neurologic examination indicate syncope or pseudosyncope.¹

Structural brain disease does not typically present with transient global cerebral hypoperfusion resulting in syncope, so magnetic resonance imaging and computed tomography have a low diagnostic yield. Studies have revealed that for the 11% to 58% of patients who undergo neuroimaging, it establishes a diagnosis in only 0.2% to 1%.⁹ For this reason and in view of their high cost, these imaging tests should not be routinely ordered in the evaluation of syncope.^4,10 Similarly, carotid artery imaging should not be routinely ordered if there is no focal neurologic finding suggesting unilateral ischemia.¹⁰

CASE CONTINUED

In our 40-year-old patient, the history suggests dehydration, as she recently started taking a diuretic. Thus, laboratory testing is reasonable.

Loss of bladder control is often interpreted as a red flag for neurologic disease, but syncope can often present with urinary incontinence. Urinary incontinence may also occur in epileptic seizure and in nonepileptic events such as syncope. A pooled analysis by Brigo et al¹¹ determined that urinary incontinence had no value in distinguishing between epilepsy and syncope. Therefore, this physical finding should not incline the clinician to one diagnosis or the other.


Given our patient’s presentation, findings on physical examination, and absence of focal neurologic deficits, she should not undergo neuroimaging for syncope evaluation. The more likely cause of her syncope is orthostatic intolerance (orthostatic hypotension or vasovagal syncope) in the setting of intravascular volume depletion, likely secondary to diuretic use. Obtaining orthostatic vital signs is mandatory, and this confirms the diagnosis.

A 40-year-old woman with a history of hypertension, who was recently started on a diuretic, presents to the emergency department after a witnessed syncopal event. She reports a prodrome of lightheadedness, nausea, and darkening of her vision that occurred a few seconds after standing, followed by loss of consciousness. She had a complete, spontaneous recovery after 10 seconds, but upon arousal she noticed she had lost bladder control.

Her blood pressure is 120/80 mm Hg supine, 110/70 mm Hg sitting, and 90/60 mm Hg standing. She has no focal neurologic deficits. The cardiac examination is normal, without murmurs, and electrocardiography shows sinus tachycardia (heart rate 110 bpm) without other abnormalities. Results of laboratory testing are unremarkable.

Should you order neuroimaging to evaluate for syncope?

DEFINITIONS, CLASSIFICATIONS

Syncope is an abrupt loss of consciousness due to transient global cerebral hypoperfusion, with a concomitant loss of postural tone and rapid, spontaneous recovery.¹ Recovery from syncope is characterized by immediate restoration of orientation and normal behavior, although the period after recovery may be accompanied by fatigue.²

The European Society of Cardiology² has classified syncope into 3 main categories: reflex (neurally mediated) syncope, syncope due to orthostatic hypotension, and cardiac syncope. Determining the cause is critical, as this determines the prognosis.

KEYS TO THE EVALUATION

According to the 2017 American College of Cardiology/American Heart Association (ACC/AHA) and the 2009 European Society of Cardiology guidelines, the evaluation of syncope should include a thorough history, taken from the patient and witnesses, and a complete physical examination. This can identify the cause of syncope in up to 50% of cases and differentiate between cardiac and noncardiac causes. Features that point to cardiac syncope include age older than 60, male sex, known heart disease, brief prodrome, syncope during exertion or when supine, first syncopal event, family history of sudden cardiac death, and abnormal physical examination.¹

Features that suggest noncardiac syncope are young age; syncope only when standing; recurrent syncope; a prodrome of nausea, vomiting, and a warm sensation; and triggers such as dehydration, pain, distressful stimulus, cough, laugh micturition, defecation, and swallowing.¹

Electrocardiography should follow the history and physical examination. When done at presentation, electrocardiography is diagnostic in only about 5% of cases. However, given the importance of the diagnosis, it remains an essential part of the initial evaluation of syncope.³

If a clear cause of syncope is identified at this point, no further workup is needed, and the cause of syncope should be addressed.¹ If the cause is still unclear, the ACC/AHA guidelines recommend further evaluation based on the clinical presentation and risk stratification.

Routine use of additional testing is costly; tests should be ordered on the basis of their potential diagnostic and prognostic value. Additional evaluation should follow a stepwise approach and can include targeted blood work, autonomic nerve evaluation, tilt-table testing, transthoracic echocardiography, stress testing, electrocardiographic monitoring, and electrophysiologic testing.¹

Syncope is rarely a manifestation of neurologic disease, yet 11% to 58% of patients with a first episode of uncomplicated syncope undergo extensive neuroimaging with magnetic resonance imaging, computed tomography, electroencephalography (EEG), and carotid ultrasonography.⁴ Evidence suggests that routine neurologic testing is of limited value given its low diagnostic yield and high cost.

Epilepsy is the most common neurologic cause of loss of consciousness but is estimated to account for less than 5% of patients with syncope.⁵ A thorough and thoughtful neurologic history and examination is often enough to distinguish between syncope, convulsive syncope, epileptic convulsions, and pseudosyncope.

In syncope, the loss of consciousness usually occurs 30 seconds to several minutes after standing. It presents with or without a prodrome (warmth, palpitations, and diaphoresis) and can be relieved with supine positioning. True loss of consciousness usually lasts less than a minute and is accompanied by loss of postural tone, with little or no fatigue in the recovery period.⁶

Conversely, in convulsive syncope, the prodrome can include pallor and diaphoresis. Loss of consciousness lasts about 30 seconds but is accompanied by fixed gaze, upward eye deviation, nuchal rigidity, tonic spasms, myoclonic jerks, tonic-clonic convulsions, and oral automatisms.⁶

Pseudosyncope is characterized by a prodrome of lightheadedness, shortness of breath, chest pain, and tingling sensations, followed by episodes of apparent loss of consciousness that last longer than several minutes and occur multiple times a day. During these episodes, patients purposefully try to avoid trauma when they lose consciousness, and almost always keep their eyes closed, in contrast to syncopal episodes, when the eyes are open and glassy.⁷

ROLE OF ELECTROENCEPHALOGRAPHY

If the diagnosis remains unclear after the history and neurologic examination, EEG is recommended (class IIa, ie, reasonable, can be useful) during tilt-table testing, as it can help differentiate syncope, pseudosyncope, and epilepsy.¹

In an epileptic convulsion, EEG shows epileptiform discharges, whereas in syncope, it shows diffuse brainwave slowing with delta waves and a flatline pattern. In pseudosyncope and psychogenic nonepileptic seizures, EEG shows normal activity.⁸

Routine EEG is not recommended if there are no specific neurologic signs of epilepsy or if the history and neurologic examination indicate syncope or pseudosyncope.¹

Structural brain disease does not typically present with transient global cerebral hypoperfusion resulting in syncope, so magnetic resonance imaging and computed tomography have a low diagnostic yield. Studies have revealed that for the 11% to 58% of patients who undergo neuroimaging, it establishes a diagnosis in only 0.2% to 1%.⁹ For this reason and in view of their high cost, these imaging tests should not be routinely ordered in the evaluation of syncope.^4,10 Similarly, carotid artery imaging should not be routinely ordered if there is no focal neurologic finding suggesting unilateral ischemia.¹⁰

CASE CONTINUED

In our 40-year-old patient, the history suggests dehydration, as she recently started taking a diuretic. Thus, laboratory testing is reasonable.

Loss of bladder control is often interpreted as a red flag for neurologic disease, but syncope can often present with urinary incontinence. Urinary incontinence may also occur in epileptic seizure and in nonepileptic events such as syncope. A pooled analysis by Brigo et al¹¹ determined that urinary incontinence had no value in distinguishing between epilepsy and syncope. Therefore, this physical finding should not incline the clinician to one diagnosis or the other.


Given our patient’s presentation, findings on physical examination, and absence of focal neurologic deficits, she should not undergo neuroimaging for syncope evaluation. The more likely cause of her syncope is orthostatic intolerance (orthostatic hypotension or vasovagal syncope) in the setting of intravascular volume depletion, likely secondary to diuretic use. Obtaining orthostatic vital signs is mandatory, and this confirms the diagnosis.

Reports of cancer date back thousands of years to Egyptian texts. Its existence baffled scientists until the 1950s, when Watson, Crick, and Franklin discovered the structure of DNA, laying the groundwork for identifying the genetic pathways leading to cancer. Currently, cancer is a leading global cause of death and the second leading cause of death in the United States.^1,2

In an effort to curtail cancer and its related morbidity and mortality, population-based screening programs have been implemented with tests that identify precancerous lesions and, preferably, early-stage rather than late-stage cancer.

Screening for cancer can lead to early diagnosis and prevent death from cancer, but the topic continues to provoke controversy.

VALUE OF SCREENING QUESTIONED

In a commentary in the March 2019 Cleveland Clinic Journal of Medicine, Kim et al³ argued that cancer screening is not very effective and that we need to find the balance between the potential benefit and harm.

Using data from the US Preventive Services Task Force (USPSTF) and various studies, the authors showed that although screening can prevent some deaths from breast, colon, prostate, and lung cancer, at least 3 times as many people who are screened still die of those diseases. Given that screening does not eliminate all cancer deaths, has not been definitely shown to decrease the all-cause mortality rate, and has the potential to harm through false-positive results, overdiagnosis, and overtreatment, the authors questioned the utility of screening and encouraged us to discuss the benefits and harms with our patients.

In view of the apparently meager benefit, the USPSTF has relaxed its recommendations for screening for breast and prostate cancer in average-risk populations in recent years, a move that has evoked strong reactions from some clinicians. Proponents of screening argue that preventing late-stage cancers can save money, as the direct and indirect costs of morbidity associated with late-stage cancers are substantial, and that patients prefer screening when a test is available. Current models of screening efficacy do not take these factors into account.⁴

Kim et al, in defending the USPSTF’s position, suggested that the motivation for aggressive testing may be a belief that no harm is greater than the benefit of saving a life. They illustrated this through a Swiftian “modest proposal,” ie, universal prophylactic organectomy to prevent cancer. This hypothetical extreme measure would nearly eliminate the risk of cancer in the removed organs and prevent overdiagnosis and overtreatment of malignancies, but at substantial harm and cost.

In response to this proposal, we would like to point out the alternative extreme: stop all cancer screening programs. The pendulum would swing from what was previously considered a benefit—cancer prevention—to a harm, ie, cancer.

Observational studies, systematic reviews, meta-analyses, and modeling studies show that screening for cervical, colorectal, breast, and prostate cancer decreases disease-specific mortality.^5–11

For example, in lung cancer, the National Lung Screening Trial demonstrated reductions in disease-specific and overall mortality in patients at high risk who underwent low-dose screening computed tomography.¹²

In breast cancer, a systematic review demonstrated decreased disease-specific mortality for women ages 50 through 79 who underwent screening mammography.¹³

In cervical cancer, lower rates of cancer-related death and invasive cancer have also been shown with screening.¹⁴

In colorectal cancer, great strides have been made in reducing both the incidence of and mortality from this disease over the past 30 years through fecal occult blood testing. Early detection shifts the 5-year survival rate—14% for late-stage cancer—to over 90%.¹⁵ Colorectal cancer screening has also been shown to be cost-effective, with savings in excess of $30,000 per life-year gained from screening.¹⁶

Moreover, recent data from the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) screening trial¹⁷ demonstrated a 2-fold higher overall non-cancer-related mortality rate in participants who did not adhere to screening compared with those who were fully adherent to all sex-specific PLCO screening tests when adjusted for age, sex, and ethnicity. Although a possible explanation is that people who adhere to screening recommendations are also likely to have a healthier lifestyle overall, the association persisted (although it was slightly attenuated) even after adjusting for medical risk and behavioral factors.

ON THIS WE CAN AGREE

Like Kim et al, we also believe an informed discussion of screening should occur with each patient—and challenge Kim et al to design an efficient and practical approach to allow providers to do so in a busy office visit aimed to address and manage other competing diseases.

In addition, medical science needs to improve. Methods to increase the efficacy of screening and decrease risks should be explored; these include improving test and operator performance, reducing nonadherence to screening, investigating novel biomarkers or precursors of cancer and pathways that escape current detection, and devising better risk-stratification tools.

Bodies such as the USPSTF should use models that account for factors not considered previously but important when informing patients of potential benefits and harm. Examples include varying sensitivities and specificities at different rounds of testing and accounting for the variability in risk or efficacy affected by race, ethnicity, sex, and patient preferences.

We practice in the era of evidence-based medicine. Guidelines and recommendations are based on the available evidence. As more studies are published, disease mechanisms are better understood, and the effects of previous recommendations are evaluated, cancer screening programs will be further refined or replaced. The balance between benefit and harm will be further delineated.

Kim et al knocked on the door of personalized medicine, where individual screening will be based on individual risk. Until that door is opened, screening should be personalized through the risk-benefit discussions we have with our patients. Ultimately, the choice to undergo screening is the patient’s.

Reports of cancer date back thousands of years to Egyptian texts. Its existence baffled scientists until the 1950s, when Watson, Crick, and Franklin discovered the structure of DNA, laying the groundwork for identifying the genetic pathways leading to cancer. Currently, cancer is a leading global cause of death and the second leading cause of death in the United States.^1,2

In an effort to curtail cancer and its related morbidity and mortality, population-based screening programs have been implemented with tests that identify precancerous lesions and, preferably, early-stage rather than late-stage cancer.

Screening for cancer can lead to early diagnosis and prevent death from cancer, but the topic continues to provoke controversy.

VALUE OF SCREENING QUESTIONED

In a commentary in the March 2019 Cleveland Clinic Journal of Medicine, Kim et al³ argued that cancer screening is not very effective and that we need to find the balance between the potential benefit and harm.

Using data from the US Preventive Services Task Force (USPSTF) and various studies, the authors showed that although screening can prevent some deaths from breast, colon, prostate, and lung cancer, at least 3 times as many people who are screened still die of those diseases. Given that screening does not eliminate all cancer deaths, has not been definitely shown to decrease the all-cause mortality rate, and has the potential to harm through false-positive results, overdiagnosis, and overtreatment, the authors questioned the utility of screening and encouraged us to discuss the benefits and harms with our patients.

In view of the apparently meager benefit, the USPSTF has relaxed its recommendations for screening for breast and prostate cancer in average-risk populations in recent years, a move that has evoked strong reactions from some clinicians. Proponents of screening argue that preventing late-stage cancers can save money, as the direct and indirect costs of morbidity associated with late-stage cancers are substantial, and that patients prefer screening when a test is available. Current models of screening efficacy do not take these factors into account.⁴

Kim et al, in defending the USPSTF’s position, suggested that the motivation for aggressive testing may be a belief that no harm is greater than the benefit of saving a life. They illustrated this through a Swiftian “modest proposal,” ie, universal prophylactic organectomy to prevent cancer. This hypothetical extreme measure would nearly eliminate the risk of cancer in the removed organs and prevent overdiagnosis and overtreatment of malignancies, but at substantial harm and cost.

In response to this proposal, we would like to point out the alternative extreme: stop all cancer screening programs. The pendulum would swing from what was previously considered a benefit—cancer prevention—to a harm, ie, cancer.

Observational studies, systematic reviews, meta-analyses, and modeling studies show that screening for cervical, colorectal, breast, and prostate cancer decreases disease-specific mortality.^5–11

For example, in lung cancer, the National Lung Screening Trial demonstrated reductions in disease-specific and overall mortality in patients at high risk who underwent low-dose screening computed tomography.¹²

In breast cancer, a systematic review demonstrated decreased disease-specific mortality for women ages 50 through 79 who underwent screening mammography.¹³

In cervical cancer, lower rates of cancer-related death and invasive cancer have also been shown with screening.¹⁴

In colorectal cancer, great strides have been made in reducing both the incidence of and mortality from this disease over the past 30 years through fecal occult blood testing. Early detection shifts the 5-year survival rate—14% for late-stage cancer—to over 90%.¹⁵ Colorectal cancer screening has also been shown to be cost-effective, with savings in excess of $30,000 per life-year gained from screening.¹⁶

Moreover, recent data from the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) screening trial¹⁷ demonstrated a 2-fold higher overall non-cancer-related mortality rate in participants who did not adhere to screening compared with those who were fully adherent to all sex-specific PLCO screening tests when adjusted for age, sex, and ethnicity. Although a possible explanation is that people who adhere to screening recommendations are also likely to have a healthier lifestyle overall, the association persisted (although it was slightly attenuated) even after adjusting for medical risk and behavioral factors.

ON THIS WE CAN AGREE

Like Kim et al, we also believe an informed discussion of screening should occur with each patient—and challenge Kim et al to design an efficient and practical approach to allow providers to do so in a busy office visit aimed to address and manage other competing diseases.

In addition, medical science needs to improve. Methods to increase the efficacy of screening and decrease risks should be explored; these include improving test and operator performance, reducing nonadherence to screening, investigating novel biomarkers or precursors of cancer and pathways that escape current detection, and devising better risk-stratification tools.

Bodies such as the USPSTF should use models that account for factors not considered previously but important when informing patients of potential benefits and harm. Examples include varying sensitivities and specificities at different rounds of testing and accounting for the variability in risk or efficacy affected by race, ethnicity, sex, and patient preferences.

We practice in the era of evidence-based medicine. Guidelines and recommendations are based on the available evidence. As more studies are published, disease mechanisms are better understood, and the effects of previous recommendations are evaluated, cancer screening programs will be further refined or replaced. The balance between benefit and harm will be further delineated.

Kim et al knocked on the door of personalized medicine, where individual screening will be based on individual risk. Until that door is opened, screening should be personalized through the risk-benefit discussions we have with our patients. Ultimately, the choice to undergo screening is the patient’s.

Reports of cancer date back thousands of years to Egyptian texts. Its existence baffled scientists until the 1950s, when Watson, Crick, and Franklin discovered the structure of DNA, laying the groundwork for identifying the genetic pathways leading to cancer. Currently, cancer is a leading global cause of death and the second leading cause of death in the United States.^1,2

In an effort to curtail cancer and its related morbidity and mortality, population-based screening programs have been implemented with tests that identify precancerous lesions and, preferably, early-stage rather than late-stage cancer.

Screening for cancer can lead to early diagnosis and prevent death from cancer, but the topic continues to provoke controversy.

VALUE OF SCREENING QUESTIONED

In a commentary in the March 2019 Cleveland Clinic Journal of Medicine, Kim et al³ argued that cancer screening is not very effective and that we need to find the balance between the potential benefit and harm.

Using data from the US Preventive Services Task Force (USPSTF) and various studies, the authors showed that although screening can prevent some deaths from breast, colon, prostate, and lung cancer, at least 3 times as many people who are screened still die of those diseases. Given that screening does not eliminate all cancer deaths, has not been definitely shown to decrease the all-cause mortality rate, and has the potential to harm through false-positive results, overdiagnosis, and overtreatment, the authors questioned the utility of screening and encouraged us to discuss the benefits and harms with our patients.

In view of the apparently meager benefit, the USPSTF has relaxed its recommendations for screening for breast and prostate cancer in average-risk populations in recent years, a move that has evoked strong reactions from some clinicians. Proponents of screening argue that preventing late-stage cancers can save money, as the direct and indirect costs of morbidity associated with late-stage cancers are substantial, and that patients prefer screening when a test is available. Current models of screening efficacy do not take these factors into account.⁴

Kim et al, in defending the USPSTF’s position, suggested that the motivation for aggressive testing may be a belief that no harm is greater than the benefit of saving a life. They illustrated this through a Swiftian “modest proposal,” ie, universal prophylactic organectomy to prevent cancer. This hypothetical extreme measure would nearly eliminate the risk of cancer in the removed organs and prevent overdiagnosis and overtreatment of malignancies, but at substantial harm and cost.

In response to this proposal, we would like to point out the alternative extreme: stop all cancer screening programs. The pendulum would swing from what was previously considered a benefit—cancer prevention—to a harm, ie, cancer.

Observational studies, systematic reviews, meta-analyses, and modeling studies show that screening for cervical, colorectal, breast, and prostate cancer decreases disease-specific mortality.^5–11

For example, in lung cancer, the National Lung Screening Trial demonstrated reductions in disease-specific and overall mortality in patients at high risk who underwent low-dose screening computed tomography.¹²

In breast cancer, a systematic review demonstrated decreased disease-specific mortality for women ages 50 through 79 who underwent screening mammography.¹³

In cervical cancer, lower rates of cancer-related death and invasive cancer have also been shown with screening.¹⁴

In colorectal cancer, great strides have been made in reducing both the incidence of and mortality from this disease over the past 30 years through fecal occult blood testing. Early detection shifts the 5-year survival rate—14% for late-stage cancer—to over 90%.¹⁵ Colorectal cancer screening has also been shown to be cost-effective, with savings in excess of $30,000 per life-year gained from screening.¹⁶

Moreover, recent data from the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) screening trial¹⁷ demonstrated a 2-fold higher overall non-cancer-related mortality rate in participants who did not adhere to screening compared with those who were fully adherent to all sex-specific PLCO screening tests when adjusted for age, sex, and ethnicity. Although a possible explanation is that people who adhere to screening recommendations are also likely to have a healthier lifestyle overall, the association persisted (although it was slightly attenuated) even after adjusting for medical risk and behavioral factors.

ON THIS WE CAN AGREE

Like Kim et al, we also believe an informed discussion of screening should occur with each patient—and challenge Kim et al to design an efficient and practical approach to allow providers to do so in a busy office visit aimed to address and manage other competing diseases.

In addition, medical science needs to improve. Methods to increase the efficacy of screening and decrease risks should be explored; these include improving test and operator performance, reducing nonadherence to screening, investigating novel biomarkers or precursors of cancer and pathways that escape current detection, and devising better risk-stratification tools.

Bodies such as the USPSTF should use models that account for factors not considered previously but important when informing patients of potential benefits and harm. Examples include varying sensitivities and specificities at different rounds of testing and accounting for the variability in risk or efficacy affected by race, ethnicity, sex, and patient preferences.

We practice in the era of evidence-based medicine. Guidelines and recommendations are based on the available evidence. As more studies are published, disease mechanisms are better understood, and the effects of previous recommendations are evaluated, cancer screening programs will be further refined or replaced. The balance between benefit and harm will be further delineated.

Kim et al knocked on the door of personalized medicine, where individual screening will be based on individual risk. Until that door is opened, screening should be personalized through the risk-benefit discussions we have with our patients. Ultimately, the choice to undergo screening is the patient’s.

“Twin berries on one stem, grievous damage has been done to both in regarding the Humanities and Science in any other light than complemental.”
—Sir William Osler¹

The year 2019 marks the 100th anniversary of Sir William Osler’s last public speech. Still reeling from the death of his only son in World War I, he had been asked to give the presidential inaugural address of the Classical Association at Oxford. It was the first time a physician had received the honor, and Osler took the assignment very seriously. He chose to speak about “The old humanities and the new science,” and to call for a reunification of the two fields. “Humanists have not enough Science” he warned, “and Science sadly lacks the Humanities…this unhappy divorce…should never have taken place.”¹  Later, he said that it was the speech to which he had given the greatest thought and preparation. It was in fact Osler’s personal legacy: 2 months later he turned 70, and 7 months later he was dead.

Revisiting the address today, what can Osler teach the high-tech physician of today, when doctors have become “providers” and patients “consumers”? Is Osler’s message still relevant to our craft, or has he simply become an icon of professional nostalgia with little value for our times?

THE NEED FOR THE HUMANITIES IN MEDICINE

Medicine has certainly grown both powerful and successful. Yet it is also confronting hurdles that would have been unimaginable in Osler’s time. Physicians are now the professionals with the highest suicide rate,² a burnout rate as high as 70%,^3,4 rampant depression,⁵ dwindling empathy,⁶ a predominantly negative perception by the public,^7,8 and a disturbing propensity to quit.⁹ These, of course, may just be symptoms of an increasingly meaningless environment wherein doctors have become small cogs in a medical-industrial complex they can’t control or even understand. Still, is it possible that something more personal may have been lost in the way we now select and educate physicians? Could this, in turn, make us less resilient?

In this regard, Osler’s last public speech serves as an enduring reminder of the need for the humanities in medicine. Osler not only believed it, but throughout his life never missed a chance to express in words, writings, and deeds that the humanities are indeed “the hormones” of the profession. In 1919 he warned against the risk of separating our humanistic tradition from the sciences, and urged us “to infect [anyone] with the spirit of the Humanities,” since to him that was “the greatest single gift in education.”¹

Unfortunately, the humanities are slippery, not easily quantifiable, hard to define, and seemingly incompatible with an evidence-based approach. Quite understandably, today’s data-obsessed medicine views them with suspicion. But besides reminding us that in medicine not all that counts can be counted, and not all that can be counted counts, the humanities are in fact a fundamental component of the physician’s skill set.

In a multicenter survey of 5 medical schools,¹⁰ there was indeed a correlation between students’ exposure to the humanities and many of the personal qualities whose absence we lament in today’s medicine: empathy, tolerance for ambiguity, emotional intelligence, and prevention of burnout. Most significant was a strong correlation with wisdom, as measured by the 21-item Brief Wisdom Screening Scale.¹¹ That all these traits may correlate with humanities exposure is intuitive, since the humanities not only teach tolerance and compassion, but also capture the collective experience of those who came before us. Hence, they teach us wisdom. Wisdom is not an ACGME competency, but it’s undoubtedly a prerequisite for the art of healing.¹² In fact, wisdom may very well be the fundamental trait that characterizes a well-rounded physician, since it encompasses empathy, resilience, comfort with ambiguity, and the capacity to learn from the past. Not surprisingly, wisdom in the world was Osler’s closing wish in 1919.

The humanities can also nurture the very personal qualities we desire in physicians. For example, observing drama fosters empathy,¹³ as does taking an elective in medical humanities.¹⁴ Drawing enhances the reading of faces,¹⁵ and observing art improves the art of clinical observation.¹⁶ Reading good literature prompts better detection of emotions,¹⁷ and reflective writing improves students’ well-being.¹⁸ Playing a musical instrument reduces burnout.¹⁹ And an undergraduate major in the humanities correlates with greater tolerance for ambiguity,²⁰ a highly desirable trait in physicians, since it means openness to new ideas and the capacity to better cope with difficult situations.²¹

In fact, some of the qualities fostered by the humanities even translate into better patient care. For instance, tolerance for ambiguity correlates with more positive attitudes towards patients who have frustrating complaints,²² with lower use of resources,²³ and with a career choice in direct patient care.²⁴ Hence, it has been suggested that it should be a prerequisite for medical school admission.²⁵ Physicians’ empathy is also beneficial, since it correlates with a lower rate of complications and better outcomes in the care of diabetic patients.²⁶ This should not come as a surprise. As Hippocrates put it 2,500 years ago, “some patients, though conscious that their condition is perilous, recover their health simply through their contentment with the goodness of the physician.”²⁷

Lastly, studying the humanities may provide crucial antibodies against the pain and suffering that are unavoidable staples of the human condition. To paraphrase Osler, the humanities might vaccinate us against the difficulties of our profession. Hippocrates himself had suggested that “it is well to superintend the sick to make them well, to care for the healthy to keep them well, but also to care for one’s self…”²⁷ That is why many institutions now require medical students to take humanities courses.²⁸

Yet this effort may amount to a rearguard action that arrives too late and provides too little. The humanities should probably be taught before medical school.²⁹ After all, if it’s possible to make a scientist out of a humanist (Osler was living proof), the experience of the past decades seems to suggest that it’s considerably harder to make a humanist out of a scientist—hence the need to revisit undergraduate curricula and admission criteria to medical school, so that students can receive an adequate foundation in both arenas. Ironically, students express positive attitudes toward a liberal education and think it would actually help them as physicians.³⁰ Yet they also understand that the selection process remains tilted towards the sciences.^30–32

For Osler, scientific evidence was important but not a substitute for a humanistic approach. As he reminded students, “The practice of medicine is an art based on science,”³³ whose main goals are to prevent disease, relieve suffering, and heal the sick. To do so, one ought to care more “for the individual patient than for the special features of the disease.”³⁴ But he warned them, “It is much harder to acquire the art than the science.”³⁵ In fact, “The practice of medicine is a calling in which your heart will be exercised equally with your head.”³³ Hence the need to “cultivate equally well hearts and heads.”³⁴ Almost foreseeing our infatuation with guidelines, he also warned against turning medicine into assembly-line work. There are “two great types of practitioners—the routinist and the rationalist,” he said in 1900, and “into the clutches of the demon routine the majority of us ultimately come.”³⁶

Like most great people, Osler was a man of lights, shadows, and contradictions, probably not quite the saint we wish to believe. Yet he provides insights that are as valid today as they were for his own times, and possibly even more so. His 1919 speech is a paean to the humanities, but also a potential eulogy. As a Victorian physician, Osler was a blend of the new science and the old humanities. He knew that “the old art cannot possibly be replaced by, but must be absorbed in, the new science.”³⁵ Yet he could also see the upcoming split between the two cultures, and he tried to warn us. He could in fact foresee the end of an entire way of life. As he said in his address, “there must be a very different civilization or there will be no civilization at all.”¹

The crisis we face in medicine today may indeed be a symptom of a much larger cultural shift. As Osler himself put it, “The philosophies of one age have become the absurdities of the next, and the foolishness of yesterday has become the wisdom of tomorrow.”³³ Like Osler, we live in times of transition that require us to act. If in 1910 Flexner gave us science,³⁷ Osler in 1919 reminded us that medicine also needs the humanities. We ought to heed his message and reconcile the two fields. The alternative is a future full of tricorders and burned-out technicians, but sorely lacking in healers.

“Twin berries on one stem, grievous damage has been done to both in regarding the Humanities and Science in any other light than complemental.”
—Sir William Osler¹

The year 2019 marks the 100th anniversary of Sir William Osler’s last public speech. Still reeling from the death of his only son in World War I, he had been asked to give the presidential inaugural address of the Classical Association at Oxford. It was the first time a physician had received the honor, and Osler took the assignment very seriously. He chose to speak about “The old humanities and the new science,” and to call for a reunification of the two fields. “Humanists have not enough Science” he warned, “and Science sadly lacks the Humanities…this unhappy divorce…should never have taken place.”¹  Later, he said that it was the speech to which he had given the greatest thought and preparation. It was in fact Osler’s personal legacy: 2 months later he turned 70, and 7 months later he was dead.

Revisiting the address today, what can Osler teach the high-tech physician of today, when doctors have become “providers” and patients “consumers”? Is Osler’s message still relevant to our craft, or has he simply become an icon of professional nostalgia with little value for our times?

THE NEED FOR THE HUMANITIES IN MEDICINE

Medicine has certainly grown both powerful and successful. Yet it is also confronting hurdles that would have been unimaginable in Osler’s time. Physicians are now the professionals with the highest suicide rate,² a burnout rate as high as 70%,^3,4 rampant depression,⁵ dwindling empathy,⁶ a predominantly negative perception by the public,^7,8 and a disturbing propensity to quit.⁹ These, of course, may just be symptoms of an increasingly meaningless environment wherein doctors have become small cogs in a medical-industrial complex they can’t control or even understand. Still, is it possible that something more personal may have been lost in the way we now select and educate physicians? Could this, in turn, make us less resilient?

In this regard, Osler’s last public speech serves as an enduring reminder of the need for the humanities in medicine. Osler not only believed it, but throughout his life never missed a chance to express in words, writings, and deeds that the humanities are indeed “the hormones” of the profession. In 1919 he warned against the risk of separating our humanistic tradition from the sciences, and urged us “to infect [anyone] with the spirit of the Humanities,” since to him that was “the greatest single gift in education.”¹

Unfortunately, the humanities are slippery, not easily quantifiable, hard to define, and seemingly incompatible with an evidence-based approach. Quite understandably, today’s data-obsessed medicine views them with suspicion. But besides reminding us that in medicine not all that counts can be counted, and not all that can be counted counts, the humanities are in fact a fundamental component of the physician’s skill set.

In a multicenter survey of 5 medical schools,¹⁰ there was indeed a correlation between students’ exposure to the humanities and many of the personal qualities whose absence we lament in today’s medicine: empathy, tolerance for ambiguity, emotional intelligence, and prevention of burnout. Most significant was a strong correlation with wisdom, as measured by the 21-item Brief Wisdom Screening Scale.¹¹ That all these traits may correlate with humanities exposure is intuitive, since the humanities not only teach tolerance and compassion, but also capture the collective experience of those who came before us. Hence, they teach us wisdom. Wisdom is not an ACGME competency, but it’s undoubtedly a prerequisite for the art of healing.¹² In fact, wisdom may very well be the fundamental trait that characterizes a well-rounded physician, since it encompasses empathy, resilience, comfort with ambiguity, and the capacity to learn from the past. Not surprisingly, wisdom in the world was Osler’s closing wish in 1919.

The humanities can also nurture the very personal qualities we desire in physicians. For example, observing drama fosters empathy,¹³ as does taking an elective in medical humanities.¹⁴ Drawing enhances the reading of faces,¹⁵ and observing art improves the art of clinical observation.¹⁶ Reading good literature prompts better detection of emotions,¹⁷ and reflective writing improves students’ well-being.¹⁸ Playing a musical instrument reduces burnout.¹⁹ And an undergraduate major in the humanities correlates with greater tolerance for ambiguity,²⁰ a highly desirable trait in physicians, since it means openness to new ideas and the capacity to better cope with difficult situations.²¹

In fact, some of the qualities fostered by the humanities even translate into better patient care. For instance, tolerance for ambiguity correlates with more positive attitudes towards patients who have frustrating complaints,²² with lower use of resources,²³ and with a career choice in direct patient care.²⁴ Hence, it has been suggested that it should be a prerequisite for medical school admission.²⁵ Physicians’ empathy is also beneficial, since it correlates with a lower rate of complications and better outcomes in the care of diabetic patients.²⁶ This should not come as a surprise. As Hippocrates put it 2,500 years ago, “some patients, though conscious that their condition is perilous, recover their health simply through their contentment with the goodness of the physician.”²⁷

Lastly, studying the humanities may provide crucial antibodies against the pain and suffering that are unavoidable staples of the human condition. To paraphrase Osler, the humanities might vaccinate us against the difficulties of our profession. Hippocrates himself had suggested that “it is well to superintend the sick to make them well, to care for the healthy to keep them well, but also to care for one’s self…”²⁷ That is why many institutions now require medical students to take humanities courses.²⁸

Yet this effort may amount to a rearguard action that arrives too late and provides too little. The humanities should probably be taught before medical school.²⁹ After all, if it’s possible to make a scientist out of a humanist (Osler was living proof), the experience of the past decades seems to suggest that it’s considerably harder to make a humanist out of a scientist—hence the need to revisit undergraduate curricula and admission criteria to medical school, so that students can receive an adequate foundation in both arenas. Ironically, students express positive attitudes toward a liberal education and think it would actually help them as physicians.³⁰ Yet they also understand that the selection process remains tilted towards the sciences.^30–32

For Osler, scientific evidence was important but not a substitute for a humanistic approach. As he reminded students, “The practice of medicine is an art based on science,”³³ whose main goals are to prevent disease, relieve suffering, and heal the sick. To do so, one ought to care more “for the individual patient than for the special features of the disease.”³⁴ But he warned them, “It is much harder to acquire the art than the science.”³⁵ In fact, “The practice of medicine is a calling in which your heart will be exercised equally with your head.”³³ Hence the need to “cultivate equally well hearts and heads.”³⁴ Almost foreseeing our infatuation with guidelines, he also warned against turning medicine into assembly-line work. There are “two great types of practitioners—the routinist and the rationalist,” he said in 1900, and “into the clutches of the demon routine the majority of us ultimately come.”³⁶

Like most great people, Osler was a man of lights, shadows, and contradictions, probably not quite the saint we wish to believe. Yet he provides insights that are as valid today as they were for his own times, and possibly even more so. His 1919 speech is a paean to the humanities, but also a potential eulogy. As a Victorian physician, Osler was a blend of the new science and the old humanities. He knew that “the old art cannot possibly be replaced by, but must be absorbed in, the new science.”³⁵ Yet he could also see the upcoming split between the two cultures, and he tried to warn us. He could in fact foresee the end of an entire way of life. As he said in his address, “there must be a very different civilization or there will be no civilization at all.”¹

The crisis we face in medicine today may indeed be a symptom of a much larger cultural shift. As Osler himself put it, “The philosophies of one age have become the absurdities of the next, and the foolishness of yesterday has become the wisdom of tomorrow.”³³ Like Osler, we live in times of transition that require us to act. If in 1910 Flexner gave us science,³⁷ Osler in 1919 reminded us that medicine also needs the humanities. We ought to heed his message and reconcile the two fields. The alternative is a future full of tricorders and burned-out technicians, but sorely lacking in healers.

“Twin berries on one stem, grievous damage has been done to both in regarding the Humanities and Science in any other light than complemental.”
—Sir William Osler¹

The year 2019 marks the 100th anniversary of Sir William Osler’s last public speech. Still reeling from the death of his only son in World War I, he had been asked to give the presidential inaugural address of the Classical Association at Oxford. It was the first time a physician had received the honor, and Osler took the assignment very seriously. He chose to speak about “The old humanities and the new science,” and to call for a reunification of the two fields. “Humanists have not enough Science” he warned, “and Science sadly lacks the Humanities…this unhappy divorce…should never have taken place.”¹  Later, he said that it was the speech to which he had given the greatest thought and preparation. It was in fact Osler’s personal legacy: 2 months later he turned 70, and 7 months later he was dead.

Revisiting the address today, what can Osler teach the high-tech physician of today, when doctors have become “providers” and patients “consumers”? Is Osler’s message still relevant to our craft, or has he simply become an icon of professional nostalgia with little value for our times?

THE NEED FOR THE HUMANITIES IN MEDICINE

Medicine has certainly grown both powerful and successful. Yet it is also confronting hurdles that would have been unimaginable in Osler’s time. Physicians are now the professionals with the highest suicide rate,² a burnout rate as high as 70%,^3,4 rampant depression,⁵ dwindling empathy,⁶ a predominantly negative perception by the public,^7,8 and a disturbing propensity to quit.⁹ These, of course, may just be symptoms of an increasingly meaningless environment wherein doctors have become small cogs in a medical-industrial complex they can’t control or even understand. Still, is it possible that something more personal may have been lost in the way we now select and educate physicians? Could this, in turn, make us less resilient?

In this regard, Osler’s last public speech serves as an enduring reminder of the need for the humanities in medicine. Osler not only believed it, but throughout his life never missed a chance to express in words, writings, and deeds that the humanities are indeed “the hormones” of the profession. In 1919 he warned against the risk of separating our humanistic tradition from the sciences, and urged us “to infect [anyone] with the spirit of the Humanities,” since to him that was “the greatest single gift in education.”¹

Unfortunately, the humanities are slippery, not easily quantifiable, hard to define, and seemingly incompatible with an evidence-based approach. Quite understandably, today’s data-obsessed medicine views them with suspicion. But besides reminding us that in medicine not all that counts can be counted, and not all that can be counted counts, the humanities are in fact a fundamental component of the physician’s skill set.

In a multicenter survey of 5 medical schools,¹⁰ there was indeed a correlation between students’ exposure to the humanities and many of the personal qualities whose absence we lament in today’s medicine: empathy, tolerance for ambiguity, emotional intelligence, and prevention of burnout. Most significant was a strong correlation with wisdom, as measured by the 21-item Brief Wisdom Screening Scale.¹¹ That all these traits may correlate with humanities exposure is intuitive, since the humanities not only teach tolerance and compassion, but also capture the collective experience of those who came before us. Hence, they teach us wisdom. Wisdom is not an ACGME competency, but it’s undoubtedly a prerequisite for the art of healing.¹² In fact, wisdom may very well be the fundamental trait that characterizes a well-rounded physician, since it encompasses empathy, resilience, comfort with ambiguity, and the capacity to learn from the past. Not surprisingly, wisdom in the world was Osler’s closing wish in 1919.

The humanities can also nurture the very personal qualities we desire in physicians. For example, observing drama fosters empathy,¹³ as does taking an elective in medical humanities.¹⁴ Drawing enhances the reading of faces,¹⁵ and observing art improves the art of clinical observation.¹⁶ Reading good literature prompts better detection of emotions,¹⁷ and reflective writing improves students’ well-being.¹⁸ Playing a musical instrument reduces burnout.¹⁹ And an undergraduate major in the humanities correlates with greater tolerance for ambiguity,²⁰ a highly desirable trait in physicians, since it means openness to new ideas and the capacity to better cope with difficult situations.²¹

In fact, some of the qualities fostered by the humanities even translate into better patient care. For instance, tolerance for ambiguity correlates with more positive attitudes towards patients who have frustrating complaints,²² with lower use of resources,²³ and with a career choice in direct patient care.²⁴ Hence, it has been suggested that it should be a prerequisite for medical school admission.²⁵ Physicians’ empathy is also beneficial, since it correlates with a lower rate of complications and better outcomes in the care of diabetic patients.²⁶ This should not come as a surprise. As Hippocrates put it 2,500 years ago, “some patients, though conscious that their condition is perilous, recover their health simply through their contentment with the goodness of the physician.”²⁷

Lastly, studying the humanities may provide crucial antibodies against the pain and suffering that are unavoidable staples of the human condition. To paraphrase Osler, the humanities might vaccinate us against the difficulties of our profession. Hippocrates himself had suggested that “it is well to superintend the sick to make them well, to care for the healthy to keep them well, but also to care for one’s self…”²⁷ That is why many institutions now require medical students to take humanities courses.²⁸

Yet this effort may amount to a rearguard action that arrives too late and provides too little. The humanities should probably be taught before medical school.²⁹ After all, if it’s possible to make a scientist out of a humanist (Osler was living proof), the experience of the past decades seems to suggest that it’s considerably harder to make a humanist out of a scientist—hence the need to revisit undergraduate curricula and admission criteria to medical school, so that students can receive an adequate foundation in both arenas. Ironically, students express positive attitudes toward a liberal education and think it would actually help them as physicians.³⁰ Yet they also understand that the selection process remains tilted towards the sciences.^30–32

For Osler, scientific evidence was important but not a substitute for a humanistic approach. As he reminded students, “The practice of medicine is an art based on science,”³³ whose main goals are to prevent disease, relieve suffering, and heal the sick. To do so, one ought to care more “for the individual patient than for the special features of the disease.”³⁴ But he warned them, “It is much harder to acquire the art than the science.”³⁵ In fact, “The practice of medicine is a calling in which your heart will be exercised equally with your head.”³³ Hence the need to “cultivate equally well hearts and heads.”³⁴ Almost foreseeing our infatuation with guidelines, he also warned against turning medicine into assembly-line work. There are “two great types of practitioners—the routinist and the rationalist,” he said in 1900, and “into the clutches of the demon routine the majority of us ultimately come.”³⁶

Like most great people, Osler was a man of lights, shadows, and contradictions, probably not quite the saint we wish to believe. Yet he provides insights that are as valid today as they were for his own times, and possibly even more so. His 1919 speech is a paean to the humanities, but also a potential eulogy. As a Victorian physician, Osler was a blend of the new science and the old humanities. He knew that “the old art cannot possibly be replaced by, but must be absorbed in, the new science.”³⁵ Yet he could also see the upcoming split between the two cultures, and he tried to warn us. He could in fact foresee the end of an entire way of life. As he said in his address, “there must be a very different civilization or there will be no civilization at all.”¹

The crisis we face in medicine today may indeed be a symptom of a much larger cultural shift. As Osler himself put it, “The philosophies of one age have become the absurdities of the next, and the foolishness of yesterday has become the wisdom of tomorrow.”³³ Like Osler, we live in times of transition that require us to act. If in 1910 Flexner gave us science,³⁷ Osler in 1919 reminded us that medicine also needs the humanities. We ought to heed his message and reconcile the two fields. The alternative is a future full of tricorders and burned-out technicians, but sorely lacking in healers.

To the Editor: Regarding the article about a man with rapidly progressive pleural effusion by Zoumot et al in the January 2019 issue,¹ there was some inconsistency between the teaching points and the actions taken.

Question 1 asked what was the most likely cause of the patient’s pleuritic chest pain. Pulmonary embolism was an unlikely diagnosis, given the patient’s presentation and his normal D-dimer level, which the text acknowledges, but then proceeds to state that computed tomographic angiography of the chest was done anyway.

After pleural effusion was diagnosed, question 2 asked what was the best management strategy for the patient at that time. The best management strategy was to give oral antibiotics with close follow-up because the patient was at low risk of a poor outcome, but he was advised to be admitted for intravenous antibiotics anyway.

I’m not quite sure of the point of the didactic exercise when actions are not consistent with the analytic rationale for testing and treatment.

To the Editor: Regarding the article about a man with rapidly progressive pleural effusion by Zoumot et al in the January 2019 issue,¹ there was some inconsistency between the teaching points and the actions taken.

Question 1 asked what was the most likely cause of the patient’s pleuritic chest pain. Pulmonary embolism was an unlikely diagnosis, given the patient’s presentation and his normal D-dimer level, which the text acknowledges, but then proceeds to state that computed tomographic angiography of the chest was done anyway.

After pleural effusion was diagnosed, question 2 asked what was the best management strategy for the patient at that time. The best management strategy was to give oral antibiotics with close follow-up because the patient was at low risk of a poor outcome, but he was advised to be admitted for intravenous antibiotics anyway.

I’m not quite sure of the point of the didactic exercise when actions are not consistent with the analytic rationale for testing and treatment.

To the Editor: Regarding the article about a man with rapidly progressive pleural effusion by Zoumot et al in the January 2019 issue,¹ there was some inconsistency between the teaching points and the actions taken.

Question 1 asked what was the most likely cause of the patient’s pleuritic chest pain. Pulmonary embolism was an unlikely diagnosis, given the patient’s presentation and his normal D-dimer level, which the text acknowledges, but then proceeds to state that computed tomographic angiography of the chest was done anyway.

After pleural effusion was diagnosed, question 2 asked what was the best management strategy for the patient at that time. The best management strategy was to give oral antibiotics with close follow-up because the patient was at low risk of a poor outcome, but he was advised to be admitted for intravenous antibiotics anyway.

I’m not quite sure of the point of the didactic exercise when actions are not consistent with the analytic rationale for testing and treatment.