Imaging

Idiopathic pulmonary fibrosis (IPF) is a devastating and fatal lung disease that generally affects older adults. It is characterized by a radiographic and histopathologic pattern of usual interstitial pneumonia (UIP) that has no other known etiology.

See related editorial

Accurate diagnosis of IPF is crucial. We recommend early referral to a center specializing in interstitial lung disease to confirm the diagnosis, start appropriate therapy, advise the patient on prognosis and enrollment in disease registries and clinical trials, and determine candidacy for lung transplant.

Primary care physicians are uniquely positioned to encounter patients with IPF, whether because of a patient complaint or as an incidental finding on computed tomography. The goal of this article is to delineate the features of IPF so that it may be recognized early and thus expedite referral to a center with expertise in interstitial lung disease for a thorough evaluation and appropriate management.

WHAT IS IDIOPATHIC PULMONARY FIBROSIS?

MORE COMMON THAN ONCE THOUGHT

The true incidence and prevalence of IPF are difficult to assess. IPF is generally considered a rare disease, but it is more common than once thought. In 2011, Raghu et al³ estimated the prevalence in Medicare beneficiaries to be 495 cases per 100,000. Based on this estimate and the current US population, up to 160,000 Americans could have IPF.⁴ Raghu et al also showed that IPF more often affects adults over age 65, which suggests that as the US population ages, the incidence of IPF may rise. Studies have also reported an increased incidence of IPF worldwide.⁵

Further, with the rising use of low-dose computed tomography to screen for lung cancer, more incidental cases of IPF will likely be found.^6–8

Older data showed a lag from symptom onset to accurate diagnosis of 1 to 2 years.⁹ A more recent study found a lag in referral of patients with IPF to tertiary care centers, and this delay was associated with a higher rate of death independent of disease severity.¹⁰

TYPICALLY PROGRESSIVE, OFTEN FATAL

IPF is typically progressive and limited to the lungs, and it portends a poor prognosis. The median survival is commonly cited as 2 to 5 years from diagnosis, although this is based on older observations that may not reflect current best practice and newer therapies. More recent studies suggest higher survival rates if patients have preserved lung function.¹¹

As the name indicates, the etiology of IPF is unknown, but studies have indicated genetic underpinnings in a notable proportion of cases.¹² Regardless of the cause, the pathogenesis and progression of IPF are thought to be the result of an abnormal and persistent wound-repair response. The progressive deposition of scar tissue disrupts normal lung architecture and function, eventually causing clinical disease.¹³

SYMPTOMS AND KEY FEATURES

Patients with IPF typically present with the insidious onset of dyspnea on exertion, with or without chronic cough. Risk factors include male sex, increasing age, and a history of smoking. Patients with undiagnosed IPF who present with dyspnea and a history of smoking are often treated empirically for chronic obstructive pulmonary disease (COPD).

Rales are a common finding on auscultation in IPF, and this can lead to an exhaustive cardiac evaluation and empiric treatment for heart failure. Digital clubbing is also relatively common.¹⁴ Hypoxemia with exertion is another common feature that also often correlates with disease severity and prognosis. Resting hypoxemia is more common in advanced disease.

On spirometry, patients with IPF typically demonstrate restrictive physiology, suggested by a normal or elevated ratio of the forced expiratory volume in 1 second to the forced vital capacity (FEV₁/FVC) (> 70% predicted or above the lower limit of normal) combined with a lower than normal FVC. Restrictive physiology is definitively demonstrated by a decreased total lung capacity (< 80% predicted or below the lower limit of normal) on plethysmography. Impaired gas exchange, manifested by a decreased diffusing capacity of the lungs for carbon monoxide (DLCO) on pulmonary function testing, is also common. Because pulmonary perfusion is higher in the lung bases, where IPF is also predominant, the DLCO is often reduced to a greater extent than the FVC.

PROGNOSTIC INDICATORS

Clinicians typically view IPF as a relentless and progressive process, but its course is variable and can be uncertain in an individual patient (Figure 1).^15,16 Nevertheless, over time, most patients have a decline in lung function leading to respiratory failure. Respiratory failure, often preceded by a subacute deterioration (over weeks to months) or an acute deterioration (< 4 weeks), is the most common cause of death, but comorbid diseases such as lung cancer, infection, and heart failure are also common causes of death in these patients.^17,18

Predictors of mortality include worsening FVC, DLCO, symptoms, and physiologic impairment, manifested by a decline in the 6-minute walking test or worsening exertional hypoxemia.^19–22 Other common comorbidities linked with impaired quality of life and poor prognosis include obstructive sleep apnea, gastroesophageal reflux disease, and depression.^16,23 Retrospective studies suggest that most IPF patients die 2 to 5 years after symptom onset. With the lag from symptom onset to final diagnosis, the average life expectancy is as little as 2 years from the time of diagnosis.^9,18,24,25

Two staging systems have been developed to predict short-term and long-term mortality risk based on sex, age, and physiologic parameters.^23,24 The GAP (gender, age, physiology) index provides an estimate of the risk of death for a cohort of patients: a score of 0 to 8 is calculated, and the score is then categorized as stage I, II, or III. Each stage is associated with 1-, 2-, and 3-year mortality rates, with stage III having the highest rates. The GAP calculator (www.acponline.org/journals/annals/extras/gap) provides an estimate of the risk of death for an individual patient. The application of these tools for the management of IPF is evolving; however, they may be helpful for counseling patients about disease prognosis.

CLUES TO DIAGNOSIS

Histologic patterns

UIP on histologic study is also seen in fibrotic lung diseases other than IPF, including connective tissue disease-associated interstitial lung disease, inhalational or occupational interstitial lung disease, and chronic hypersensitivity pneumonitis.^26–29 Consequently, the diagnosis of IPF requires exclusion of other known causes of UIP.

According to the 2011 guidelines,¹⁶ the histology of interstitial lung disease can be categorized as definite UIP, probable UIP, or possible UIP, or as an atypical pattern suggesting another diagnosis. If no definite cause of the interstitial lung abnormality is found, the level of certainty of the histopathologic pattern of UIP helps formulate the clinical diagnosis and management plan.

Clues on computed tomography

The UIP nomenclature also describes patterns on high-resolution computed tomography (HRCT). HRCT is done without contrast and produces thin-sliced images (usually < 1.5 mm) in inspiratory, expiratory, and prone views; this allows detection of air trapping, which may indicate an airway-centric alternative diagnosis.

On HRCT, UIP appears as reticular opacities, often with traction bronchiectasis or bronchiolectasis, usually with a basilar and peripheral predominance. Honeycombing is a key feature and appears as clustered cystic spaces with well-defined walls in the periphery of the lung parenchyma. Ground-glass opacities are not a prominent feature of UIP, and although they do not exclude a UIP pattern, they should spur consideration of other diagnoses.¹⁶ Reactive mediastinal and hilar lymphadenopathy is another common feature of UIP.

When evaluating results of HRCT for UIP, the radiologist categorizes the pattern as definite UIP, possible UIP, or inconsistent. The definite pattern meets all the above features and has none of the features suggesting an alternative diagnosis (Figure 3). The possible pattern includes all the above features with the exception of honeycombing. If the predominant features on HRCT include any atypical finding listed above, then the study is considered inconsistent with UIP. If the pattern on HRCT is considered definite, evaluation of pathology is not necessary. If the pattern is categorized as possible or is inconsistent, then surgical lung biopsy-confirmed UIP is necessary for the definitive diagnosis of IPF.

However, evidence is emerging that in the correct clinical scenario, possible UIP behaves similarly to definite UIP and may be sufficient to make the clinical diagnosis of IPF even without surgical biopsy confirmation.³⁰

A DIAGNOSTIC ALGORITHM FOR IPF

Given the multitude of interstitial lung diseases, their complexities, and the lack of a gold standard definitive diagnostic test, the diagnosis of IPF can be difficult, requiring the integration of clinical, radiologic, and, if necessary, pathologic findings.

Demographic features

The patient’s demographic features and risk factors dictate the initial clinical suspicion of IPF compared with other interstitial lung diseases. The incidence of IPF increases with age, and IPF is more common in men. A history of smoking is another risk factor.³¹ A 45-year-old never-smoker is much less likely to have IPF than a 70-year-old former smoker, and a 70-year-old man is more likely to have IPF than a woman of the same age. Thus, the finding of interstitial lung disease in a patient with a demographic profile that is not typical (ie, a younger woman who never smoked) should prompt an exhaustive investigation for another diagnosis such as hypersensitivity pneumonitis or connective tissue disease.

Key elements of the history

After considering the demographic profile and risk factors, the next step in the evaluation is a thorough and accurate medical history. This should include assessment of the severity of dyspnea and cough, signs and symptoms of connective tissue disease (eg, arthralgias, sicca symptoms, Raynaud phenomenon, difficulty swallowing), and gastroesophageal reflux disease, which can be associated with connective tissue disease and, independently, with IPF.

It is also important to identify any environmental exposures that suggest pneumoconiosis or chronic hypersensitivity pneumonitis. The most common risk factors for hypersensitivity pneumonitis are birds and bird feathers, molds, fungi, hot tub use, and some industrial chemicals.³²

A medication history is important. Many medications are associated with interstitial lung disease, but amiodarone, bleomycin, methotrexate, and nitrofurantoin are among the common offenders.³³

A thorough family history is necessary, as there are familial forms of IPF.

Focus of the physical examination

The physical examination must include careful auscultation for rales. While rales are not specific for IPF, they are the most common pulmonary abnormality. Detailed skin, musculoskeletal, and cardiovascular examinations are also important to evaluate for rheumatologic signs, clubbing, or evidence of heart failure or pulmonary hypertension.

Laboratory tests

Laboratory testing should include a serologic autoantibody panel to evaluate for connective tissue diseases that can manifest as interstitial lung disease, including rheumatoid arthritis, dermatopolymyositis, scleroderma, Sjögren syndrome, and undifferentiated or mixed connective tissue disease. Typical preliminary laboratory tests are antinuclear antibody, rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein. Others may include anticyclic citrullinated peptide (anti-CCP), anti-Scl-70, anti-RNP, anti-SS-A, anti-SS-B, and anti-Jo-1.¹⁶ The breadth of the panel should depend on patient demographics and findings in the history or physical examination that increase or decrease the likelihood of a connective tissue disease.

Lung function testing

Assessing the patient’s pulmonary physiology should include spirometry, DLCO, and body plethysmography (lung volumes). In most cases, IPF manifests with restrictive physiology. Once restrictive physiology is confirmed with a low total lung capacity, FVC testing can be used as a longitudinal surrogate, as it is less expensive and easier for the patient to perform. In general, a lower total lung capacity or FVC indicates more severe impairment.

The DLCO serves as another marker of severity but is less reliable due to baseline variability and difficulties performing the maneuver.

A 6-minute walk test is another crucial physiologic assessment tool that can quantify exertional hypoxemia and functional status (ie, distance walked), and can assist in prognosis.

Imaging

Most patients undergo chest radiography in the workup for undiagnosed dyspnea. However, chest radiography is not adequate to formulate an accurate diagnosis in suspected interstitial lung disease, and a normal radiograph cannot exclude changes that might reflect early phases of the disease. As the disease progresses, the plain radiograph can show reticulonodular opacities and honeycombing in the peripheral and lower lung zones (Figure 3).³⁴

The decision whether to order HRCT in the workup for a patient who has dyspnea and a normal chest radiograph is challenging. We recommend cross-sectional imaging when physiologic testing shows restriction or low DLCO, or when there is a high index of suspicion for underlying lung disease as the cause of symptoms.

Expert consultation can aid with this decision, especially when the underlying cause of dyspnea remains unclear after initial studies have been completed. Otherwise, HRCT is an essential test in the evaluation of interstitial lung disease.

Bronchoscopy’s role controversial

If the pattern on HRCT is nondiagnostic, then surgical biopsy is necessary, and the diagnosis of IPF requires a histologic pattern of UIP as described above.^16,35

Although bronchoscopy can be valuable if an alternative diagnosis such as sarcoidosis or chronic hypersensitivity pneumonitis is suspected, the role of bronchoscopic biopsy in the workup of IPF is controversial. The patchy nature of UIP does not lend itself to the relatively small biopsy samples obtained through bronchoscopy.^36,37

Surgical biopsy options

The favored biopsy approach is surgical, using either an open or a video-assisted thoracoscopic technique. The latter is preferred as it is less invasive, requires a shorter length of hospital stay, and allows a faster recovery.³⁸ Bronchoscopic cryobiopsy, currently under investigation, is a potentially valuable tool whose role in diagnosing IPF is evolving.

Frequently, neither HRCT nor surgical lung biopsy demonstrates UIP, making the definitive diagnosis of IPF difficult. Moreover, some patients with nondiagnostic HRCT results are unable to tolerate surgical lung biopsy because of severely impaired lung function or other comorbidities.

The role of multidisciplinary discussions

When surgical lung biopsy is not possible, current practice at leading centers uses a multidisciplinary approach to allow for a confident diagnosis.^30,39 Discussions take place between pulmonologists, pathologists, radiologists, and other specialists to collectively consider all aspects of a case before rendering a consensus opinion on the diagnosis and the management plan. If the discussion leads to a consensus diagnosis of IPF, then the patient’s clinician can move forward with treatment options. If not, the group can recommend further workup or alternative diagnoses and treatment regimens. The multidisciplinary group is also well positioned to consider the relative risks and benefits of moving forward with surgical lung biopsy for individual patients.

This approach illustrates the importance of referring these patients to centers of excellence in diagnosing and managing complex cases of interstitial lung disease, including IPF.⁴⁰

TREATMENT OF IPF

Antifibrotic therapy

Antifibrotic therapy is a choice between pirfenidone and nintedanib.

Pirfenidone, which has an undefined molecular target, was approved based on the results of 3 trials.^41,42 Pooled analyses from these trials showed a reduction in the decline from baseline in FVC percent predicted and improved progression-free survival.⁴³ Pooled and meta-analyses of pirfenidone clinical trials have shown a mortality benefit, although no individual study has shown such an effect on mortality rates.⁴⁴

The major adverse effects of pirfenidone are gastrointestinal distress and photosensitivity rash.

Nintedanib is a triple tyrosine kinase inhibitor that broadly targets fibroblast growth factor, vascular endothelial growth factor, and platelet-derived growth factor receptors. Combined analysis of 2 concurrent trials⁴⁵ showed that nintedanib reduced the decline in FVC, similarly to pirfenidone. The major adverse event associated with nintedanib was diarrhea. Since it inhibits vascular endothelial growth factor, there is a risk of hematologic complications such as bleeding or clotting events.

Because pirfenidone and nintedanib can increase aminotransferase levels, regular monitoring is recommended.

To date, no trial has compared pirfenidone and nintedanib in terms of their efficacy and tolerability. Therefore, the choice of agent is based on the patient’s preference after a discussion of potential risks and expected benefits, a review of each drug’s side effects, and consideration of comorbid conditions and physician experience.

Patients need to understand that these drugs slow the rate of decline in FVC but have not been shown to improve symptoms or functional status.

Corticosteroids are not routine

Corticosteroids should not be used routinely in the treatment of IPF. Although steroids, alone or in combination with other immunosuppressive medications, were commonly used for IPF in the past, such use was not based on results of randomized controlled trials.⁴⁶ Retrospective controlled studies have failed to show that corticosteroids improve mortality rates in IPF; indeed, they have shown that corticosteroids confer substantial morbidity.^47,48 In addition, a randomized controlled trial combining corticosteroids with N-acetylcysteine and azathioprine was stopped early due to an increased risk of death and hospitalization.⁴⁹ Collectively, these data suggest that corticosteroids confer no benefit and are potentially harmful. Their use in IPF is discouraged, and the joint international guidelines recommend against immunosuppression to treat IPF.¹⁶

Other treatments

The guidelines offer additional suggestions for the management of IPF.

Preliminary evidence suggests that microaspiration associated with abnormal gastroesophageal acid reflux is a risk factor for IPF. As such, there is a weak recommendation for aggressive treatment of reflux disease.⁵⁰ However, because evidence suggests that proton-pump inhibitor therapy may be associated with adverse renal or central nervous system effects, this recommendation bears caution. It is hoped that ongoing studies will provide further insight into the role of acid-suppression in the management of IPF.^51,52

Further treatment recommendations include best supportive management such as supplemental oxygen, pulmonary rehabilitation, and vaccinations.

Prompt referral for lung transplant is imperative. IPF is now the most common indication for lung transplant, and given the poor overall prognosis of advanced IPF, transplant confers a survival benefit in appropriately selected patients.^53,54 Table 2 provides an evidence-based checklist for the workup and management of IPF.

ACUTE EXACERBATIONS OF IPF

The unpredictable nature of IPF can manifest in the form of acute exacerbations without an identifiable cause. The loosely defined diagnostic criteria for the diagnosis of acute exacerbations are a previous or new diagnosis of IPF, worsening or development of dyspnea in the last 30 days, and new bilateral ground-glass or consolidative changes with a background of UIP on HRCT.¹⁶

A new definition has been proposed⁵⁵ to facilitate research in the characterization and treatment of acute exacerbations of IPF. The new definition includes all causes of respiratory deterioration except for heart failure and volume overload. It is less strict about the 30-day time frame. This newer definition is based on the lack of evidence differentiating outcomes when an acute deterioration is associated with known or unknown etiologies.⁵⁵

The incidence of acute exacerbations is variable, with a 1- and 3-year incidence ranging between 8.6% and 23.9% depending on the criteria used.⁵⁶ In general, acute exacerbations carry a grim prognosis, with a median life expectancy of 2.2 months.⁵⁷

There is no approved therapy for exacerbations of IPF. Rather, treatment is mainly supportive with supplemental oxygen and mechanical ventilation. Current guidelines have a weak recommendation for the use of corticosteroids, but there are no recommendations regarding dose, route, or duration of therapy. Other treatments, primarily immunomodulatory agents, have been suggested but lack evidence of benefit.

Acknowledgments: Pathology images were provided by Carol Farver, MD, Pathology Institute, Cleveland Clinic. Radiology images were provided by Ruchi Yadav, MD, Imaging Institute, Cleveland Clinic.

Idiopathic pulmonary fibrosis (IPF) is a devastating and fatal lung disease that generally affects older adults. It is characterized by a radiographic and histopathologic pattern of usual interstitial pneumonia (UIP) that has no other known etiology.

See related editorial

Accurate diagnosis of IPF is crucial. We recommend early referral to a center specializing in interstitial lung disease to confirm the diagnosis, start appropriate therapy, advise the patient on prognosis and enrollment in disease registries and clinical trials, and determine candidacy for lung transplant.

Primary care physicians are uniquely positioned to encounter patients with IPF, whether because of a patient complaint or as an incidental finding on computed tomography. The goal of this article is to delineate the features of IPF so that it may be recognized early and thus expedite referral to a center with expertise in interstitial lung disease for a thorough evaluation and appropriate management.

WHAT IS IDIOPATHIC PULMONARY FIBROSIS?

MORE COMMON THAN ONCE THOUGHT

The true incidence and prevalence of IPF are difficult to assess. IPF is generally considered a rare disease, but it is more common than once thought. In 2011, Raghu et al³ estimated the prevalence in Medicare beneficiaries to be 495 cases per 100,000. Based on this estimate and the current US population, up to 160,000 Americans could have IPF.⁴ Raghu et al also showed that IPF more often affects adults over age 65, which suggests that as the US population ages, the incidence of IPF may rise. Studies have also reported an increased incidence of IPF worldwide.⁵

Further, with the rising use of low-dose computed tomography to screen for lung cancer, more incidental cases of IPF will likely be found.^6–8

Older data showed a lag from symptom onset to accurate diagnosis of 1 to 2 years.⁹ A more recent study found a lag in referral of patients with IPF to tertiary care centers, and this delay was associated with a higher rate of death independent of disease severity.¹⁰

TYPICALLY PROGRESSIVE, OFTEN FATAL

IPF is typically progressive and limited to the lungs, and it portends a poor prognosis. The median survival is commonly cited as 2 to 5 years from diagnosis, although this is based on older observations that may not reflect current best practice and newer therapies. More recent studies suggest higher survival rates if patients have preserved lung function.¹¹

As the name indicates, the etiology of IPF is unknown, but studies have indicated genetic underpinnings in a notable proportion of cases.¹² Regardless of the cause, the pathogenesis and progression of IPF are thought to be the result of an abnormal and persistent wound-repair response. The progressive deposition of scar tissue disrupts normal lung architecture and function, eventually causing clinical disease.¹³

SYMPTOMS AND KEY FEATURES

Patients with IPF typically present with the insidious onset of dyspnea on exertion, with or without chronic cough. Risk factors include male sex, increasing age, and a history of smoking. Patients with undiagnosed IPF who present with dyspnea and a history of smoking are often treated empirically for chronic obstructive pulmonary disease (COPD).

Rales are a common finding on auscultation in IPF, and this can lead to an exhaustive cardiac evaluation and empiric treatment for heart failure. Digital clubbing is also relatively common.¹⁴ Hypoxemia with exertion is another common feature that also often correlates with disease severity and prognosis. Resting hypoxemia is more common in advanced disease.

On spirometry, patients with IPF typically demonstrate restrictive physiology, suggested by a normal or elevated ratio of the forced expiratory volume in 1 second to the forced vital capacity (FEV₁/FVC) (> 70% predicted or above the lower limit of normal) combined with a lower than normal FVC. Restrictive physiology is definitively demonstrated by a decreased total lung capacity (< 80% predicted or below the lower limit of normal) on plethysmography. Impaired gas exchange, manifested by a decreased diffusing capacity of the lungs for carbon monoxide (DLCO) on pulmonary function testing, is also common. Because pulmonary perfusion is higher in the lung bases, where IPF is also predominant, the DLCO is often reduced to a greater extent than the FVC.

PROGNOSTIC INDICATORS

Clinicians typically view IPF as a relentless and progressive process, but its course is variable and can be uncertain in an individual patient (Figure 1).^15,16 Nevertheless, over time, most patients have a decline in lung function leading to respiratory failure. Respiratory failure, often preceded by a subacute deterioration (over weeks to months) or an acute deterioration (< 4 weeks), is the most common cause of death, but comorbid diseases such as lung cancer, infection, and heart failure are also common causes of death in these patients.^17,18

Predictors of mortality include worsening FVC, DLCO, symptoms, and physiologic impairment, manifested by a decline in the 6-minute walking test or worsening exertional hypoxemia.^19–22 Other common comorbidities linked with impaired quality of life and poor prognosis include obstructive sleep apnea, gastroesophageal reflux disease, and depression.^16,23 Retrospective studies suggest that most IPF patients die 2 to 5 years after symptom onset. With the lag from symptom onset to final diagnosis, the average life expectancy is as little as 2 years from the time of diagnosis.^9,18,24,25

Two staging systems have been developed to predict short-term and long-term mortality risk based on sex, age, and physiologic parameters.^23,24 The GAP (gender, age, physiology) index provides an estimate of the risk of death for a cohort of patients: a score of 0 to 8 is calculated, and the score is then categorized as stage I, II, or III. Each stage is associated with 1-, 2-, and 3-year mortality rates, with stage III having the highest rates. The GAP calculator (www.acponline.org/journals/annals/extras/gap) provides an estimate of the risk of death for an individual patient. The application of these tools for the management of IPF is evolving; however, they may be helpful for counseling patients about disease prognosis.

CLUES TO DIAGNOSIS

Histologic patterns

UIP on histologic study is also seen in fibrotic lung diseases other than IPF, including connective tissue disease-associated interstitial lung disease, inhalational or occupational interstitial lung disease, and chronic hypersensitivity pneumonitis.^26–29 Consequently, the diagnosis of IPF requires exclusion of other known causes of UIP.

According to the 2011 guidelines,¹⁶ the histology of interstitial lung disease can be categorized as definite UIP, probable UIP, or possible UIP, or as an atypical pattern suggesting another diagnosis. If no definite cause of the interstitial lung abnormality is found, the level of certainty of the histopathologic pattern of UIP helps formulate the clinical diagnosis and management plan.

Clues on computed tomography

The UIP nomenclature also describes patterns on high-resolution computed tomography (HRCT). HRCT is done without contrast and produces thin-sliced images (usually < 1.5 mm) in inspiratory, expiratory, and prone views; this allows detection of air trapping, which may indicate an airway-centric alternative diagnosis.

On HRCT, UIP appears as reticular opacities, often with traction bronchiectasis or bronchiolectasis, usually with a basilar and peripheral predominance. Honeycombing is a key feature and appears as clustered cystic spaces with well-defined walls in the periphery of the lung parenchyma. Ground-glass opacities are not a prominent feature of UIP, and although they do not exclude a UIP pattern, they should spur consideration of other diagnoses.¹⁶ Reactive mediastinal and hilar lymphadenopathy is another common feature of UIP.

When evaluating results of HRCT for UIP, the radiologist categorizes the pattern as definite UIP, possible UIP, or inconsistent. The definite pattern meets all the above features and has none of the features suggesting an alternative diagnosis (Figure 3). The possible pattern includes all the above features with the exception of honeycombing. If the predominant features on HRCT include any atypical finding listed above, then the study is considered inconsistent with UIP. If the pattern on HRCT is considered definite, evaluation of pathology is not necessary. If the pattern is categorized as possible or is inconsistent, then surgical lung biopsy-confirmed UIP is necessary for the definitive diagnosis of IPF.

However, evidence is emerging that in the correct clinical scenario, possible UIP behaves similarly to definite UIP and may be sufficient to make the clinical diagnosis of IPF even without surgical biopsy confirmation.³⁰

A DIAGNOSTIC ALGORITHM FOR IPF

Given the multitude of interstitial lung diseases, their complexities, and the lack of a gold standard definitive diagnostic test, the diagnosis of IPF can be difficult, requiring the integration of clinical, radiologic, and, if necessary, pathologic findings.

Demographic features

The patient’s demographic features and risk factors dictate the initial clinical suspicion of IPF compared with other interstitial lung diseases. The incidence of IPF increases with age, and IPF is more common in men. A history of smoking is another risk factor.³¹ A 45-year-old never-smoker is much less likely to have IPF than a 70-year-old former smoker, and a 70-year-old man is more likely to have IPF than a woman of the same age. Thus, the finding of interstitial lung disease in a patient with a demographic profile that is not typical (ie, a younger woman who never smoked) should prompt an exhaustive investigation for another diagnosis such as hypersensitivity pneumonitis or connective tissue disease.

Key elements of the history

After considering the demographic profile and risk factors, the next step in the evaluation is a thorough and accurate medical history. This should include assessment of the severity of dyspnea and cough, signs and symptoms of connective tissue disease (eg, arthralgias, sicca symptoms, Raynaud phenomenon, difficulty swallowing), and gastroesophageal reflux disease, which can be associated with connective tissue disease and, independently, with IPF.

It is also important to identify any environmental exposures that suggest pneumoconiosis or chronic hypersensitivity pneumonitis. The most common risk factors for hypersensitivity pneumonitis are birds and bird feathers, molds, fungi, hot tub use, and some industrial chemicals.³²

A medication history is important. Many medications are associated with interstitial lung disease, but amiodarone, bleomycin, methotrexate, and nitrofurantoin are among the common offenders.³³

A thorough family history is necessary, as there are familial forms of IPF.

Focus of the physical examination

The physical examination must include careful auscultation for rales. While rales are not specific for IPF, they are the most common pulmonary abnormality. Detailed skin, musculoskeletal, and cardiovascular examinations are also important to evaluate for rheumatologic signs, clubbing, or evidence of heart failure or pulmonary hypertension.

Laboratory tests

Laboratory testing should include a serologic autoantibody panel to evaluate for connective tissue diseases that can manifest as interstitial lung disease, including rheumatoid arthritis, dermatopolymyositis, scleroderma, Sjögren syndrome, and undifferentiated or mixed connective tissue disease. Typical preliminary laboratory tests are antinuclear antibody, rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein. Others may include anticyclic citrullinated peptide (anti-CCP), anti-Scl-70, anti-RNP, anti-SS-A, anti-SS-B, and anti-Jo-1.¹⁶ The breadth of the panel should depend on patient demographics and findings in the history or physical examination that increase or decrease the likelihood of a connective tissue disease.

Lung function testing

Assessing the patient’s pulmonary physiology should include spirometry, DLCO, and body plethysmography (lung volumes). In most cases, IPF manifests with restrictive physiology. Once restrictive physiology is confirmed with a low total lung capacity, FVC testing can be used as a longitudinal surrogate, as it is less expensive and easier for the patient to perform. In general, a lower total lung capacity or FVC indicates more severe impairment.

The DLCO serves as another marker of severity but is less reliable due to baseline variability and difficulties performing the maneuver.

A 6-minute walk test is another crucial physiologic assessment tool that can quantify exertional hypoxemia and functional status (ie, distance walked), and can assist in prognosis.

Imaging

Most patients undergo chest radiography in the workup for undiagnosed dyspnea. However, chest radiography is not adequate to formulate an accurate diagnosis in suspected interstitial lung disease, and a normal radiograph cannot exclude changes that might reflect early phases of the disease. As the disease progresses, the plain radiograph can show reticulonodular opacities and honeycombing in the peripheral and lower lung zones (Figure 3).³⁴

The decision whether to order HRCT in the workup for a patient who has dyspnea and a normal chest radiograph is challenging. We recommend cross-sectional imaging when physiologic testing shows restriction or low DLCO, or when there is a high index of suspicion for underlying lung disease as the cause of symptoms.

Expert consultation can aid with this decision, especially when the underlying cause of dyspnea remains unclear after initial studies have been completed. Otherwise, HRCT is an essential test in the evaluation of interstitial lung disease.

Bronchoscopy’s role controversial

If the pattern on HRCT is nondiagnostic, then surgical biopsy is necessary, and the diagnosis of IPF requires a histologic pattern of UIP as described above.^16,35

Although bronchoscopy can be valuable if an alternative diagnosis such as sarcoidosis or chronic hypersensitivity pneumonitis is suspected, the role of bronchoscopic biopsy in the workup of IPF is controversial. The patchy nature of UIP does not lend itself to the relatively small biopsy samples obtained through bronchoscopy.^36,37

Surgical biopsy options

The favored biopsy approach is surgical, using either an open or a video-assisted thoracoscopic technique. The latter is preferred as it is less invasive, requires a shorter length of hospital stay, and allows a faster recovery.³⁸ Bronchoscopic cryobiopsy, currently under investigation, is a potentially valuable tool whose role in diagnosing IPF is evolving.

Frequently, neither HRCT nor surgical lung biopsy demonstrates UIP, making the definitive diagnosis of IPF difficult. Moreover, some patients with nondiagnostic HRCT results are unable to tolerate surgical lung biopsy because of severely impaired lung function or other comorbidities.

The role of multidisciplinary discussions

When surgical lung biopsy is not possible, current practice at leading centers uses a multidisciplinary approach to allow for a confident diagnosis.^30,39 Discussions take place between pulmonologists, pathologists, radiologists, and other specialists to collectively consider all aspects of a case before rendering a consensus opinion on the diagnosis and the management plan. If the discussion leads to a consensus diagnosis of IPF, then the patient’s clinician can move forward with treatment options. If not, the group can recommend further workup or alternative diagnoses and treatment regimens. The multidisciplinary group is also well positioned to consider the relative risks and benefits of moving forward with surgical lung biopsy for individual patients.

This approach illustrates the importance of referring these patients to centers of excellence in diagnosing and managing complex cases of interstitial lung disease, including IPF.⁴⁰

TREATMENT OF IPF

Antifibrotic therapy

Antifibrotic therapy is a choice between pirfenidone and nintedanib.

Pirfenidone, which has an undefined molecular target, was approved based on the results of 3 trials.^41,42 Pooled analyses from these trials showed a reduction in the decline from baseline in FVC percent predicted and improved progression-free survival.⁴³ Pooled and meta-analyses of pirfenidone clinical trials have shown a mortality benefit, although no individual study has shown such an effect on mortality rates.⁴⁴

The major adverse effects of pirfenidone are gastrointestinal distress and photosensitivity rash.

Nintedanib is a triple tyrosine kinase inhibitor that broadly targets fibroblast growth factor, vascular endothelial growth factor, and platelet-derived growth factor receptors. Combined analysis of 2 concurrent trials⁴⁵ showed that nintedanib reduced the decline in FVC, similarly to pirfenidone. The major adverse event associated with nintedanib was diarrhea. Since it inhibits vascular endothelial growth factor, there is a risk of hematologic complications such as bleeding or clotting events.

Because pirfenidone and nintedanib can increase aminotransferase levels, regular monitoring is recommended.

To date, no trial has compared pirfenidone and nintedanib in terms of their efficacy and tolerability. Therefore, the choice of agent is based on the patient’s preference after a discussion of potential risks and expected benefits, a review of each drug’s side effects, and consideration of comorbid conditions and physician experience.

Patients need to understand that these drugs slow the rate of decline in FVC but have not been shown to improve symptoms or functional status.

Corticosteroids are not routine

Corticosteroids should not be used routinely in the treatment of IPF. Although steroids, alone or in combination with other immunosuppressive medications, were commonly used for IPF in the past, such use was not based on results of randomized controlled trials.⁴⁶ Retrospective controlled studies have failed to show that corticosteroids improve mortality rates in IPF; indeed, they have shown that corticosteroids confer substantial morbidity.^47,48 In addition, a randomized controlled trial combining corticosteroids with N-acetylcysteine and azathioprine was stopped early due to an increased risk of death and hospitalization.⁴⁹ Collectively, these data suggest that corticosteroids confer no benefit and are potentially harmful. Their use in IPF is discouraged, and the joint international guidelines recommend against immunosuppression to treat IPF.¹⁶

Other treatments

The guidelines offer additional suggestions for the management of IPF.

Preliminary evidence suggests that microaspiration associated with abnormal gastroesophageal acid reflux is a risk factor for IPF. As such, there is a weak recommendation for aggressive treatment of reflux disease.⁵⁰ However, because evidence suggests that proton-pump inhibitor therapy may be associated with adverse renal or central nervous system effects, this recommendation bears caution. It is hoped that ongoing studies will provide further insight into the role of acid-suppression in the management of IPF.^51,52

Further treatment recommendations include best supportive management such as supplemental oxygen, pulmonary rehabilitation, and vaccinations.

Prompt referral for lung transplant is imperative. IPF is now the most common indication for lung transplant, and given the poor overall prognosis of advanced IPF, transplant confers a survival benefit in appropriately selected patients.^53,54 Table 2 provides an evidence-based checklist for the workup and management of IPF.

ACUTE EXACERBATIONS OF IPF

The unpredictable nature of IPF can manifest in the form of acute exacerbations without an identifiable cause. The loosely defined diagnostic criteria for the diagnosis of acute exacerbations are a previous or new diagnosis of IPF, worsening or development of dyspnea in the last 30 days, and new bilateral ground-glass or consolidative changes with a background of UIP on HRCT.¹⁶

A new definition has been proposed⁵⁵ to facilitate research in the characterization and treatment of acute exacerbations of IPF. The new definition includes all causes of respiratory deterioration except for heart failure and volume overload. It is less strict about the 30-day time frame. This newer definition is based on the lack of evidence differentiating outcomes when an acute deterioration is associated with known or unknown etiologies.⁵⁵

The incidence of acute exacerbations is variable, with a 1- and 3-year incidence ranging between 8.6% and 23.9% depending on the criteria used.⁵⁶ In general, acute exacerbations carry a grim prognosis, with a median life expectancy of 2.2 months.⁵⁷

There is no approved therapy for exacerbations of IPF. Rather, treatment is mainly supportive with supplemental oxygen and mechanical ventilation. Current guidelines have a weak recommendation for the use of corticosteroids, but there are no recommendations regarding dose, route, or duration of therapy. Other treatments, primarily immunomodulatory agents, have been suggested but lack evidence of benefit.

Acknowledgments: Pathology images were provided by Carol Farver, MD, Pathology Institute, Cleveland Clinic. Radiology images were provided by Ruchi Yadav, MD, Imaging Institute, Cleveland Clinic.

Idiopathic pulmonary fibrosis (IPF) is a devastating and fatal lung disease that generally affects older adults. It is characterized by a radiographic and histopathologic pattern of usual interstitial pneumonia (UIP) that has no other known etiology.

See related editorial

Accurate diagnosis of IPF is crucial. We recommend early referral to a center specializing in interstitial lung disease to confirm the diagnosis, start appropriate therapy, advise the patient on prognosis and enrollment in disease registries and clinical trials, and determine candidacy for lung transplant.

Primary care physicians are uniquely positioned to encounter patients with IPF, whether because of a patient complaint or as an incidental finding on computed tomography. The goal of this article is to delineate the features of IPF so that it may be recognized early and thus expedite referral to a center with expertise in interstitial lung disease for a thorough evaluation and appropriate management.

WHAT IS IDIOPATHIC PULMONARY FIBROSIS?

MORE COMMON THAN ONCE THOUGHT

The true incidence and prevalence of IPF are difficult to assess. IPF is generally considered a rare disease, but it is more common than once thought. In 2011, Raghu et al³ estimated the prevalence in Medicare beneficiaries to be 495 cases per 100,000. Based on this estimate and the current US population, up to 160,000 Americans could have IPF.⁴ Raghu et al also showed that IPF more often affects adults over age 65, which suggests that as the US population ages, the incidence of IPF may rise. Studies have also reported an increased incidence of IPF worldwide.⁵

Further, with the rising use of low-dose computed tomography to screen for lung cancer, more incidental cases of IPF will likely be found.^6–8

Older data showed a lag from symptom onset to accurate diagnosis of 1 to 2 years.⁹ A more recent study found a lag in referral of patients with IPF to tertiary care centers, and this delay was associated with a higher rate of death independent of disease severity.¹⁰

TYPICALLY PROGRESSIVE, OFTEN FATAL

IPF is typically progressive and limited to the lungs, and it portends a poor prognosis. The median survival is commonly cited as 2 to 5 years from diagnosis, although this is based on older observations that may not reflect current best practice and newer therapies. More recent studies suggest higher survival rates if patients have preserved lung function.¹¹

As the name indicates, the etiology of IPF is unknown, but studies have indicated genetic underpinnings in a notable proportion of cases.¹² Regardless of the cause, the pathogenesis and progression of IPF are thought to be the result of an abnormal and persistent wound-repair response. The progressive deposition of scar tissue disrupts normal lung architecture and function, eventually causing clinical disease.¹³

SYMPTOMS AND KEY FEATURES

Patients with IPF typically present with the insidious onset of dyspnea on exertion, with or without chronic cough. Risk factors include male sex, increasing age, and a history of smoking. Patients with undiagnosed IPF who present with dyspnea and a history of smoking are often treated empirically for chronic obstructive pulmonary disease (COPD).

Rales are a common finding on auscultation in IPF, and this can lead to an exhaustive cardiac evaluation and empiric treatment for heart failure. Digital clubbing is also relatively common.¹⁴ Hypoxemia with exertion is another common feature that also often correlates with disease severity and prognosis. Resting hypoxemia is more common in advanced disease.

On spirometry, patients with IPF typically demonstrate restrictive physiology, suggested by a normal or elevated ratio of the forced expiratory volume in 1 second to the forced vital capacity (FEV₁/FVC) (> 70% predicted or above the lower limit of normal) combined with a lower than normal FVC. Restrictive physiology is definitively demonstrated by a decreased total lung capacity (< 80% predicted or below the lower limit of normal) on plethysmography. Impaired gas exchange, manifested by a decreased diffusing capacity of the lungs for carbon monoxide (DLCO) on pulmonary function testing, is also common. Because pulmonary perfusion is higher in the lung bases, where IPF is also predominant, the DLCO is often reduced to a greater extent than the FVC.

PROGNOSTIC INDICATORS

Clinicians typically view IPF as a relentless and progressive process, but its course is variable and can be uncertain in an individual patient (Figure 1).^15,16 Nevertheless, over time, most patients have a decline in lung function leading to respiratory failure. Respiratory failure, often preceded by a subacute deterioration (over weeks to months) or an acute deterioration (< 4 weeks), is the most common cause of death, but comorbid diseases such as lung cancer, infection, and heart failure are also common causes of death in these patients.^17,18

Predictors of mortality include worsening FVC, DLCO, symptoms, and physiologic impairment, manifested by a decline in the 6-minute walking test or worsening exertional hypoxemia.^19–22 Other common comorbidities linked with impaired quality of life and poor prognosis include obstructive sleep apnea, gastroesophageal reflux disease, and depression.^16,23 Retrospective studies suggest that most IPF patients die 2 to 5 years after symptom onset. With the lag from symptom onset to final diagnosis, the average life expectancy is as little as 2 years from the time of diagnosis.^9,18,24,25

Two staging systems have been developed to predict short-term and long-term mortality risk based on sex, age, and physiologic parameters.^23,24 The GAP (gender, age, physiology) index provides an estimate of the risk of death for a cohort of patients: a score of 0 to 8 is calculated, and the score is then categorized as stage I, II, or III. Each stage is associated with 1-, 2-, and 3-year mortality rates, with stage III having the highest rates. The GAP calculator (www.acponline.org/journals/annals/extras/gap) provides an estimate of the risk of death for an individual patient. The application of these tools for the management of IPF is evolving; however, they may be helpful for counseling patients about disease prognosis.

CLUES TO DIAGNOSIS

Histologic patterns

UIP on histologic study is also seen in fibrotic lung diseases other than IPF, including connective tissue disease-associated interstitial lung disease, inhalational or occupational interstitial lung disease, and chronic hypersensitivity pneumonitis.^26–29 Consequently, the diagnosis of IPF requires exclusion of other known causes of UIP.

According to the 2011 guidelines,¹⁶ the histology of interstitial lung disease can be categorized as definite UIP, probable UIP, or possible UIP, or as an atypical pattern suggesting another diagnosis. If no definite cause of the interstitial lung abnormality is found, the level of certainty of the histopathologic pattern of UIP helps formulate the clinical diagnosis and management plan.

Clues on computed tomography

The UIP nomenclature also describes patterns on high-resolution computed tomography (HRCT). HRCT is done without contrast and produces thin-sliced images (usually < 1.5 mm) in inspiratory, expiratory, and prone views; this allows detection of air trapping, which may indicate an airway-centric alternative diagnosis.

On HRCT, UIP appears as reticular opacities, often with traction bronchiectasis or bronchiolectasis, usually with a basilar and peripheral predominance. Honeycombing is a key feature and appears as clustered cystic spaces with well-defined walls in the periphery of the lung parenchyma. Ground-glass opacities are not a prominent feature of UIP, and although they do not exclude a UIP pattern, they should spur consideration of other diagnoses.¹⁶ Reactive mediastinal and hilar lymphadenopathy is another common feature of UIP.

When evaluating results of HRCT for UIP, the radiologist categorizes the pattern as definite UIP, possible UIP, or inconsistent. The definite pattern meets all the above features and has none of the features suggesting an alternative diagnosis (Figure 3). The possible pattern includes all the above features with the exception of honeycombing. If the predominant features on HRCT include any atypical finding listed above, then the study is considered inconsistent with UIP. If the pattern on HRCT is considered definite, evaluation of pathology is not necessary. If the pattern is categorized as possible or is inconsistent, then surgical lung biopsy-confirmed UIP is necessary for the definitive diagnosis of IPF.

However, evidence is emerging that in the correct clinical scenario, possible UIP behaves similarly to definite UIP and may be sufficient to make the clinical diagnosis of IPF even without surgical biopsy confirmation.³⁰

A DIAGNOSTIC ALGORITHM FOR IPF

Given the multitude of interstitial lung diseases, their complexities, and the lack of a gold standard definitive diagnostic test, the diagnosis of IPF can be difficult, requiring the integration of clinical, radiologic, and, if necessary, pathologic findings.

Demographic features

The patient’s demographic features and risk factors dictate the initial clinical suspicion of IPF compared with other interstitial lung diseases. The incidence of IPF increases with age, and IPF is more common in men. A history of smoking is another risk factor.³¹ A 45-year-old never-smoker is much less likely to have IPF than a 70-year-old former smoker, and a 70-year-old man is more likely to have IPF than a woman of the same age. Thus, the finding of interstitial lung disease in a patient with a demographic profile that is not typical (ie, a younger woman who never smoked) should prompt an exhaustive investigation for another diagnosis such as hypersensitivity pneumonitis or connective tissue disease.

Key elements of the history

After considering the demographic profile and risk factors, the next step in the evaluation is a thorough and accurate medical history. This should include assessment of the severity of dyspnea and cough, signs and symptoms of connective tissue disease (eg, arthralgias, sicca symptoms, Raynaud phenomenon, difficulty swallowing), and gastroesophageal reflux disease, which can be associated with connective tissue disease and, independently, with IPF.

It is also important to identify any environmental exposures that suggest pneumoconiosis or chronic hypersensitivity pneumonitis. The most common risk factors for hypersensitivity pneumonitis are birds and bird feathers, molds, fungi, hot tub use, and some industrial chemicals.³²

A medication history is important. Many medications are associated with interstitial lung disease, but amiodarone, bleomycin, methotrexate, and nitrofurantoin are among the common offenders.³³

A thorough family history is necessary, as there are familial forms of IPF.

Focus of the physical examination

The physical examination must include careful auscultation for rales. While rales are not specific for IPF, they are the most common pulmonary abnormality. Detailed skin, musculoskeletal, and cardiovascular examinations are also important to evaluate for rheumatologic signs, clubbing, or evidence of heart failure or pulmonary hypertension.

Laboratory tests

Laboratory testing should include a serologic autoantibody panel to evaluate for connective tissue diseases that can manifest as interstitial lung disease, including rheumatoid arthritis, dermatopolymyositis, scleroderma, Sjögren syndrome, and undifferentiated or mixed connective tissue disease. Typical preliminary laboratory tests are antinuclear antibody, rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein. Others may include anticyclic citrullinated peptide (anti-CCP), anti-Scl-70, anti-RNP, anti-SS-A, anti-SS-B, and anti-Jo-1.¹⁶ The breadth of the panel should depend on patient demographics and findings in the history or physical examination that increase or decrease the likelihood of a connective tissue disease.

Lung function testing

Assessing the patient’s pulmonary physiology should include spirometry, DLCO, and body plethysmography (lung volumes). In most cases, IPF manifests with restrictive physiology. Once restrictive physiology is confirmed with a low total lung capacity, FVC testing can be used as a longitudinal surrogate, as it is less expensive and easier for the patient to perform. In general, a lower total lung capacity or FVC indicates more severe impairment.

The DLCO serves as another marker of severity but is less reliable due to baseline variability and difficulties performing the maneuver.

A 6-minute walk test is another crucial physiologic assessment tool that can quantify exertional hypoxemia and functional status (ie, distance walked), and can assist in prognosis.

Imaging

Most patients undergo chest radiography in the workup for undiagnosed dyspnea. However, chest radiography is not adequate to formulate an accurate diagnosis in suspected interstitial lung disease, and a normal radiograph cannot exclude changes that might reflect early phases of the disease. As the disease progresses, the plain radiograph can show reticulonodular opacities and honeycombing in the peripheral and lower lung zones (Figure 3).³⁴

The decision whether to order HRCT in the workup for a patient who has dyspnea and a normal chest radiograph is challenging. We recommend cross-sectional imaging when physiologic testing shows restriction or low DLCO, or when there is a high index of suspicion for underlying lung disease as the cause of symptoms.

Expert consultation can aid with this decision, especially when the underlying cause of dyspnea remains unclear after initial studies have been completed. Otherwise, HRCT is an essential test in the evaluation of interstitial lung disease.

Bronchoscopy’s role controversial

If the pattern on HRCT is nondiagnostic, then surgical biopsy is necessary, and the diagnosis of IPF requires a histologic pattern of UIP as described above.^16,35

Although bronchoscopy can be valuable if an alternative diagnosis such as sarcoidosis or chronic hypersensitivity pneumonitis is suspected, the role of bronchoscopic biopsy in the workup of IPF is controversial. The patchy nature of UIP does not lend itself to the relatively small biopsy samples obtained through bronchoscopy.^36,37

Surgical biopsy options

The favored biopsy approach is surgical, using either an open or a video-assisted thoracoscopic technique. The latter is preferred as it is less invasive, requires a shorter length of hospital stay, and allows a faster recovery.³⁸ Bronchoscopic cryobiopsy, currently under investigation, is a potentially valuable tool whose role in diagnosing IPF is evolving.

Frequently, neither HRCT nor surgical lung biopsy demonstrates UIP, making the definitive diagnosis of IPF difficult. Moreover, some patients with nondiagnostic HRCT results are unable to tolerate surgical lung biopsy because of severely impaired lung function or other comorbidities.

The role of multidisciplinary discussions

When surgical lung biopsy is not possible, current practice at leading centers uses a multidisciplinary approach to allow for a confident diagnosis.^30,39 Discussions take place between pulmonologists, pathologists, radiologists, and other specialists to collectively consider all aspects of a case before rendering a consensus opinion on the diagnosis and the management plan. If the discussion leads to a consensus diagnosis of IPF, then the patient’s clinician can move forward with treatment options. If not, the group can recommend further workup or alternative diagnoses and treatment regimens. The multidisciplinary group is also well positioned to consider the relative risks and benefits of moving forward with surgical lung biopsy for individual patients.

This approach illustrates the importance of referring these patients to centers of excellence in diagnosing and managing complex cases of interstitial lung disease, including IPF.⁴⁰

TREATMENT OF IPF

Antifibrotic therapy

Antifibrotic therapy is a choice between pirfenidone and nintedanib.

Pirfenidone, which has an undefined molecular target, was approved based on the results of 3 trials.^41,42 Pooled analyses from these trials showed a reduction in the decline from baseline in FVC percent predicted and improved progression-free survival.⁴³ Pooled and meta-analyses of pirfenidone clinical trials have shown a mortality benefit, although no individual study has shown such an effect on mortality rates.⁴⁴

The major adverse effects of pirfenidone are gastrointestinal distress and photosensitivity rash.

Nintedanib is a triple tyrosine kinase inhibitor that broadly targets fibroblast growth factor, vascular endothelial growth factor, and platelet-derived growth factor receptors. Combined analysis of 2 concurrent trials⁴⁵ showed that nintedanib reduced the decline in FVC, similarly to pirfenidone. The major adverse event associated with nintedanib was diarrhea. Since it inhibits vascular endothelial growth factor, there is a risk of hematologic complications such as bleeding or clotting events.

Because pirfenidone and nintedanib can increase aminotransferase levels, regular monitoring is recommended.

To date, no trial has compared pirfenidone and nintedanib in terms of their efficacy and tolerability. Therefore, the choice of agent is based on the patient’s preference after a discussion of potential risks and expected benefits, a review of each drug’s side effects, and consideration of comorbid conditions and physician experience.

Patients need to understand that these drugs slow the rate of decline in FVC but have not been shown to improve symptoms or functional status.

Corticosteroids are not routine

Corticosteroids should not be used routinely in the treatment of IPF. Although steroids, alone or in combination with other immunosuppressive medications, were commonly used for IPF in the past, such use was not based on results of randomized controlled trials.⁴⁶ Retrospective controlled studies have failed to show that corticosteroids improve mortality rates in IPF; indeed, they have shown that corticosteroids confer substantial morbidity.^47,48 In addition, a randomized controlled trial combining corticosteroids with N-acetylcysteine and azathioprine was stopped early due to an increased risk of death and hospitalization.⁴⁹ Collectively, these data suggest that corticosteroids confer no benefit and are potentially harmful. Their use in IPF is discouraged, and the joint international guidelines recommend against immunosuppression to treat IPF.¹⁶

Other treatments

The guidelines offer additional suggestions for the management of IPF.

Preliminary evidence suggests that microaspiration associated with abnormal gastroesophageal acid reflux is a risk factor for IPF. As such, there is a weak recommendation for aggressive treatment of reflux disease.⁵⁰ However, because evidence suggests that proton-pump inhibitor therapy may be associated with adverse renal or central nervous system effects, this recommendation bears caution. It is hoped that ongoing studies will provide further insight into the role of acid-suppression in the management of IPF.^51,52

Further treatment recommendations include best supportive management such as supplemental oxygen, pulmonary rehabilitation, and vaccinations.

Prompt referral for lung transplant is imperative. IPF is now the most common indication for lung transplant, and given the poor overall prognosis of advanced IPF, transplant confers a survival benefit in appropriately selected patients.^53,54 Table 2 provides an evidence-based checklist for the workup and management of IPF.

ACUTE EXACERBATIONS OF IPF

The unpredictable nature of IPF can manifest in the form of acute exacerbations without an identifiable cause. The loosely defined diagnostic criteria for the diagnosis of acute exacerbations are a previous or new diagnosis of IPF, worsening or development of dyspnea in the last 30 days, and new bilateral ground-glass or consolidative changes with a background of UIP on HRCT.¹⁶

A new definition has been proposed⁵⁵ to facilitate research in the characterization and treatment of acute exacerbations of IPF. The new definition includes all causes of respiratory deterioration except for heart failure and volume overload. It is less strict about the 30-day time frame. This newer definition is based on the lack of evidence differentiating outcomes when an acute deterioration is associated with known or unknown etiologies.⁵⁵

The incidence of acute exacerbations is variable, with a 1- and 3-year incidence ranging between 8.6% and 23.9% depending on the criteria used.⁵⁶ In general, acute exacerbations carry a grim prognosis, with a median life expectancy of 2.2 months.⁵⁷

There is no approved therapy for exacerbations of IPF. Rather, treatment is mainly supportive with supplemental oxygen and mechanical ventilation. Current guidelines have a weak recommendation for the use of corticosteroids, but there are no recommendations regarding dose, route, or duration of therapy. Other treatments, primarily immunomodulatory agents, have been suggested but lack evidence of benefit.

Acknowledgments: Pathology images were provided by Carol Farver, MD, Pathology Institute, Cleveland Clinic. Radiology images were provided by Ruchi Yadav, MD, Imaging Institute, Cleveland Clinic.

Idiopathic pulmonary fibrosis (IPF) is a devastating progressive fibrosing interstitial lung disease associated with a high burden of morbidity and death.¹ A clinical diagnosis of IPF is made only after careful interpretation of integrated clinical, radiologic, and often histopathologic data.

See related article

Interstitial lung disease encompasses a broad spectrum of parenchymal lung diseases, and a classification of IPF is restricted to a lung injury pattern of usual interstitial pneumonia (UIP) based on high-resolution computed tomography or surgical lung biopsy, after all known causes of UIP have been excluded.¹

However, a lung injury pattern of UIP is not synonymous with IPF, as UIP can be seen with connective tissue disease, chronic hypersensitivity pneumonitis, drug toxicity, and sarcoidosis.¹ As such, rendering a diagnosis of IPF requires a thorough evaluation to exclude such diverse potential etiologies.

In this issue of the Cleveland Clinic Journal of Medicine, Tolle and colleagues² provide an up-to-date, broad overview of IPF focused on what the primary care provider needs to know about the disease. Their review is timely and serves as a useful primer for the practicing clinician.

The field of IPF is actively evolving, as this era has been witness to a recent paradigm shift in pharmacologic management. Immunosuppression is no longer recommended³ and may even be harmful.⁴ And the US Food and Drug Administration has approved 2 antifibrotic drugs—pirfenidone and nintedanib—that have been shown to delay progression of IPF.^5,6

Primary care providers have a unique opportunity to play an integral role in the evaluation and care of patients with IPF, in particular with earlier disease recognition, initial disease assessment, and timely specialty consultative referral—as well as implementing a comprehensive longitudinal care plan.

EARLIER DISEASE RECOGNITION

IPF is a rare disease primarily affecting men over the age of 65.¹ It is reasonable to presume that many or most of these individuals ultimately diagnosed with IPF are already seeking routine care for existing common medical conditions such as hypertension or dyslipidemia—or at least having periodic routine health maintenance assessments. Such evaluations may offer an opportunity for earlier recognition of an underlying fibrotic lung disease that may be subclinical in nature.

IPF has a lower-lung zone predominance. The importance of chest auscultation, particularly listening carefully to the lung bases, is poignantly highlighted in a recent editorial: “It is time that the stethoscope draped around the neck of physicians, which tends to be used for identification purposes rather than for medical diagnosis, be also the (presently only) genuine tool for an earlier diagnosis of IPF.”⁷

Advances in imaging also provide an opportunity for earlier diagnosis. Many patients undergo screening computed tomography for coronary calcium scoring or lung cancer surveillance, and these studies may incidentally identify subtle interstitial lung abnormalities. These incidental findings should lead to further investigation, as they have been shown to be functionally important and carry risk of progression to clinical interstitial lung disease.⁸

But whether evidence of interstitial lung disease is detected incidentally or during testing for respiratory symptoms, further evaluation is necessary. Primary care providers are uniquely positioned to initiate the assessment and to expedite and guide further evaluation and specialty referral consultation to ensure an accurate diagnosis. They can also help grade the severity of the disease with pulmonary function testing, oxygen assessments at rest and with ambulation, and ordering thoracic high-resolution computed tomography to provide valuable information about disease extent and interstitial lung disease pattern.

General practitioners may assess for features suggesting connective tissue disease that would warrant specific serologic testing and dedicated rheumatologic consultation.

Finally, given the rarity, complexity, and challenges of interstitial lung disease, an effective multidisciplinary team consisting of clinicians, radiologists, and pathologists enhances diagnostic accuracy.⁹ This may also help general practitioners deviate from normal patterns of referral to general pulmonary providers, and instead refer patients to specialized centers with dedicated clinical and research expertise in interstitial lung disease.

IMPLEMENTING A COMPREHENSIVE, LONGITUDINAL CARE PLAN

The primary care practitioner often has developed long-term relationships with patients ultimately diagnosed with IPF, and because of this is particularly well positioned to help implement a collaborative and comprehensive care plan. Logistical realities such as distance to a specialty center, limited insurance coverage for specialty visits, and limited specialty availability all reinforce the central role that primary care practitioners play in ensuring that patients adhere to a comprehensive treatment program.

Primary providers may be very experienced and more inclined to manage a number of the common and often important comorbid conditions seen in patients with IPF, such as gastroesophageal reflux disease, obstructive sleep apnea, and depression. Reinforcing to the patient the need to adhere to adjunctive therapies such as supplemental oxygen and pulmonary rehabilitation is another key opportunity to actively engage in the management of patients with IPF.

Primary providers may also play a central role in IPF care through prevention strategies such as smoking cessation and ensuring appropriate immunization against seasonal influenza, pneumococcal pneumonia, and pertussis, among other age-appropriate vaccinations.

With the introduction and expansion of use of nintedanib and pirfenidone for IPF over the past few years, general practitioners may be called on to help manage common gastrointestinal side effects associated with pirfenidone (primarily nausea) and nintedanib (primarily diarrhea), and to be aware of potential drug-drug interactions and other medication-related toxicities.

Finally, as IPF remains a progressive disease, primary care practitioners are often well positioned to help implement palliative care, hospice care, and end-of-life care.

Despite recent advances in treatment, IPF remains a devastating lung disease with a high degree of morbidity and mortality. It takes a village to help care for the IPF patient. And as key members of the healthcare team, primary care providers have unique and important opportunities to help in the early recognition, thorough assessment, and comprehensive management of patients with IPF.

Idiopathic pulmonary fibrosis (IPF) is a devastating progressive fibrosing interstitial lung disease associated with a high burden of morbidity and death.¹ A clinical diagnosis of IPF is made only after careful interpretation of integrated clinical, radiologic, and often histopathologic data.

See related article

Interstitial lung disease encompasses a broad spectrum of parenchymal lung diseases, and a classification of IPF is restricted to a lung injury pattern of usual interstitial pneumonia (UIP) based on high-resolution computed tomography or surgical lung biopsy, after all known causes of UIP have been excluded.¹

However, a lung injury pattern of UIP is not synonymous with IPF, as UIP can be seen with connective tissue disease, chronic hypersensitivity pneumonitis, drug toxicity, and sarcoidosis.¹ As such, rendering a diagnosis of IPF requires a thorough evaluation to exclude such diverse potential etiologies.

In this issue of the Cleveland Clinic Journal of Medicine, Tolle and colleagues² provide an up-to-date, broad overview of IPF focused on what the primary care provider needs to know about the disease. Their review is timely and serves as a useful primer for the practicing clinician.

The field of IPF is actively evolving, as this era has been witness to a recent paradigm shift in pharmacologic management. Immunosuppression is no longer recommended³ and may even be harmful.⁴ And the US Food and Drug Administration has approved 2 antifibrotic drugs—pirfenidone and nintedanib—that have been shown to delay progression of IPF.^5,6

Primary care providers have a unique opportunity to play an integral role in the evaluation and care of patients with IPF, in particular with earlier disease recognition, initial disease assessment, and timely specialty consultative referral—as well as implementing a comprehensive longitudinal care plan.

EARLIER DISEASE RECOGNITION

IPF is a rare disease primarily affecting men over the age of 65.¹ It is reasonable to presume that many or most of these individuals ultimately diagnosed with IPF are already seeking routine care for existing common medical conditions such as hypertension or dyslipidemia—or at least having periodic routine health maintenance assessments. Such evaluations may offer an opportunity for earlier recognition of an underlying fibrotic lung disease that may be subclinical in nature.

IPF has a lower-lung zone predominance. The importance of chest auscultation, particularly listening carefully to the lung bases, is poignantly highlighted in a recent editorial: “It is time that the stethoscope draped around the neck of physicians, which tends to be used for identification purposes rather than for medical diagnosis, be also the (presently only) genuine tool for an earlier diagnosis of IPF.”⁷

Advances in imaging also provide an opportunity for earlier diagnosis. Many patients undergo screening computed tomography for coronary calcium scoring or lung cancer surveillance, and these studies may incidentally identify subtle interstitial lung abnormalities. These incidental findings should lead to further investigation, as they have been shown to be functionally important and carry risk of progression to clinical interstitial lung disease.⁸

But whether evidence of interstitial lung disease is detected incidentally or during testing for respiratory symptoms, further evaluation is necessary. Primary care providers are uniquely positioned to initiate the assessment and to expedite and guide further evaluation and specialty referral consultation to ensure an accurate diagnosis. They can also help grade the severity of the disease with pulmonary function testing, oxygen assessments at rest and with ambulation, and ordering thoracic high-resolution computed tomography to provide valuable information about disease extent and interstitial lung disease pattern.

General practitioners may assess for features suggesting connective tissue disease that would warrant specific serologic testing and dedicated rheumatologic consultation.

Finally, given the rarity, complexity, and challenges of interstitial lung disease, an effective multidisciplinary team consisting of clinicians, radiologists, and pathologists enhances diagnostic accuracy.⁹ This may also help general practitioners deviate from normal patterns of referral to general pulmonary providers, and instead refer patients to specialized centers with dedicated clinical and research expertise in interstitial lung disease.

IMPLEMENTING A COMPREHENSIVE, LONGITUDINAL CARE PLAN

The primary care practitioner often has developed long-term relationships with patients ultimately diagnosed with IPF, and because of this is particularly well positioned to help implement a collaborative and comprehensive care plan. Logistical realities such as distance to a specialty center, limited insurance coverage for specialty visits, and limited specialty availability all reinforce the central role that primary care practitioners play in ensuring that patients adhere to a comprehensive treatment program.

Primary providers may be very experienced and more inclined to manage a number of the common and often important comorbid conditions seen in patients with IPF, such as gastroesophageal reflux disease, obstructive sleep apnea, and depression. Reinforcing to the patient the need to adhere to adjunctive therapies such as supplemental oxygen and pulmonary rehabilitation is another key opportunity to actively engage in the management of patients with IPF.

Primary providers may also play a central role in IPF care through prevention strategies such as smoking cessation and ensuring appropriate immunization against seasonal influenza, pneumococcal pneumonia, and pertussis, among other age-appropriate vaccinations.

With the introduction and expansion of use of nintedanib and pirfenidone for IPF over the past few years, general practitioners may be called on to help manage common gastrointestinal side effects associated with pirfenidone (primarily nausea) and nintedanib (primarily diarrhea), and to be aware of potential drug-drug interactions and other medication-related toxicities.

Finally, as IPF remains a progressive disease, primary care practitioners are often well positioned to help implement palliative care, hospice care, and end-of-life care.

Despite recent advances in treatment, IPF remains a devastating lung disease with a high degree of morbidity and mortality. It takes a village to help care for the IPF patient. And as key members of the healthcare team, primary care providers have unique and important opportunities to help in the early recognition, thorough assessment, and comprehensive management of patients with IPF.

Idiopathic pulmonary fibrosis (IPF) is a devastating progressive fibrosing interstitial lung disease associated with a high burden of morbidity and death.¹ A clinical diagnosis of IPF is made only after careful interpretation of integrated clinical, radiologic, and often histopathologic data.

See related article

Interstitial lung disease encompasses a broad spectrum of parenchymal lung diseases, and a classification of IPF is restricted to a lung injury pattern of usual interstitial pneumonia (UIP) based on high-resolution computed tomography or surgical lung biopsy, after all known causes of UIP have been excluded.¹

However, a lung injury pattern of UIP is not synonymous with IPF, as UIP can be seen with connective tissue disease, chronic hypersensitivity pneumonitis, drug toxicity, and sarcoidosis.¹ As such, rendering a diagnosis of IPF requires a thorough evaluation to exclude such diverse potential etiologies.

In this issue of the Cleveland Clinic Journal of Medicine, Tolle and colleagues² provide an up-to-date, broad overview of IPF focused on what the primary care provider needs to know about the disease. Their review is timely and serves as a useful primer for the practicing clinician.

The field of IPF is actively evolving, as this era has been witness to a recent paradigm shift in pharmacologic management. Immunosuppression is no longer recommended³ and may even be harmful.⁴ And the US Food and Drug Administration has approved 2 antifibrotic drugs—pirfenidone and nintedanib—that have been shown to delay progression of IPF.^5,6

Primary care providers have a unique opportunity to play an integral role in the evaluation and care of patients with IPF, in particular with earlier disease recognition, initial disease assessment, and timely specialty consultative referral—as well as implementing a comprehensive longitudinal care plan.

EARLIER DISEASE RECOGNITION

IPF is a rare disease primarily affecting men over the age of 65.¹ It is reasonable to presume that many or most of these individuals ultimately diagnosed with IPF are already seeking routine care for existing common medical conditions such as hypertension or dyslipidemia—or at least having periodic routine health maintenance assessments. Such evaluations may offer an opportunity for earlier recognition of an underlying fibrotic lung disease that may be subclinical in nature.

IPF has a lower-lung zone predominance. The importance of chest auscultation, particularly listening carefully to the lung bases, is poignantly highlighted in a recent editorial: “It is time that the stethoscope draped around the neck of physicians, which tends to be used for identification purposes rather than for medical diagnosis, be also the (presently only) genuine tool for an earlier diagnosis of IPF.”⁷

Advances in imaging also provide an opportunity for earlier diagnosis. Many patients undergo screening computed tomography for coronary calcium scoring or lung cancer surveillance, and these studies may incidentally identify subtle interstitial lung abnormalities. These incidental findings should lead to further investigation, as they have been shown to be functionally important and carry risk of progression to clinical interstitial lung disease.⁸

But whether evidence of interstitial lung disease is detected incidentally or during testing for respiratory symptoms, further evaluation is necessary. Primary care providers are uniquely positioned to initiate the assessment and to expedite and guide further evaluation and specialty referral consultation to ensure an accurate diagnosis. They can also help grade the severity of the disease with pulmonary function testing, oxygen assessments at rest and with ambulation, and ordering thoracic high-resolution computed tomography to provide valuable information about disease extent and interstitial lung disease pattern.

General practitioners may assess for features suggesting connective tissue disease that would warrant specific serologic testing and dedicated rheumatologic consultation.

Finally, given the rarity, complexity, and challenges of interstitial lung disease, an effective multidisciplinary team consisting of clinicians, radiologists, and pathologists enhances diagnostic accuracy.⁹ This may also help general practitioners deviate from normal patterns of referral to general pulmonary providers, and instead refer patients to specialized centers with dedicated clinical and research expertise in interstitial lung disease.

IMPLEMENTING A COMPREHENSIVE, LONGITUDINAL CARE PLAN

The primary care practitioner often has developed long-term relationships with patients ultimately diagnosed with IPF, and because of this is particularly well positioned to help implement a collaborative and comprehensive care plan. Logistical realities such as distance to a specialty center, limited insurance coverage for specialty visits, and limited specialty availability all reinforce the central role that primary care practitioners play in ensuring that patients adhere to a comprehensive treatment program.

Primary providers may be very experienced and more inclined to manage a number of the common and often important comorbid conditions seen in patients with IPF, such as gastroesophageal reflux disease, obstructive sleep apnea, and depression. Reinforcing to the patient the need to adhere to adjunctive therapies such as supplemental oxygen and pulmonary rehabilitation is another key opportunity to actively engage in the management of patients with IPF.

Primary providers may also play a central role in IPF care through prevention strategies such as smoking cessation and ensuring appropriate immunization against seasonal influenza, pneumococcal pneumonia, and pertussis, among other age-appropriate vaccinations.

With the introduction and expansion of use of nintedanib and pirfenidone for IPF over the past few years, general practitioners may be called on to help manage common gastrointestinal side effects associated with pirfenidone (primarily nausea) and nintedanib (primarily diarrhea), and to be aware of potential drug-drug interactions and other medication-related toxicities.

Finally, as IPF remains a progressive disease, primary care practitioners are often well positioned to help implement palliative care, hospice care, and end-of-life care.

Despite recent advances in treatment, IPF remains a devastating lung disease with a high degree of morbidity and mortality. It takes a village to help care for the IPF patient. And as key members of the healthcare team, primary care providers have unique and important opportunities to help in the early recognition, thorough assessment, and comprehensive management of patients with IPF.

A 45-year-old man with end-stage renal disease secondary to hypertension presented with abdominal pain, nausea, vomiting, and fever. He had been on peritoneal dialysis for 15 years.

Results of initial laboratory testing were as follows:

• Sodium 137 mmol/L (reference range 136–144)
• Potassium 3.7 mmol/L (3.5–5.0)
• Bicarbonate 31 mmol/L (22–30)
• Creatinine 17.5 mg/dL (0.58–0.96)
• Blood urea nitrogen 57 mg/dL (7–21)
• Lactic acid 1.7 mmol/L (0.5–2.2)
• White blood cell count 14.34 × 10⁹/L (3.70–11.0).

Blood cultures were negative. Peritoneal fluid analysis showed a white blood cell count of 1.2 × 10⁹/L (reference range < 0.5 × 10⁹/L) with 89% neutrophils, and an amylase level less than 3 U/L (reference range < 100). Fluid cultures were positive for coagulase-negative staphylococci and Staphylococcus epidermidis.

CAUSES AND CLINICAL FEATURES

Encapsulating peritoneal sclerosis is a devastating complication of peritoneal dialysis, occurring in 3% of patients on peritoneal dialysis. The mortality rate is above 40%.^1,2 It is characterized by an initial inflammatory phase followed by extensive intraperitoneal fibrosis and encasement of bowel. Causes include prolonged exposure to peritoneal dialysis or glucose degradation products, a history of severe peritonitis, use of acetate as a dialysate buffer, and reaction to medications such as beta-blockers.³

Clinical features result from inflammation, ileus, and peritoneal adhesions and include abdominal pain, nausea, and vomiting. A high peritoneal transport rate, which often heralds development of encapsulating peritoneal sclerosis, leads to failure of ultrafiltration and to fluid retention.

CT is recommended for diagnosis and demonstrates peritoneal calcification with bowel thickening and dilation.

TREATMENT

Treatment entails stopping peritoneal dialysis, changing to hemodialysis, bowel rest, and corticosteroids. Successful treatment has been reported with a combination of corticosteroids and azathioprine.^4,5 A retrospective study showed that adding the antifibrotic agent tamoxifen was associated with a decrease in the mortality rate.⁶ Bowel obstruction is a common complication, and surgery may be indicated. Enterolysis is a new surgical technique that has shown improved outcomes.⁷         

A 45-year-old man with end-stage renal disease secondary to hypertension presented with abdominal pain, nausea, vomiting, and fever. He had been on peritoneal dialysis for 15 years.

Results of initial laboratory testing were as follows:

• Sodium 137 mmol/L (reference range 136–144)
• Potassium 3.7 mmol/L (3.5–5.0)
• Bicarbonate 31 mmol/L (22–30)
• Creatinine 17.5 mg/dL (0.58–0.96)
• Blood urea nitrogen 57 mg/dL (7–21)
• Lactic acid 1.7 mmol/L (0.5–2.2)
• White blood cell count 14.34 × 10⁹/L (3.70–11.0).

Blood cultures were negative. Peritoneal fluid analysis showed a white blood cell count of 1.2 × 10⁹/L (reference range < 0.5 × 10⁹/L) with 89% neutrophils, and an amylase level less than 3 U/L (reference range < 100). Fluid cultures were positive for coagulase-negative staphylococci and Staphylococcus epidermidis.

CAUSES AND CLINICAL FEATURES

Encapsulating peritoneal sclerosis is a devastating complication of peritoneal dialysis, occurring in 3% of patients on peritoneal dialysis. The mortality rate is above 40%.^1,2 It is characterized by an initial inflammatory phase followed by extensive intraperitoneal fibrosis and encasement of bowel. Causes include prolonged exposure to peritoneal dialysis or glucose degradation products, a history of severe peritonitis, use of acetate as a dialysate buffer, and reaction to medications such as beta-blockers.³

Clinical features result from inflammation, ileus, and peritoneal adhesions and include abdominal pain, nausea, and vomiting. A high peritoneal transport rate, which often heralds development of encapsulating peritoneal sclerosis, leads to failure of ultrafiltration and to fluid retention.

CT is recommended for diagnosis and demonstrates peritoneal calcification with bowel thickening and dilation.

TREATMENT

Treatment entails stopping peritoneal dialysis, changing to hemodialysis, bowel rest, and corticosteroids. Successful treatment has been reported with a combination of corticosteroids and azathioprine.^4,5 A retrospective study showed that adding the antifibrotic agent tamoxifen was associated with a decrease in the mortality rate.⁶ Bowel obstruction is a common complication, and surgery may be indicated. Enterolysis is a new surgical technique that has shown improved outcomes.⁷         

A 45-year-old man with end-stage renal disease secondary to hypertension presented with abdominal pain, nausea, vomiting, and fever. He had been on peritoneal dialysis for 15 years.

Results of initial laboratory testing were as follows:

• Sodium 137 mmol/L (reference range 136–144)
• Potassium 3.7 mmol/L (3.5–5.0)
• Bicarbonate 31 mmol/L (22–30)
• Creatinine 17.5 mg/dL (0.58–0.96)
• Blood urea nitrogen 57 mg/dL (7–21)
• Lactic acid 1.7 mmol/L (0.5–2.2)
• White blood cell count 14.34 × 10⁹/L (3.70–11.0).

Blood cultures were negative. Peritoneal fluid analysis showed a white blood cell count of 1.2 × 10⁹/L (reference range < 0.5 × 10⁹/L) with 89% neutrophils, and an amylase level less than 3 U/L (reference range < 100). Fluid cultures were positive for coagulase-negative staphylococci and Staphylococcus epidermidis.

CAUSES AND CLINICAL FEATURES

Encapsulating peritoneal sclerosis is a devastating complication of peritoneal dialysis, occurring in 3% of patients on peritoneal dialysis. The mortality rate is above 40%.^1,2 It is characterized by an initial inflammatory phase followed by extensive intraperitoneal fibrosis and encasement of bowel. Causes include prolonged exposure to peritoneal dialysis or glucose degradation products, a history of severe peritonitis, use of acetate as a dialysate buffer, and reaction to medications such as beta-blockers.³

Clinical features result from inflammation, ileus, and peritoneal adhesions and include abdominal pain, nausea, and vomiting. A high peritoneal transport rate, which often heralds development of encapsulating peritoneal sclerosis, leads to failure of ultrafiltration and to fluid retention.

CT is recommended for diagnosis and demonstrates peritoneal calcification with bowel thickening and dilation.

TREATMENT

Treatment entails stopping peritoneal dialysis, changing to hemodialysis, bowel rest, and corticosteroids. Successful treatment has been reported with a combination of corticosteroids and azathioprine.^4,5 A retrospective study showed that adding the antifibrotic agent tamoxifen was associated with a decrease in the mortality rate.⁶ Bowel obstruction is a common complication, and surgery may be indicated. Enterolysis is a new surgical technique that has shown improved outcomes.⁷         

ABSTRACT

The objective of this study is to determine the reproducibility and feasibility of using 3-dimensional (3-D) computer simulation of proximal humerus fracture computed tomography (CT) scans for fracture reduction. We hypothesized that anatomic reconstruction with 3-D models would be anatomically accurate and reproducible.

Preoperative CT scans of 28 patients with 3- and 4-part (AO classification 11-B1, 11-B2, 11-C1, 11-C2) proximal humerus fractures who were treated by hemiarthroplasty were converted into 3-D computer models. The displaced fractured fragments were anatomically reduced with computer simulation by 2 fellowship-trained shoulder surgeons, and measurements were made of the reconstructed proximal humerus.

The measurements of the reconstructed models had very good to excellent interobserver and intraobserver reliability. The reconstructions of these humerus fractures showed interclass correlation coefficients ranging from 0.71 to 0.93 between 1 observer and from 0.82 to 0.98 between 2 different observers. The fracture reduction was judged against normal proximal humerus geometry to determine reduction accuracy.

The 3-D modeling techniques used to reconstruct 3- and 4-part proximal humerus fractures were reliable and accurate. This technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of open reduction and internal fixation or hemiarthroplasty for 3- and 4-part proximal humerus fractures.

The treatment of proximal humerus fractures is influenced by multiple factors, including patient age, associated injuries, bone quality, and fracture pattern. Three- and 4-part fractures are among the more severe of these fractures, which may result in vascular compromise to the humeral head, leading to avascular necrosis. Surgical goals for the management of these fractures are to optimize functional outcomes by re-creating a stable construct with a functional rotator cuff by open reduction and internal fixation (ORIF), hemiarthroplasty with tuberosity ORIF, or reverse shoulder replacement. Achieving a good outcome following hemiarthroplasty is dependent on many factors, including anatomic tuberosity healing and component positioning.^1,2,3 Repairing the greater tuberosity in a near-anatomic position has been shown to greatly affect the results of hemiarthroplasty for fracture.^3,4

Continue to: Three-dimensional (3-D) modeling...

METHODS

After Institutional Review Board approval was obtained, we reviewed the medical records of consecutive patients with a diagnosis of proximal humeral fracture and the treatment codes for hemiarthroplasty from 2000 to 2013. Inclusion criteria included 3- and 4-part fractures (AO classifications 11-B1, 11-B2, 11-C1, 11-C2). CT scans with insufficient quality to differentiate bone from soft tissue (inadequate signal-to-noise ratio) were excluded from the study. A total of 28 patients with adequate CT scans met the criteria for inclusion in this study.

The CT scan protocol included 0.5-mm axial cuts with inclusion of the proximal humerus in the Digital Imaging and Communications in Medicine format. These CT scans were converted into patient-specific 3-D computer models of the shoulder using Mimics software (Materialise Inc.). The use of this software to produce anatomically accurate models has previously been verified in a shoulder model.^6,7 The tuberosity fragments were then individually separated from each other using the voxel-selecting capabilities of 3-D software and manipulated with translation and rotation for anatomic reduction (Figures 1A-1D, Figure 2).

The de-identified anatomically reconstructed shoulder models were then uploaded into Materialise’s Magics rapid prototyping software, and a user-defined humeral Cartesian coordinate system was defined with anatomic landmarks as reference points to standardize the position of each model (Figure 3).^8,9 

A series of measurements were made on these models to assess the validity and reliability of the reassembly. The bicipital groove at the anatomic neck was used to measure humeral head version as described by Kummer and colleagues.¹⁰ The head-shaft angle, humeral head-greater tuberosity distance, humeral head-bicipital groove angle, and posterior and medial humeral head offset were measured directly on the reconstructed humerus.

Continue to: Two fellowship-trained shoulder...

STATISTICS

The measured dimensions of the 28 reassembled proximal humeri models were averaged across all trials between the 2 fellowship-trained surgeons and compared with the range of normal dimensions of a healthy proximal humerus using the 2 one-sided tests (TOST) method for equivalence between 2 means given a range. The interobserver and intraobserver reliabilities were quantified using the interclass correlation coefficient. An excellent correlation was defined as a correlation coefficient >0.81; very good was defined as 0.61 to 0.80; and good was defined as 0.41 to 0.60.

RESULTS

Of the patients studied, 9 (32.1%) were male, and the average age at the time of CT scanning was 72 years. Of the 28 patients with fracture, 18 (64.2%) had 3-part fractures (AO classifications 11-B1, 11-B2), and 10 (35.8%) had 4-part fractures (AO classifications 11-C1, 11-C2). When examining the location of the intertubercular fracture line, we found that 13 (46.4%) fractures went through the bicipital groove. Of the remaining fracture lines, 9 (32.1%) extended into the greater tuberosity and 6 (21.4%) extended into the lesser tuberosity.

All users were able to reconstruct all 28 fractures using this technique. The average measured dimensions fell within the range of dimensions of a normal healthy proximal humerus specified in the literature to within a 95% confidence interval using the TOST for equivalence, in which we compared measured values with ranges reported in the literature (Table).^11,12,13 

Table. Dimensions of Proximal Humerus Geometry

The reconstructions of these humerus fractures showed intraclass correlation coefficients ranging from 0.71 to 0.93 in 1 observer and interclass correlation coefficients from 0.82 to 0.98 between 2 different observers (Table).

DISCUSSION

This study demonstrates that it is feasible to reliably and accurately reconstruct the original anatomy of the proximal humerus by using 3-D computer modeling of proximal humerus fractures. Poor outcomes after hemiarthroplasty for proximal humerus fractures are mostly related to tuberosity malpositioning, resorption, or failure of fixation and resultant dysfunction of the rotator cuff.^14,15,16 These studies highlight the importance of accurate tuberosity reduction during surgical care of these fractures.

Continue to: The 3-D computer model...

Overreduction of greater tuberosity to create cortical overlap with the lateral shaft may be used to promote bony union. As a result of this distalization, there may be extra strains placed on the rotator cuff, making the patient more prone to rotator cuff tear, as well as improperly balancing the dynamic stabilizers of the shoulder. Poor clinical outcomes in hemiarthroplasty for proximal humerus fractures have been correlated with a greater tuberosity placed distal relative to the humeral head by 1 cm in a study² and by 2 cm in another.³

This study has several limitations. The first is the assumption that our injured patients had preinjury proximal humerus geometry within the range of normal dimensions of a healthy humerus. Unfortunately, because we were unable to obtain CT scans of the contralateral shoulder, we had to use standard proximal humerus geometry as the control. Another limitation, inherent in the technique, is that only cortical and dense trabecular bone was modeled, so that comminuted or osteoporotic bone was not well modeled. This study did not correlate the findings from these models with clinical outcomes. A prospective study is needed to evaluate the impact of this 3-D modeling on fracture reductions and clinical outcomes.

This study demonstrates that patient-specific modeling of proximal humerus fracture 3-D CT scans may help surgeons reliably and accurately reconstruct fractures. This technique may have utility in the preoperative planning of tuberosity fracture reduction and hemiarthroplasty. It gives surgeons the ability to visualize fracture fragments, and the process of reconstructing the fragments may help surgeons understand the required maneuvers for reduction at the time of surgery. This technique also provides dimensions of the patient’s native humerus, thus potentially improving the anatomic accuracy of the reduction or hemiarthroplasty reconstruction. With the new trend toward patient-specific instrumentation, this study also provides a means of planning the size of the humeral prostheses as well as the version relative to the biceps groove and intertubercular fracture line.

CONCLUSION

This study demonstrates the feasibility of using 3-D computer modeling of complex proximal humerus fractures in anatomic reconstruction. These techniques of computer-simulated 3-D models are valid and reliable. We believe that this technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of hemiarthroplasty for 3- and 4-part proximal humerus fractures by providing improved understanding of the patient’s native humeral geometry and tuberosity reduction.

ABSTRACT

The objective of this study is to determine the reproducibility and feasibility of using 3-dimensional (3-D) computer simulation of proximal humerus fracture computed tomography (CT) scans for fracture reduction. We hypothesized that anatomic reconstruction with 3-D models would be anatomically accurate and reproducible.

Preoperative CT scans of 28 patients with 3- and 4-part (AO classification 11-B1, 11-B2, 11-C1, 11-C2) proximal humerus fractures who were treated by hemiarthroplasty were converted into 3-D computer models. The displaced fractured fragments were anatomically reduced with computer simulation by 2 fellowship-trained shoulder surgeons, and measurements were made of the reconstructed proximal humerus.

The measurements of the reconstructed models had very good to excellent interobserver and intraobserver reliability. The reconstructions of these humerus fractures showed interclass correlation coefficients ranging from 0.71 to 0.93 between 1 observer and from 0.82 to 0.98 between 2 different observers. The fracture reduction was judged against normal proximal humerus geometry to determine reduction accuracy.

The 3-D modeling techniques used to reconstruct 3- and 4-part proximal humerus fractures were reliable and accurate. This technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of open reduction and internal fixation or hemiarthroplasty for 3- and 4-part proximal humerus fractures.

The treatment of proximal humerus fractures is influenced by multiple factors, including patient age, associated injuries, bone quality, and fracture pattern. Three- and 4-part fractures are among the more severe of these fractures, which may result in vascular compromise to the humeral head, leading to avascular necrosis. Surgical goals for the management of these fractures are to optimize functional outcomes by re-creating a stable construct with a functional rotator cuff by open reduction and internal fixation (ORIF), hemiarthroplasty with tuberosity ORIF, or reverse shoulder replacement. Achieving a good outcome following hemiarthroplasty is dependent on many factors, including anatomic tuberosity healing and component positioning.^1,2,3 Repairing the greater tuberosity in a near-anatomic position has been shown to greatly affect the results of hemiarthroplasty for fracture.^3,4

Continue to: Three-dimensional (3-D) modeling...

METHODS

After Institutional Review Board approval was obtained, we reviewed the medical records of consecutive patients with a diagnosis of proximal humeral fracture and the treatment codes for hemiarthroplasty from 2000 to 2013. Inclusion criteria included 3- and 4-part fractures (AO classifications 11-B1, 11-B2, 11-C1, 11-C2). CT scans with insufficient quality to differentiate bone from soft tissue (inadequate signal-to-noise ratio) were excluded from the study. A total of 28 patients with adequate CT scans met the criteria for inclusion in this study.

The CT scan protocol included 0.5-mm axial cuts with inclusion of the proximal humerus in the Digital Imaging and Communications in Medicine format. These CT scans were converted into patient-specific 3-D computer models of the shoulder using Mimics software (Materialise Inc.). The use of this software to produce anatomically accurate models has previously been verified in a shoulder model.^6,7 The tuberosity fragments were then individually separated from each other using the voxel-selecting capabilities of 3-D software and manipulated with translation and rotation for anatomic reduction (Figures 1A-1D, Figure 2).

The de-identified anatomically reconstructed shoulder models were then uploaded into Materialise’s Magics rapid prototyping software, and a user-defined humeral Cartesian coordinate system was defined with anatomic landmarks as reference points to standardize the position of each model (Figure 3).^8,9 

A series of measurements were made on these models to assess the validity and reliability of the reassembly. The bicipital groove at the anatomic neck was used to measure humeral head version as described by Kummer and colleagues.¹⁰ The head-shaft angle, humeral head-greater tuberosity distance, humeral head-bicipital groove angle, and posterior and medial humeral head offset were measured directly on the reconstructed humerus.

Continue to: Two fellowship-trained shoulder...

STATISTICS

The measured dimensions of the 28 reassembled proximal humeri models were averaged across all trials between the 2 fellowship-trained surgeons and compared with the range of normal dimensions of a healthy proximal humerus using the 2 one-sided tests (TOST) method for equivalence between 2 means given a range. The interobserver and intraobserver reliabilities were quantified using the interclass correlation coefficient. An excellent correlation was defined as a correlation coefficient >0.81; very good was defined as 0.61 to 0.80; and good was defined as 0.41 to 0.60.

RESULTS

Of the patients studied, 9 (32.1%) were male, and the average age at the time of CT scanning was 72 years. Of the 28 patients with fracture, 18 (64.2%) had 3-part fractures (AO classifications 11-B1, 11-B2), and 10 (35.8%) had 4-part fractures (AO classifications 11-C1, 11-C2). When examining the location of the intertubercular fracture line, we found that 13 (46.4%) fractures went through the bicipital groove. Of the remaining fracture lines, 9 (32.1%) extended into the greater tuberosity and 6 (21.4%) extended into the lesser tuberosity.

All users were able to reconstruct all 28 fractures using this technique. The average measured dimensions fell within the range of dimensions of a normal healthy proximal humerus specified in the literature to within a 95% confidence interval using the TOST for equivalence, in which we compared measured values with ranges reported in the literature (Table).^11,12,13 

Table. Dimensions of Proximal Humerus Geometry

The reconstructions of these humerus fractures showed intraclass correlation coefficients ranging from 0.71 to 0.93 in 1 observer and interclass correlation coefficients from 0.82 to 0.98 between 2 different observers (Table).

DISCUSSION

This study demonstrates that it is feasible to reliably and accurately reconstruct the original anatomy of the proximal humerus by using 3-D computer modeling of proximal humerus fractures. Poor outcomes after hemiarthroplasty for proximal humerus fractures are mostly related to tuberosity malpositioning, resorption, or failure of fixation and resultant dysfunction of the rotator cuff.^14,15,16 These studies highlight the importance of accurate tuberosity reduction during surgical care of these fractures.

Continue to: The 3-D computer model...

Overreduction of greater tuberosity to create cortical overlap with the lateral shaft may be used to promote bony union. As a result of this distalization, there may be extra strains placed on the rotator cuff, making the patient more prone to rotator cuff tear, as well as improperly balancing the dynamic stabilizers of the shoulder. Poor clinical outcomes in hemiarthroplasty for proximal humerus fractures have been correlated with a greater tuberosity placed distal relative to the humeral head by 1 cm in a study² and by 2 cm in another.³

This study has several limitations. The first is the assumption that our injured patients had preinjury proximal humerus geometry within the range of normal dimensions of a healthy humerus. Unfortunately, because we were unable to obtain CT scans of the contralateral shoulder, we had to use standard proximal humerus geometry as the control. Another limitation, inherent in the technique, is that only cortical and dense trabecular bone was modeled, so that comminuted or osteoporotic bone was not well modeled. This study did not correlate the findings from these models with clinical outcomes. A prospective study is needed to evaluate the impact of this 3-D modeling on fracture reductions and clinical outcomes.

This study demonstrates that patient-specific modeling of proximal humerus fracture 3-D CT scans may help surgeons reliably and accurately reconstruct fractures. This technique may have utility in the preoperative planning of tuberosity fracture reduction and hemiarthroplasty. It gives surgeons the ability to visualize fracture fragments, and the process of reconstructing the fragments may help surgeons understand the required maneuvers for reduction at the time of surgery. This technique also provides dimensions of the patient’s native humerus, thus potentially improving the anatomic accuracy of the reduction or hemiarthroplasty reconstruction. With the new trend toward patient-specific instrumentation, this study also provides a means of planning the size of the humeral prostheses as well as the version relative to the biceps groove and intertubercular fracture line.

CONCLUSION

This study demonstrates the feasibility of using 3-D computer modeling of complex proximal humerus fractures in anatomic reconstruction. These techniques of computer-simulated 3-D models are valid and reliable. We believe that this technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of hemiarthroplasty for 3- and 4-part proximal humerus fractures by providing improved understanding of the patient’s native humeral geometry and tuberosity reduction.

ABSTRACT

The objective of this study is to determine the reproducibility and feasibility of using 3-dimensional (3-D) computer simulation of proximal humerus fracture computed tomography (CT) scans for fracture reduction. We hypothesized that anatomic reconstruction with 3-D models would be anatomically accurate and reproducible.

Preoperative CT scans of 28 patients with 3- and 4-part (AO classification 11-B1, 11-B2, 11-C1, 11-C2) proximal humerus fractures who were treated by hemiarthroplasty were converted into 3-D computer models. The displaced fractured fragments were anatomically reduced with computer simulation by 2 fellowship-trained shoulder surgeons, and measurements were made of the reconstructed proximal humerus.

The measurements of the reconstructed models had very good to excellent interobserver and intraobserver reliability. The reconstructions of these humerus fractures showed interclass correlation coefficients ranging from 0.71 to 0.93 between 1 observer and from 0.82 to 0.98 between 2 different observers. The fracture reduction was judged against normal proximal humerus geometry to determine reduction accuracy.

The 3-D modeling techniques used to reconstruct 3- and 4-part proximal humerus fractures were reliable and accurate. This technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of open reduction and internal fixation or hemiarthroplasty for 3- and 4-part proximal humerus fractures.

The treatment of proximal humerus fractures is influenced by multiple factors, including patient age, associated injuries, bone quality, and fracture pattern. Three- and 4-part fractures are among the more severe of these fractures, which may result in vascular compromise to the humeral head, leading to avascular necrosis. Surgical goals for the management of these fractures are to optimize functional outcomes by re-creating a stable construct with a functional rotator cuff by open reduction and internal fixation (ORIF), hemiarthroplasty with tuberosity ORIF, or reverse shoulder replacement. Achieving a good outcome following hemiarthroplasty is dependent on many factors, including anatomic tuberosity healing and component positioning.^1,2,3 Repairing the greater tuberosity in a near-anatomic position has been shown to greatly affect the results of hemiarthroplasty for fracture.^3,4

Continue to: Three-dimensional (3-D) modeling...

METHODS

After Institutional Review Board approval was obtained, we reviewed the medical records of consecutive patients with a diagnosis of proximal humeral fracture and the treatment codes for hemiarthroplasty from 2000 to 2013. Inclusion criteria included 3- and 4-part fractures (AO classifications 11-B1, 11-B2, 11-C1, 11-C2). CT scans with insufficient quality to differentiate bone from soft tissue (inadequate signal-to-noise ratio) were excluded from the study. A total of 28 patients with adequate CT scans met the criteria for inclusion in this study.

The CT scan protocol included 0.5-mm axial cuts with inclusion of the proximal humerus in the Digital Imaging and Communications in Medicine format. These CT scans were converted into patient-specific 3-D computer models of the shoulder using Mimics software (Materialise Inc.). The use of this software to produce anatomically accurate models has previously been verified in a shoulder model.^6,7 The tuberosity fragments were then individually separated from each other using the voxel-selecting capabilities of 3-D software and manipulated with translation and rotation for anatomic reduction (Figures 1A-1D, Figure 2).

The de-identified anatomically reconstructed shoulder models were then uploaded into Materialise’s Magics rapid prototyping software, and a user-defined humeral Cartesian coordinate system was defined with anatomic landmarks as reference points to standardize the position of each model (Figure 3).^8,9 

A series of measurements were made on these models to assess the validity and reliability of the reassembly. The bicipital groove at the anatomic neck was used to measure humeral head version as described by Kummer and colleagues.¹⁰ The head-shaft angle, humeral head-greater tuberosity distance, humeral head-bicipital groove angle, and posterior and medial humeral head offset were measured directly on the reconstructed humerus.

Continue to: Two fellowship-trained shoulder...

STATISTICS

The measured dimensions of the 28 reassembled proximal humeri models were averaged across all trials between the 2 fellowship-trained surgeons and compared with the range of normal dimensions of a healthy proximal humerus using the 2 one-sided tests (TOST) method for equivalence between 2 means given a range. The interobserver and intraobserver reliabilities were quantified using the interclass correlation coefficient. An excellent correlation was defined as a correlation coefficient >0.81; very good was defined as 0.61 to 0.80; and good was defined as 0.41 to 0.60.

RESULTS

Of the patients studied, 9 (32.1%) were male, and the average age at the time of CT scanning was 72 years. Of the 28 patients with fracture, 18 (64.2%) had 3-part fractures (AO classifications 11-B1, 11-B2), and 10 (35.8%) had 4-part fractures (AO classifications 11-C1, 11-C2). When examining the location of the intertubercular fracture line, we found that 13 (46.4%) fractures went through the bicipital groove. Of the remaining fracture lines, 9 (32.1%) extended into the greater tuberosity and 6 (21.4%) extended into the lesser tuberosity.

All users were able to reconstruct all 28 fractures using this technique. The average measured dimensions fell within the range of dimensions of a normal healthy proximal humerus specified in the literature to within a 95% confidence interval using the TOST for equivalence, in which we compared measured values with ranges reported in the literature (Table).^11,12,13 

Table. Dimensions of Proximal Humerus Geometry

The reconstructions of these humerus fractures showed intraclass correlation coefficients ranging from 0.71 to 0.93 in 1 observer and interclass correlation coefficients from 0.82 to 0.98 between 2 different observers (Table).

DISCUSSION

This study demonstrates that it is feasible to reliably and accurately reconstruct the original anatomy of the proximal humerus by using 3-D computer modeling of proximal humerus fractures. Poor outcomes after hemiarthroplasty for proximal humerus fractures are mostly related to tuberosity malpositioning, resorption, or failure of fixation and resultant dysfunction of the rotator cuff.^14,15,16 These studies highlight the importance of accurate tuberosity reduction during surgical care of these fractures.

Continue to: The 3-D computer model...

Overreduction of greater tuberosity to create cortical overlap with the lateral shaft may be used to promote bony union. As a result of this distalization, there may be extra strains placed on the rotator cuff, making the patient more prone to rotator cuff tear, as well as improperly balancing the dynamic stabilizers of the shoulder. Poor clinical outcomes in hemiarthroplasty for proximal humerus fractures have been correlated with a greater tuberosity placed distal relative to the humeral head by 1 cm in a study² and by 2 cm in another.³

This study has several limitations. The first is the assumption that our injured patients had preinjury proximal humerus geometry within the range of normal dimensions of a healthy humerus. Unfortunately, because we were unable to obtain CT scans of the contralateral shoulder, we had to use standard proximal humerus geometry as the control. Another limitation, inherent in the technique, is that only cortical and dense trabecular bone was modeled, so that comminuted or osteoporotic bone was not well modeled. This study did not correlate the findings from these models with clinical outcomes. A prospective study is needed to evaluate the impact of this 3-D modeling on fracture reductions and clinical outcomes.

This study demonstrates that patient-specific modeling of proximal humerus fracture 3-D CT scans may help surgeons reliably and accurately reconstruct fractures. This technique may have utility in the preoperative planning of tuberosity fracture reduction and hemiarthroplasty. It gives surgeons the ability to visualize fracture fragments, and the process of reconstructing the fragments may help surgeons understand the required maneuvers for reduction at the time of surgery. This technique also provides dimensions of the patient’s native humerus, thus potentially improving the anatomic accuracy of the reduction or hemiarthroplasty reconstruction. With the new trend toward patient-specific instrumentation, this study also provides a means of planning the size of the humeral prostheses as well as the version relative to the biceps groove and intertubercular fracture line.

CONCLUSION

This study demonstrates the feasibility of using 3-D computer modeling of complex proximal humerus fractures in anatomic reconstruction. These techniques of computer-simulated 3-D models are valid and reliable. We believe that this technique of modeling and reconstructing proximal humerus fractures could be used to enhance the preoperative planning of hemiarthroplasty for 3- and 4-part proximal humerus fractures by providing improved understanding of the patient’s native humeral geometry and tuberosity reduction.

Background: For many common conditions, expert guidelines such as Choosing Wisely recommend against ordering specific low-value tests, yet overuse of these tests remains widespread, and unnecessary care may account for up to a third of all medical expenditures. Studies have demonstrated that there is considerable geographic variation in health care usage and higher overall imaging among clinicians who own imaging equipment. No prior study has assessed whether prior ordering patterns of low-value care predict future ordering patterns or whether providers who order low-value imaging in one clinical scenario are more likely to do so in another scenario.

Study design: Retrospective analysis of insurance claims data.

Setting: Medical claims data from a large U.S. commercial health insurer, inclusive of 29 million commercially insured members across all 50 states from January 2010 to December 2014.

Synopsis: Using the claims database, researchers created three unique study samples to examine clinician predictors of low-value imaging. The study involved outpatient visits by patients aged 18-64 years without red-flag symptoms. The first included 1,007,392 visits across 878,720 patients with acute, uncomplicated low-back pain. Physicians who ordered imaging for the prior patient with back pain were 1.8 times more likely to do so again. Similarly, in 492,804 visits by 417,010 patients with headache, clinicians who ordered imaging on the prior patient demonstrated a twofold higher odds of imaging. Physicians who practiced low-value ordering for one condition were 1.8 times more likely to do so for the other. Across all studies, imaging ownership was an independent predictor (odds ratio, 1.8).

As this study analyzed only claims data, some patients may have warranted imaging based on red-flag symptoms that were not documented. Hospitalists designing initiatives to reduce low-value testing should consider targeting specific providers with a history of low-value test use.

Bottom line: Among commercially insured patients, a clinician’s prior imaging pattern and ownership of imaging equipment were strong independent predictors of low-value back pain and headache imaging.

Citation: Hong AS et al. Clinician-level predictors for ordering low-value imaging. JAMA Intern Med. 2017 Nov 1;177(11):1577-85.

Background: For many common conditions, expert guidelines such as Choosing Wisely recommend against ordering specific low-value tests, yet overuse of these tests remains widespread, and unnecessary care may account for up to a third of all medical expenditures. Studies have demonstrated that there is considerable geographic variation in health care usage and higher overall imaging among clinicians who own imaging equipment. No prior study has assessed whether prior ordering patterns of low-value care predict future ordering patterns or whether providers who order low-value imaging in one clinical scenario are more likely to do so in another scenario.

Study design: Retrospective analysis of insurance claims data.

Setting: Medical claims data from a large U.S. commercial health insurer, inclusive of 29 million commercially insured members across all 50 states from January 2010 to December 2014.

Synopsis: Using the claims database, researchers created three unique study samples to examine clinician predictors of low-value imaging. The study involved outpatient visits by patients aged 18-64 years without red-flag symptoms. The first included 1,007,392 visits across 878,720 patients with acute, uncomplicated low-back pain. Physicians who ordered imaging for the prior patient with back pain were 1.8 times more likely to do so again. Similarly, in 492,804 visits by 417,010 patients with headache, clinicians who ordered imaging on the prior patient demonstrated a twofold higher odds of imaging. Physicians who practiced low-value ordering for one condition were 1.8 times more likely to do so for the other. Across all studies, imaging ownership was an independent predictor (odds ratio, 1.8).

As this study analyzed only claims data, some patients may have warranted imaging based on red-flag symptoms that were not documented. Hospitalists designing initiatives to reduce low-value testing should consider targeting specific providers with a history of low-value test use.

Bottom line: Among commercially insured patients, a clinician’s prior imaging pattern and ownership of imaging equipment were strong independent predictors of low-value back pain and headache imaging.

Citation: Hong AS et al. Clinician-level predictors for ordering low-value imaging. JAMA Intern Med. 2017 Nov 1;177(11):1577-85.

Background: For many common conditions, expert guidelines such as Choosing Wisely recommend against ordering specific low-value tests, yet overuse of these tests remains widespread, and unnecessary care may account for up to a third of all medical expenditures. Studies have demonstrated that there is considerable geographic variation in health care usage and higher overall imaging among clinicians who own imaging equipment. No prior study has assessed whether prior ordering patterns of low-value care predict future ordering patterns or whether providers who order low-value imaging in one clinical scenario are more likely to do so in another scenario.

Study design: Retrospective analysis of insurance claims data.

Setting: Medical claims data from a large U.S. commercial health insurer, inclusive of 29 million commercially insured members across all 50 states from January 2010 to December 2014.

Synopsis: Using the claims database, researchers created three unique study samples to examine clinician predictors of low-value imaging. The study involved outpatient visits by patients aged 18-64 years without red-flag symptoms. The first included 1,007,392 visits across 878,720 patients with acute, uncomplicated low-back pain. Physicians who ordered imaging for the prior patient with back pain were 1.8 times more likely to do so again. Similarly, in 492,804 visits by 417,010 patients with headache, clinicians who ordered imaging on the prior patient demonstrated a twofold higher odds of imaging. Physicians who practiced low-value ordering for one condition were 1.8 times more likely to do so for the other. Across all studies, imaging ownership was an independent predictor (odds ratio, 1.8).

As this study analyzed only claims data, some patients may have warranted imaging based on red-flag symptoms that were not documented. Hospitalists designing initiatives to reduce low-value testing should consider targeting specific providers with a history of low-value test use.

Bottom line: Among commercially insured patients, a clinician’s prior imaging pattern and ownership of imaging equipment were strong independent predictors of low-value back pain and headache imaging.

Citation: Hong AS et al. Clinician-level predictors for ordering low-value imaging. JAMA Intern Med. 2017 Nov 1;177(11):1577-85.

The prevalence of gallstones is approximately 10% to 15% of the adult US population.^1,2 Most cases are asymptomatic, as gallstones are usually discovered incidentally during routine imaging for other abdominal conditions, and only about 20% of patients with asymptomatic gallstones develop clinically significant complications.^2,3

Nevertheless, gallstones carry significant healthcare costs. In 2004, the median inpatient cost for any gallstone-related disease was $11,584, with an overall annual cost of $6.2 billion.^4,5

Laparoscopic cholecystectomy is the standard treatment for symptomatic cholelithiasis. For asymptomatic cholelithasis, the usual approach is expectant management (“watch and wait”), but prophylactic cholecystectomy may be an option in certain patients at high risk.

CHEMICAL COMPOSITION

Gallstones can be classified into 2 main categories based on their predominant chemical composition: cholesterol or pigment.

Cholesterol gallstones

About 75% of gallstones are composed of cholesterol.^3,4 In the past, this type of stone was thought to be caused by gallbladder inflammation, bile stasis, and absorption of bile salts from damaged mucosa. However, it is now known that cholesterol gallstones are the result of biliary supersaturation caused by cholesterol hypersecretion into the gallbladder, gallbladder hypomotility, accelerated cholesterol nucleation and crystallization, and mucin gel accumulation.

Pigment gallstones

Black pigment gallstones account for 10% to 15% of all gallstones.⁶ They are caused by chronic hemolysis in association with supersaturation of bile with calcium hydrogen bilirubinate, along with deposition of calcium carbonate, phosphate, and inorganic salts.⁷

Brown pigment stones, accounting for 5% to 10% of all gallstones,⁶ are caused by infection in the obstructed bile ducts, where bacteria that produce beta-glucuronidase, phospholipase, and slime contribute to formation of the stone.^8,9

RISK FACTORS FOR GALLSTONES

Age. After age 40, the risk increases dramatically, with an incidence 4 times higher for those ages 40 to 69 than in younger people.¹⁰

Female sex. Women of reproductive age are 4 times more likely to develop gallstones than men, but this gap narrows after menopause.¹¹ The higher risk is attributed to female sex hormones, pregnancy, and oral contraceptive use. Estrogen decreases secretion of bile salts and increases secretion of cholesterol into the gallbladder, which leads to cholesterol supersaturation. Progesterone acts synergistically by causing hypomobility of the gallbladder, which in turn leads to bile stasis.^12,13

Ethnicity. The risk is higher in Mexican Americans and Native Americans than in other ethnic groups.¹⁴

Rapid weight loss, such as after bariatric surgery, occurs from decreased caloric intake and promotes bile stasis, while lipolysis increases cholesterol mobilization and secretion into the gallbladder. This creates an environment conducive to bile supersaturation with cholesterol, leading to gallstone formation.

Chronic hemolytic disorders carry an increased risk of developing calcium bilirubinate stones due to increased excretion of bilirubin during hemolysis.

Obesity and diabetes mellitus are both attributed to insulin resistance. Obesity also increases bile stasis and cholesterol saturation.

Most patients with gallstones (cholelithiasis) experience no symptoms. Their gallstones are often discovered incidentally during imaging tests for unrelated or unexplained abdominal symptoms. Most patients with asymptomatic gallstones remain symptom-free, while about 20% develop gallstone-related symptoms.^2,3

Abdominal pain is the most common symptom. The phrase biliary colic—suggesting pain that is fluctuating in nature—appears ubiquitously in the medical literature, but it does not correctly characterize the pain associated with gallstones.

Most patients with gallstone symptoms describe a constant and often severe pain in the right upper abdomen, epigastrium, or both, often persisting for 30 to 120 minutes. Symptoms are frequently reported in the epigastrium when only visceral pain fibers are stimulated due to gallbladder distention. This is usually called midline pain; however, pain occurs in the back and right shoulder in up to 60% of patients, with involvement of somatic fibers.^15,16 Gallstone pain is not relieved by change of position or passage of stool or gas.

Onset of symptoms more than an hour after eating or in the late evening or at night also  very strongly suggests biliary pain. Patients with a history of biliary pain are more likely to experience it again, with a 69% chance of developing recurrent pain within 2 years.¹⁷

GALLSTONE-RELATED COMPLICATIONS

Acute gallbladder inflammation (cholecystitis)

Gallbladder inflammation (cholecystitis) is the most common complication, occurring in up to 10% of symptomatic cases. Many patients with acute cholecystitis present with right upper quadrant pain that may be accompanied by anorexia, nausea, or vomiting. Inspiratory arrest on deep palpation of the right upper quadrant (Murphy sign) has a specificity of 79% to 96% for acute cholecystitis.²⁰ Markers of systemic inflammation such as fever, elevated white blood cell count, and elevated C-reactive protein are highly suggestive of acute cholecystitis.^20,21

Bile duct stones (choledocholithiasis)

Bile duct stones (choledocholithiasis) are detected in 3.4% to 12% of patients with gallstones.^22,23 Most stones in the common bile duct migrate there from the gallbladder via the cystic duct. Less commonly, primary duct stones form in the duct due to biliary stasis. Removing the gallbladder does not completely eliminate the risk of bile duct stones, as stones can remain or recur after surgery.

Bile duct stones can obstruct the common bile duct, which disrupts normal bile flow and leads to jaundice. Other symptoms may include pruritus, right upper quadrant pain, nausea, and vomiting. Serum levels of bilirubin, aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase are usually high.²⁴

Acute bacterial infection (cholangitis)

Acute bacterial infection of the biliary system (cholangitis) is usually associated with obstruction of the common bile duct. Common symptoms of acute cholangitis include right upper quadrant pain, fever, and jaundice (Charcot triad), and these are present in about 50% to 75% of cases.²¹ In severe cases, patients can develop altered mental status and septicemic shock in addition to the Charcot triad, a condition called the Reynold pentad. White blood cell counts and serum levels of C-reactive protein, bilirubin, aminotransferases, and alkaline phosphatase are usually elevated.²¹

Pancreatitis

Approximately 4% to 8% of patients with gallstones develop inflammation of the pancreas (pancreatitis).²⁵ The diagnosis of acute pancreatitis requires at least 2 of the following:^26,27

• Abdominal pain (typically epigastric, often radiating to the back)
• Amylase or lipase levels at least 3 times above the normal limit
• Imaging findings that suggest acute pancreatitis.

Gallstone-related pancreatitis should be considered if the ALT level is greater than 150 U/mL, which has a 97% specificity for gallstone-related pancreatitis.²⁸

Transabdominal ultrasonography, with a sensitivity of 84% to 89% and a specificity of up to 99%, is the test of choice for detecting gallstones.²⁹ The characteristic findings of acute cholecystitis on ultrasonography include enlargement of the gallbladder, thickening of the gallbladder wall, presence of pericholecystic fluid, and tenderness elicited by the ultrasound probe over the gallbladder (sonographic Murphy sign).

Scintigraphy as a second test

Acute cholecystitis is primarily a clinical diagnosis and typically does not require additional imaging beyond ultrasonography. When there is discordance between clinical and ultrasonographic findings, the most accurate second imaging test is scintigraphy of the biliary tract, usually performed with technetium-labeled hydroxy iminodiacetic acid. Given intravenously, the radionuclide is rapidly taken up by the liver and then secreted into the bile. In acute cholecystitis, the cystic duct is functionally occluded and the isotope does not enter the gallbladder, creating an imaging void compared with a normal appearance.

Scintigraphy is more sensitive than abdominal ultrasonography, with a sensitivity of up to 97% vs 81% to 88%, respectively.^29,30 The tests have about equal specificity.

Even though scintigraphy is more sensitive, abdominal ultrasonography is often the initial test for patients with suspected acute cholecystitis because it is more widely available, takes less time, does not involve radiation exposure, and can assess for the presence or absence of gallstones and dilation of the intra- and extrahepatic bile ducts.

Looking for stones in the common bile duct

When acute cholangitis due to choledocholithiasis is suspected, abdominal ultrasonography is a prudent initial test to look for gallstones or biliary dilation suggesting obstruction by stones in the common bile duct. Abdominal ultrasonography has only a 22% to 55% sensitivity for visualizing stones in the common bile duct, but it has a 77% to 87% sensitivity for detecting common bile duct dilation, a surrogate marker of stones.³¹

The normal bile duct diameter ranges from 3 to 6 mm, although mild dilation is often seen in older patients or after cholecystectomy or Roux-en-Y gastric bypass surgery.^32,33 Bile duct dilation of up to 10 mm can be considered normal in patients after cholecystectomy.³⁴ A normal-appearing bile duct on ultrasonography has a negative predictive value of 95% for excluding common bile duct stones.³¹

Endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP) have similar sensitivity (89%–94%, 85%–92%, and 89%–93%, respectively) and specificity (94%–95%, 93%–97%, and 100%, respectively) for detecting common bile duct stones.^35–37 EUS is superior to MRCP in detecting stones smaller than 6 mm.³⁸

ERCP should be reserved for managing rather than diagnosing common bile duct stones because of the risk of pancreatitis and perforation. Patients undergoing cholecystectomy who are suspected of having choledocholithiasis may undergo intraoperative cholangiography or laparoscopic common bile duct ultrasonography.

WATCH AND WAIT, OR INTERVENE?

Asymptomatic gallstones

Standard treatment for these patients is expectant management. Cholecystectomy is not recommended for patients with asymptomatic gallstones.⁴⁷ Nevertheless, some patients may benefit from prophylactic cholecystectomy. We and others⁴⁸ suggest considering cholecystectomy in the following patients.

Patients with chronic hemolytic anemia (including children with sickle cell anemia and spherocytosis). These patients have a higher risk of developing calcium bilirubinate stones, and cholecystectomy has improved outcomes.⁴⁹ It should be noted that most of these data come from pediatric populations and have been extrapolated to adults.

Native Americans, who have a higher risk of gallbladder cancer if they have gallstones.^2,50

Conversely, calcification of the gallbladder wall (“porcelain gallbladder”) is no longer considered an absolute indication for cholecystectomy. This condition was thought to be associated with a high rate of gallbladder carcinoma, but analyses of larger, more recent data sets found much smaller risks.^51,52 Further, cholecystectomy in these patients was found to be associated with high rates of postoperative complications. Thus, prophylactic cholecystectomy is no longer recommended in asymptomatic cases of porcelain gallbladder.

In addition, concomitant cholecystectomy in patients undergoing bariatric surgery is no longer considered the therapeutic standard. Historically, cholecystectomy was performed in these patients because of the increased risk of gallstones associated with rapid weight loss after surgery. However, research now weighs against concomitant cholecystectomy with bariatric surgery and most other abdominal surgeries for asymptomatic gallstones.⁵³

Based on information in reference 48.

For patients experiencing acute cholecystitis, laparoscopic cholecystectomy within 72 hours is recommended.⁴⁸ There were safety concerns regarding higher rates of morbidity and conversion from laparoscopic to open cholecystectomy in patients who underwent surgery before the acute cholecystitis episode had settled. However, a large meta-analysis found no significant difference between early and delayed laparoscopic cholecystectomy in bile duct injury or conversion rates.⁵⁴ Further, early cholecystectomy—defined as within 1 week of symptom onset—has been found to reduce gallstone-related complications, shorten hospital stays, and lower costs.^55–57 If the patient cannot undergo surgery, percutaneous cholecystotomy or novel endoscopic gallbladder drainage interventions can be used.

Reprinted from ASGE Standards of Practice Committee; Maple JT, Ben-Menachem T, Anderson MA, et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointest Endoscp 2010; 71:1–9 with permission from Elsevier.

Several variables predict the presence of bile duct stones in patients who have symptoms (Table 4). Based on these predictors, the ASGE classifies the probabilities as low (< 10%), intermediate (10% to 50%), and high (> 50%)³¹:

• 
  Low-risk patients require no further evaluation of the common bile duct
• High-risk patients should undergo preoperative ERCP and stone extraction if needed
• Intermediate-risk patients should undergo preoperative imaging with EUS or MRCP or intraoperative bile duct evaluation, depending on the availability, costs, and local expertise.

Patients with associated cholangitis should be given intravenous fluids and broad-spectrum antibiotics. Biliary decompression should be done as early as possible to decrease the risk of morbidity and mortality. For acute cholangitis, ERCP is the treatment of choice.²⁵

Patients with acute gallstone pancreatitis should receive conservative management with intravenous isotonic solutions and pain control, followed by laparoscopic cholecystectomy.⁴⁸

The timing of laparoscopic cholecystectomy in acute gallstone pancreatitis has been debated. Studies conducted during the era of open cholecystectomy reported similar or worse outcomes if cholecystectomy was done sooner rather than later.

However, in 1999, Uhl et al⁵⁸ reported that 48 of 77 patients admitted with acute gallstone pancreatitis were able to undergo laparoscopic cholecystectomy during the same admission. Success rates were 85% (30 of 35 patients) in those with mild disease and 62% (8 of 13 patients) in those with severe disease. They concluded laparoscopic cholecystectomy could be safely performed within 7 days in patients with mild disease, whereas in severe disease at least 3 weeks should elapse because of the risk of infection.

In a randomized trial published in 2010, Aboulian et al⁵⁹ reported that hospital length of stay (the primary end point) was shorter in 25 patients who underwent laparoscopic cholecystectomy early (within 48 hours of admission) than in 25 patients who underwent surgery after abdominal pain had resolved and laboratory enzymes showed a normalizing trend, 3.5 vs 5.8 days (P = .0016). Rates of perioperative complications and need for conversion to open surgery were similar between the 2 groups.

If there is associated cholangitis, patients should also be given broad-spectrum antibiotics and should undergo ERCP within 24 hours of admission.^25–27

SUMMARY

Gallstones are common in US adults. Abdominal ultrasonography is the diagnostic imaging test of choice to detect gallbladder stones and assess for findings suggestive of acute cholecystitis and dilation of the common bile duct. Fortunately, most gallstones are asymptomatic and can usually be managed expectantly. In patients who have symptoms or have gallstone complications, laparoscopic cholecystectomy is the standard of care.

The prevalence of gallstones is approximately 10% to 15% of the adult US population.^1,2 Most cases are asymptomatic, as gallstones are usually discovered incidentally during routine imaging for other abdominal conditions, and only about 20% of patients with asymptomatic gallstones develop clinically significant complications.^2,3

Nevertheless, gallstones carry significant healthcare costs. In 2004, the median inpatient cost for any gallstone-related disease was $11,584, with an overall annual cost of $6.2 billion.^4,5

Laparoscopic cholecystectomy is the standard treatment for symptomatic cholelithiasis. For asymptomatic cholelithasis, the usual approach is expectant management (“watch and wait”), but prophylactic cholecystectomy may be an option in certain patients at high risk.

CHEMICAL COMPOSITION

Gallstones can be classified into 2 main categories based on their predominant chemical composition: cholesterol or pigment.

Cholesterol gallstones

About 75% of gallstones are composed of cholesterol.^3,4 In the past, this type of stone was thought to be caused by gallbladder inflammation, bile stasis, and absorption of bile salts from damaged mucosa. However, it is now known that cholesterol gallstones are the result of biliary supersaturation caused by cholesterol hypersecretion into the gallbladder, gallbladder hypomotility, accelerated cholesterol nucleation and crystallization, and mucin gel accumulation.

Pigment gallstones

Black pigment gallstones account for 10% to 15% of all gallstones.⁶ They are caused by chronic hemolysis in association with supersaturation of bile with calcium hydrogen bilirubinate, along with deposition of calcium carbonate, phosphate, and inorganic salts.⁷

Brown pigment stones, accounting for 5% to 10% of all gallstones,⁶ are caused by infection in the obstructed bile ducts, where bacteria that produce beta-glucuronidase, phospholipase, and slime contribute to formation of the stone.^8,9

RISK FACTORS FOR GALLSTONES

Age. After age 40, the risk increases dramatically, with an incidence 4 times higher for those ages 40 to 69 than in younger people.¹⁰

Female sex. Women of reproductive age are 4 times more likely to develop gallstones than men, but this gap narrows after menopause.¹¹ The higher risk is attributed to female sex hormones, pregnancy, and oral contraceptive use. Estrogen decreases secretion of bile salts and increases secretion of cholesterol into the gallbladder, which leads to cholesterol supersaturation. Progesterone acts synergistically by causing hypomobility of the gallbladder, which in turn leads to bile stasis.^12,13

Ethnicity. The risk is higher in Mexican Americans and Native Americans than in other ethnic groups.¹⁴

Rapid weight loss, such as after bariatric surgery, occurs from decreased caloric intake and promotes bile stasis, while lipolysis increases cholesterol mobilization and secretion into the gallbladder. This creates an environment conducive to bile supersaturation with cholesterol, leading to gallstone formation.

Chronic hemolytic disorders carry an increased risk of developing calcium bilirubinate stones due to increased excretion of bilirubin during hemolysis.

Obesity and diabetes mellitus are both attributed to insulin resistance. Obesity also increases bile stasis and cholesterol saturation.

Most patients with gallstones (cholelithiasis) experience no symptoms. Their gallstones are often discovered incidentally during imaging tests for unrelated or unexplained abdominal symptoms. Most patients with asymptomatic gallstones remain symptom-free, while about 20% develop gallstone-related symptoms.^2,3

Abdominal pain is the most common symptom. The phrase biliary colic—suggesting pain that is fluctuating in nature—appears ubiquitously in the medical literature, but it does not correctly characterize the pain associated with gallstones.

Most patients with gallstone symptoms describe a constant and often severe pain in the right upper abdomen, epigastrium, or both, often persisting for 30 to 120 minutes. Symptoms are frequently reported in the epigastrium when only visceral pain fibers are stimulated due to gallbladder distention. This is usually called midline pain; however, pain occurs in the back and right shoulder in up to 60% of patients, with involvement of somatic fibers.^15,16 Gallstone pain is not relieved by change of position or passage of stool or gas.

Onset of symptoms more than an hour after eating or in the late evening or at night also  very strongly suggests biliary pain. Patients with a history of biliary pain are more likely to experience it again, with a 69% chance of developing recurrent pain within 2 years.¹⁷

GALLSTONE-RELATED COMPLICATIONS

Acute gallbladder inflammation (cholecystitis)

Gallbladder inflammation (cholecystitis) is the most common complication, occurring in up to 10% of symptomatic cases. Many patients with acute cholecystitis present with right upper quadrant pain that may be accompanied by anorexia, nausea, or vomiting. Inspiratory arrest on deep palpation of the right upper quadrant (Murphy sign) has a specificity of 79% to 96% for acute cholecystitis.²⁰ Markers of systemic inflammation such as fever, elevated white blood cell count, and elevated C-reactive protein are highly suggestive of acute cholecystitis.^20,21

Bile duct stones (choledocholithiasis)

Bile duct stones (choledocholithiasis) are detected in 3.4% to 12% of patients with gallstones.^22,23 Most stones in the common bile duct migrate there from the gallbladder via the cystic duct. Less commonly, primary duct stones form in the duct due to biliary stasis. Removing the gallbladder does not completely eliminate the risk of bile duct stones, as stones can remain or recur after surgery.

Bile duct stones can obstruct the common bile duct, which disrupts normal bile flow and leads to jaundice. Other symptoms may include pruritus, right upper quadrant pain, nausea, and vomiting. Serum levels of bilirubin, aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase are usually high.²⁴

Acute bacterial infection (cholangitis)

Acute bacterial infection of the biliary system (cholangitis) is usually associated with obstruction of the common bile duct. Common symptoms of acute cholangitis include right upper quadrant pain, fever, and jaundice (Charcot triad), and these are present in about 50% to 75% of cases.²¹ In severe cases, patients can develop altered mental status and septicemic shock in addition to the Charcot triad, a condition called the Reynold pentad. White blood cell counts and serum levels of C-reactive protein, bilirubin, aminotransferases, and alkaline phosphatase are usually elevated.²¹

Pancreatitis

Approximately 4% to 8% of patients with gallstones develop inflammation of the pancreas (pancreatitis).²⁵ The diagnosis of acute pancreatitis requires at least 2 of the following:^26,27

• Abdominal pain (typically epigastric, often radiating to the back)
• Amylase or lipase levels at least 3 times above the normal limit
• Imaging findings that suggest acute pancreatitis.

Gallstone-related pancreatitis should be considered if the ALT level is greater than 150 U/mL, which has a 97% specificity for gallstone-related pancreatitis.²⁸

Transabdominal ultrasonography, with a sensitivity of 84% to 89% and a specificity of up to 99%, is the test of choice for detecting gallstones.²⁹ The characteristic findings of acute cholecystitis on ultrasonography include enlargement of the gallbladder, thickening of the gallbladder wall, presence of pericholecystic fluid, and tenderness elicited by the ultrasound probe over the gallbladder (sonographic Murphy sign).

Scintigraphy as a second test

Acute cholecystitis is primarily a clinical diagnosis and typically does not require additional imaging beyond ultrasonography. When there is discordance between clinical and ultrasonographic findings, the most accurate second imaging test is scintigraphy of the biliary tract, usually performed with technetium-labeled hydroxy iminodiacetic acid. Given intravenously, the radionuclide is rapidly taken up by the liver and then secreted into the bile. In acute cholecystitis, the cystic duct is functionally occluded and the isotope does not enter the gallbladder, creating an imaging void compared with a normal appearance.

Scintigraphy is more sensitive than abdominal ultrasonography, with a sensitivity of up to 97% vs 81% to 88%, respectively.^29,30 The tests have about equal specificity.

Even though scintigraphy is more sensitive, abdominal ultrasonography is often the initial test for patients with suspected acute cholecystitis because it is more widely available, takes less time, does not involve radiation exposure, and can assess for the presence or absence of gallstones and dilation of the intra- and extrahepatic bile ducts.

Looking for stones in the common bile duct

When acute cholangitis due to choledocholithiasis is suspected, abdominal ultrasonography is a prudent initial test to look for gallstones or biliary dilation suggesting obstruction by stones in the common bile duct. Abdominal ultrasonography has only a 22% to 55% sensitivity for visualizing stones in the common bile duct, but it has a 77% to 87% sensitivity for detecting common bile duct dilation, a surrogate marker of stones.³¹

The normal bile duct diameter ranges from 3 to 6 mm, although mild dilation is often seen in older patients or after cholecystectomy or Roux-en-Y gastric bypass surgery.^32,33 Bile duct dilation of up to 10 mm can be considered normal in patients after cholecystectomy.³⁴ A normal-appearing bile duct on ultrasonography has a negative predictive value of 95% for excluding common bile duct stones.³¹

Endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP) have similar sensitivity (89%–94%, 85%–92%, and 89%–93%, respectively) and specificity (94%–95%, 93%–97%, and 100%, respectively) for detecting common bile duct stones.^35–37 EUS is superior to MRCP in detecting stones smaller than 6 mm.³⁸

ERCP should be reserved for managing rather than diagnosing common bile duct stones because of the risk of pancreatitis and perforation. Patients undergoing cholecystectomy who are suspected of having choledocholithiasis may undergo intraoperative cholangiography or laparoscopic common bile duct ultrasonography.

WATCH AND WAIT, OR INTERVENE?

Asymptomatic gallstones

Standard treatment for these patients is expectant management. Cholecystectomy is not recommended for patients with asymptomatic gallstones.⁴⁷ Nevertheless, some patients may benefit from prophylactic cholecystectomy. We and others⁴⁸ suggest considering cholecystectomy in the following patients.

Patients with chronic hemolytic anemia (including children with sickle cell anemia and spherocytosis). These patients have a higher risk of developing calcium bilirubinate stones, and cholecystectomy has improved outcomes.⁴⁹ It should be noted that most of these data come from pediatric populations and have been extrapolated to adults.

Native Americans, who have a higher risk of gallbladder cancer if they have gallstones.^2,50

Conversely, calcification of the gallbladder wall (“porcelain gallbladder”) is no longer considered an absolute indication for cholecystectomy. This condition was thought to be associated with a high rate of gallbladder carcinoma, but analyses of larger, more recent data sets found much smaller risks.^51,52 Further, cholecystectomy in these patients was found to be associated with high rates of postoperative complications. Thus, prophylactic cholecystectomy is no longer recommended in asymptomatic cases of porcelain gallbladder.

In addition, concomitant cholecystectomy in patients undergoing bariatric surgery is no longer considered the therapeutic standard. Historically, cholecystectomy was performed in these patients because of the increased risk of gallstones associated with rapid weight loss after surgery. However, research now weighs against concomitant cholecystectomy with bariatric surgery and most other abdominal surgeries for asymptomatic gallstones.⁵³

Based on information in reference 48.

For patients experiencing acute cholecystitis, laparoscopic cholecystectomy within 72 hours is recommended.⁴⁸ There were safety concerns regarding higher rates of morbidity and conversion from laparoscopic to open cholecystectomy in patients who underwent surgery before the acute cholecystitis episode had settled. However, a large meta-analysis found no significant difference between early and delayed laparoscopic cholecystectomy in bile duct injury or conversion rates.⁵⁴ Further, early cholecystectomy—defined as within 1 week of symptom onset—has been found to reduce gallstone-related complications, shorten hospital stays, and lower costs.^55–57 If the patient cannot undergo surgery, percutaneous cholecystotomy or novel endoscopic gallbladder drainage interventions can be used.

Reprinted from ASGE Standards of Practice Committee; Maple JT, Ben-Menachem T, Anderson MA, et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointest Endoscp 2010; 71:1–9 with permission from Elsevier.

Several variables predict the presence of bile duct stones in patients who have symptoms (Table 4). Based on these predictors, the ASGE classifies the probabilities as low (< 10%), intermediate (10% to 50%), and high (> 50%)³¹:

• 
  Low-risk patients require no further evaluation of the common bile duct
• High-risk patients should undergo preoperative ERCP and stone extraction if needed
• Intermediate-risk patients should undergo preoperative imaging with EUS or MRCP or intraoperative bile duct evaluation, depending on the availability, costs, and local expertise.

Patients with associated cholangitis should be given intravenous fluids and broad-spectrum antibiotics. Biliary decompression should be done as early as possible to decrease the risk of morbidity and mortality. For acute cholangitis, ERCP is the treatment of choice.²⁵

Patients with acute gallstone pancreatitis should receive conservative management with intravenous isotonic solutions and pain control, followed by laparoscopic cholecystectomy.⁴⁸

The timing of laparoscopic cholecystectomy in acute gallstone pancreatitis has been debated. Studies conducted during the era of open cholecystectomy reported similar or worse outcomes if cholecystectomy was done sooner rather than later.

However, in 1999, Uhl et al⁵⁸ reported that 48 of 77 patients admitted with acute gallstone pancreatitis were able to undergo laparoscopic cholecystectomy during the same admission. Success rates were 85% (30 of 35 patients) in those with mild disease and 62% (8 of 13 patients) in those with severe disease. They concluded laparoscopic cholecystectomy could be safely performed within 7 days in patients with mild disease, whereas in severe disease at least 3 weeks should elapse because of the risk of infection.

In a randomized trial published in 2010, Aboulian et al⁵⁹ reported that hospital length of stay (the primary end point) was shorter in 25 patients who underwent laparoscopic cholecystectomy early (within 48 hours of admission) than in 25 patients who underwent surgery after abdominal pain had resolved and laboratory enzymes showed a normalizing trend, 3.5 vs 5.8 days (P = .0016). Rates of perioperative complications and need for conversion to open surgery were similar between the 2 groups.

If there is associated cholangitis, patients should also be given broad-spectrum antibiotics and should undergo ERCP within 24 hours of admission.^25–27

SUMMARY

Gallstones are common in US adults. Abdominal ultrasonography is the diagnostic imaging test of choice to detect gallbladder stones and assess for findings suggestive of acute cholecystitis and dilation of the common bile duct. Fortunately, most gallstones are asymptomatic and can usually be managed expectantly. In patients who have symptoms or have gallstone complications, laparoscopic cholecystectomy is the standard of care.

The prevalence of gallstones is approximately 10% to 15% of the adult US population.^1,2 Most cases are asymptomatic, as gallstones are usually discovered incidentally during routine imaging for other abdominal conditions, and only about 20% of patients with asymptomatic gallstones develop clinically significant complications.^2,3

Nevertheless, gallstones carry significant healthcare costs. In 2004, the median inpatient cost for any gallstone-related disease was $11,584, with an overall annual cost of $6.2 billion.^4,5

Laparoscopic cholecystectomy is the standard treatment for symptomatic cholelithiasis. For asymptomatic cholelithasis, the usual approach is expectant management (“watch and wait”), but prophylactic cholecystectomy may be an option in certain patients at high risk.

CHEMICAL COMPOSITION

Gallstones can be classified into 2 main categories based on their predominant chemical composition: cholesterol or pigment.

Cholesterol gallstones

About 75% of gallstones are composed of cholesterol.^3,4 In the past, this type of stone was thought to be caused by gallbladder inflammation, bile stasis, and absorption of bile salts from damaged mucosa. However, it is now known that cholesterol gallstones are the result of biliary supersaturation caused by cholesterol hypersecretion into the gallbladder, gallbladder hypomotility, accelerated cholesterol nucleation and crystallization, and mucin gel accumulation.

Pigment gallstones

Black pigment gallstones account for 10% to 15% of all gallstones.⁶ They are caused by chronic hemolysis in association with supersaturation of bile with calcium hydrogen bilirubinate, along with deposition of calcium carbonate, phosphate, and inorganic salts.⁷

Brown pigment stones, accounting for 5% to 10% of all gallstones,⁶ are caused by infection in the obstructed bile ducts, where bacteria that produce beta-glucuronidase, phospholipase, and slime contribute to formation of the stone.^8,9

RISK FACTORS FOR GALLSTONES

Age. After age 40, the risk increases dramatically, with an incidence 4 times higher for those ages 40 to 69 than in younger people.¹⁰

Female sex. Women of reproductive age are 4 times more likely to develop gallstones than men, but this gap narrows after menopause.¹¹ The higher risk is attributed to female sex hormones, pregnancy, and oral contraceptive use. Estrogen decreases secretion of bile salts and increases secretion of cholesterol into the gallbladder, which leads to cholesterol supersaturation. Progesterone acts synergistically by causing hypomobility of the gallbladder, which in turn leads to bile stasis.^12,13

Ethnicity. The risk is higher in Mexican Americans and Native Americans than in other ethnic groups.¹⁴

Rapid weight loss, such as after bariatric surgery, occurs from decreased caloric intake and promotes bile stasis, while lipolysis increases cholesterol mobilization and secretion into the gallbladder. This creates an environment conducive to bile supersaturation with cholesterol, leading to gallstone formation.

Chronic hemolytic disorders carry an increased risk of developing calcium bilirubinate stones due to increased excretion of bilirubin during hemolysis.

Obesity and diabetes mellitus are both attributed to insulin resistance. Obesity also increases bile stasis and cholesterol saturation.

Most patients with gallstones (cholelithiasis) experience no symptoms. Their gallstones are often discovered incidentally during imaging tests for unrelated or unexplained abdominal symptoms. Most patients with asymptomatic gallstones remain symptom-free, while about 20% develop gallstone-related symptoms.^2,3

Abdominal pain is the most common symptom. The phrase biliary colic—suggesting pain that is fluctuating in nature—appears ubiquitously in the medical literature, but it does not correctly characterize the pain associated with gallstones.

Most patients with gallstone symptoms describe a constant and often severe pain in the right upper abdomen, epigastrium, or both, often persisting for 30 to 120 minutes. Symptoms are frequently reported in the epigastrium when only visceral pain fibers are stimulated due to gallbladder distention. This is usually called midline pain; however, pain occurs in the back and right shoulder in up to 60% of patients, with involvement of somatic fibers.^15,16 Gallstone pain is not relieved by change of position or passage of stool or gas.

Onset of symptoms more than an hour after eating or in the late evening or at night also  very strongly suggests biliary pain. Patients with a history of biliary pain are more likely to experience it again, with a 69% chance of developing recurrent pain within 2 years.¹⁷

GALLSTONE-RELATED COMPLICATIONS

Acute gallbladder inflammation (cholecystitis)

Gallbladder inflammation (cholecystitis) is the most common complication, occurring in up to 10% of symptomatic cases. Many patients with acute cholecystitis present with right upper quadrant pain that may be accompanied by anorexia, nausea, or vomiting. Inspiratory arrest on deep palpation of the right upper quadrant (Murphy sign) has a specificity of 79% to 96% for acute cholecystitis.²⁰ Markers of systemic inflammation such as fever, elevated white blood cell count, and elevated C-reactive protein are highly suggestive of acute cholecystitis.^20,21

Bile duct stones (choledocholithiasis)

Bile duct stones (choledocholithiasis) are detected in 3.4% to 12% of patients with gallstones.^22,23 Most stones in the common bile duct migrate there from the gallbladder via the cystic duct. Less commonly, primary duct stones form in the duct due to biliary stasis. Removing the gallbladder does not completely eliminate the risk of bile duct stones, as stones can remain or recur after surgery.

Bile duct stones can obstruct the common bile duct, which disrupts normal bile flow and leads to jaundice. Other symptoms may include pruritus, right upper quadrant pain, nausea, and vomiting. Serum levels of bilirubin, aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase are usually high.²⁴

Acute bacterial infection (cholangitis)

Acute bacterial infection of the biliary system (cholangitis) is usually associated with obstruction of the common bile duct. Common symptoms of acute cholangitis include right upper quadrant pain, fever, and jaundice (Charcot triad), and these are present in about 50% to 75% of cases.²¹ In severe cases, patients can develop altered mental status and septicemic shock in addition to the Charcot triad, a condition called the Reynold pentad. White blood cell counts and serum levels of C-reactive protein, bilirubin, aminotransferases, and alkaline phosphatase are usually elevated.²¹

Pancreatitis

Approximately 4% to 8% of patients with gallstones develop inflammation of the pancreas (pancreatitis).²⁵ The diagnosis of acute pancreatitis requires at least 2 of the following:^26,27

• Abdominal pain (typically epigastric, often radiating to the back)
• Amylase or lipase levels at least 3 times above the normal limit
• Imaging findings that suggest acute pancreatitis.

Gallstone-related pancreatitis should be considered if the ALT level is greater than 150 U/mL, which has a 97% specificity for gallstone-related pancreatitis.²⁸

Transabdominal ultrasonography, with a sensitivity of 84% to 89% and a specificity of up to 99%, is the test of choice for detecting gallstones.²⁹ The characteristic findings of acute cholecystitis on ultrasonography include enlargement of the gallbladder, thickening of the gallbladder wall, presence of pericholecystic fluid, and tenderness elicited by the ultrasound probe over the gallbladder (sonographic Murphy sign).

Scintigraphy as a second test

Acute cholecystitis is primarily a clinical diagnosis and typically does not require additional imaging beyond ultrasonography. When there is discordance between clinical and ultrasonographic findings, the most accurate second imaging test is scintigraphy of the biliary tract, usually performed with technetium-labeled hydroxy iminodiacetic acid. Given intravenously, the radionuclide is rapidly taken up by the liver and then secreted into the bile. In acute cholecystitis, the cystic duct is functionally occluded and the isotope does not enter the gallbladder, creating an imaging void compared with a normal appearance.

Scintigraphy is more sensitive than abdominal ultrasonography, with a sensitivity of up to 97% vs 81% to 88%, respectively.^29,30 The tests have about equal specificity.

Even though scintigraphy is more sensitive, abdominal ultrasonography is often the initial test for patients with suspected acute cholecystitis because it is more widely available, takes less time, does not involve radiation exposure, and can assess for the presence or absence of gallstones and dilation of the intra- and extrahepatic bile ducts.

Looking for stones in the common bile duct

When acute cholangitis due to choledocholithiasis is suspected, abdominal ultrasonography is a prudent initial test to look for gallstones or biliary dilation suggesting obstruction by stones in the common bile duct. Abdominal ultrasonography has only a 22% to 55% sensitivity for visualizing stones in the common bile duct, but it has a 77% to 87% sensitivity for detecting common bile duct dilation, a surrogate marker of stones.³¹

The normal bile duct diameter ranges from 3 to 6 mm, although mild dilation is often seen in older patients or after cholecystectomy or Roux-en-Y gastric bypass surgery.^32,33 Bile duct dilation of up to 10 mm can be considered normal in patients after cholecystectomy.³⁴ A normal-appearing bile duct on ultrasonography has a negative predictive value of 95% for excluding common bile duct stones.³¹

Endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP) have similar sensitivity (89%–94%, 85%–92%, and 89%–93%, respectively) and specificity (94%–95%, 93%–97%, and 100%, respectively) for detecting common bile duct stones.^35–37 EUS is superior to MRCP in detecting stones smaller than 6 mm.³⁸

ERCP should be reserved for managing rather than diagnosing common bile duct stones because of the risk of pancreatitis and perforation. Patients undergoing cholecystectomy who are suspected of having choledocholithiasis may undergo intraoperative cholangiography or laparoscopic common bile duct ultrasonography.

WATCH AND WAIT, OR INTERVENE?

Asymptomatic gallstones

Standard treatment for these patients is expectant management. Cholecystectomy is not recommended for patients with asymptomatic gallstones.⁴⁷ Nevertheless, some patients may benefit from prophylactic cholecystectomy. We and others⁴⁸ suggest considering cholecystectomy in the following patients.

Patients with chronic hemolytic anemia (including children with sickle cell anemia and spherocytosis). These patients have a higher risk of developing calcium bilirubinate stones, and cholecystectomy has improved outcomes.⁴⁹ It should be noted that most of these data come from pediatric populations and have been extrapolated to adults.

Native Americans, who have a higher risk of gallbladder cancer if they have gallstones.^2,50

Conversely, calcification of the gallbladder wall (“porcelain gallbladder”) is no longer considered an absolute indication for cholecystectomy. This condition was thought to be associated with a high rate of gallbladder carcinoma, but analyses of larger, more recent data sets found much smaller risks.^51,52 Further, cholecystectomy in these patients was found to be associated with high rates of postoperative complications. Thus, prophylactic cholecystectomy is no longer recommended in asymptomatic cases of porcelain gallbladder.

In addition, concomitant cholecystectomy in patients undergoing bariatric surgery is no longer considered the therapeutic standard. Historically, cholecystectomy was performed in these patients because of the increased risk of gallstones associated with rapid weight loss after surgery. However, research now weighs against concomitant cholecystectomy with bariatric surgery and most other abdominal surgeries for asymptomatic gallstones.⁵³

Based on information in reference 48.

For patients experiencing acute cholecystitis, laparoscopic cholecystectomy within 72 hours is recommended.⁴⁸ There were safety concerns regarding higher rates of morbidity and conversion from laparoscopic to open cholecystectomy in patients who underwent surgery before the acute cholecystitis episode had settled. However, a large meta-analysis found no significant difference between early and delayed laparoscopic cholecystectomy in bile duct injury or conversion rates.⁵⁴ Further, early cholecystectomy—defined as within 1 week of symptom onset—has been found to reduce gallstone-related complications, shorten hospital stays, and lower costs.^55–57 If the patient cannot undergo surgery, percutaneous cholecystotomy or novel endoscopic gallbladder drainage interventions can be used.

Reprinted from ASGE Standards of Practice Committee; Maple JT, Ben-Menachem T, Anderson MA, et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointest Endoscp 2010; 71:1–9 with permission from Elsevier.

Several variables predict the presence of bile duct stones in patients who have symptoms (Table 4). Based on these predictors, the ASGE classifies the probabilities as low (< 10%), intermediate (10% to 50%), and high (> 50%)³¹:

• 
  Low-risk patients require no further evaluation of the common bile duct
• High-risk patients should undergo preoperative ERCP and stone extraction if needed
• Intermediate-risk patients should undergo preoperative imaging with EUS or MRCP or intraoperative bile duct evaluation, depending on the availability, costs, and local expertise.

Patients with associated cholangitis should be given intravenous fluids and broad-spectrum antibiotics. Biliary decompression should be done as early as possible to decrease the risk of morbidity and mortality. For acute cholangitis, ERCP is the treatment of choice.²⁵

Patients with acute gallstone pancreatitis should receive conservative management with intravenous isotonic solutions and pain control, followed by laparoscopic cholecystectomy.⁴⁸

The timing of laparoscopic cholecystectomy in acute gallstone pancreatitis has been debated. Studies conducted during the era of open cholecystectomy reported similar or worse outcomes if cholecystectomy was done sooner rather than later.

However, in 1999, Uhl et al⁵⁸ reported that 48 of 77 patients admitted with acute gallstone pancreatitis were able to undergo laparoscopic cholecystectomy during the same admission. Success rates were 85% (30 of 35 patients) in those with mild disease and 62% (8 of 13 patients) in those with severe disease. They concluded laparoscopic cholecystectomy could be safely performed within 7 days in patients with mild disease, whereas in severe disease at least 3 weeks should elapse because of the risk of infection.

In a randomized trial published in 2010, Aboulian et al⁵⁹ reported that hospital length of stay (the primary end point) was shorter in 25 patients who underwent laparoscopic cholecystectomy early (within 48 hours of admission) than in 25 patients who underwent surgery after abdominal pain had resolved and laboratory enzymes showed a normalizing trend, 3.5 vs 5.8 days (P = .0016). Rates of perioperative complications and need for conversion to open surgery were similar between the 2 groups.

If there is associated cholangitis, patients should also be given broad-spectrum antibiotics and should undergo ERCP within 24 hours of admission.^25–27

SUMMARY

Gallstones are common in US adults. Abdominal ultrasonography is the diagnostic imaging test of choice to detect gallbladder stones and assess for findings suggestive of acute cholecystitis and dilation of the common bile duct. Fortunately, most gallstones are asymptomatic and can usually be managed expectantly. In patients who have symptoms or have gallstone complications, laparoscopic cholecystectomy is the standard of care.

A 46-year-old man with poorly controlled hypertension presented with the sudden onset of chest pain and shortness of breath. His blood pressure was 158/96 mm Hg and his left ventricular ejection fraction was less than 20%. He was admitted to the hospital for newly diagnosed heart failure.

SACCULAR AORTIC ANEURYSMS

This case shows the value of carefully examining the chest radiograph, especially behind the heart.

Saccular aneurysms of the descending thoracic aorta are rare and can be easily missed if asymptomatic. They are less common than fusiform aneurysms and may be more prone to rupture. Shang et al¹ identified atherosclerosis as the most frequent cause of saccular aneurysms of the thoracic aorta. However, they can be caused by other inflammatory conditions and infections.¹

Without surgical repair, thoracic aortic aneurysms larger than 6 cm have higher rates of expansion and rupture (a 20% 6-year cumulative risk) than smaller ones.² Mid-descending aortic aneurysms expand faster than those of the ascending aorta.³

Indications for surgery include rupture, severe chest pain, compressive symptoms, large size (eg, ≥ 5.5 cm for asymptomatic descending thoracic aneurysms), and rapid growth rate (≥ 10 mm per year), all of which are associated with a higher mortality rate.⁴

Endovascular grafting should be strongly considered in patients who have significant comorbidities, but this approach may have poorer long-term outcomes compared with open surgery. Blood pressure should be lowered as far as the patient can tolerate without adverse effects, usually with a beta-blocker along with either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker.⁴

Statin therapy to lower the low-density lipoprotein cholesterol level to less than 70 mg/dL is also needed to reduce the risk of complications and cardiovascular disease.

All patients with saccular aortic aneurysm should be followed closely and be evaluated for surgery.

A 46-year-old man with poorly controlled hypertension presented with the sudden onset of chest pain and shortness of breath. His blood pressure was 158/96 mm Hg and his left ventricular ejection fraction was less than 20%. He was admitted to the hospital for newly diagnosed heart failure.

SACCULAR AORTIC ANEURYSMS

This case shows the value of carefully examining the chest radiograph, especially behind the heart.

Saccular aneurysms of the descending thoracic aorta are rare and can be easily missed if asymptomatic. They are less common than fusiform aneurysms and may be more prone to rupture. Shang et al¹ identified atherosclerosis as the most frequent cause of saccular aneurysms of the thoracic aorta. However, they can be caused by other inflammatory conditions and infections.¹

Without surgical repair, thoracic aortic aneurysms larger than 6 cm have higher rates of expansion and rupture (a 20% 6-year cumulative risk) than smaller ones.² Mid-descending aortic aneurysms expand faster than those of the ascending aorta.³

Indications for surgery include rupture, severe chest pain, compressive symptoms, large size (eg, ≥ 5.5 cm for asymptomatic descending thoracic aneurysms), and rapid growth rate (≥ 10 mm per year), all of which are associated with a higher mortality rate.⁴

Endovascular grafting should be strongly considered in patients who have significant comorbidities, but this approach may have poorer long-term outcomes compared with open surgery. Blood pressure should be lowered as far as the patient can tolerate without adverse effects, usually with a beta-blocker along with either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker.⁴

Statin therapy to lower the low-density lipoprotein cholesterol level to less than 70 mg/dL is also needed to reduce the risk of complications and cardiovascular disease.

All patients with saccular aortic aneurysm should be followed closely and be evaluated for surgery.

A 46-year-old man with poorly controlled hypertension presented with the sudden onset of chest pain and shortness of breath. His blood pressure was 158/96 mm Hg and his left ventricular ejection fraction was less than 20%. He was admitted to the hospital for newly diagnosed heart failure.

SACCULAR AORTIC ANEURYSMS

This case shows the value of carefully examining the chest radiograph, especially behind the heart.

Saccular aneurysms of the descending thoracic aorta are rare and can be easily missed if asymptomatic. They are less common than fusiform aneurysms and may be more prone to rupture. Shang et al¹ identified atherosclerosis as the most frequent cause of saccular aneurysms of the thoracic aorta. However, they can be caused by other inflammatory conditions and infections.¹

Without surgical repair, thoracic aortic aneurysms larger than 6 cm have higher rates of expansion and rupture (a 20% 6-year cumulative risk) than smaller ones.² Mid-descending aortic aneurysms expand faster than those of the ascending aorta.³

Indications for surgery include rupture, severe chest pain, compressive symptoms, large size (eg, ≥ 5.5 cm for asymptomatic descending thoracic aneurysms), and rapid growth rate (≥ 10 mm per year), all of which are associated with a higher mortality rate.⁴

Endovascular grafting should be strongly considered in patients who have significant comorbidities, but this approach may have poorer long-term outcomes compared with open surgery. Blood pressure should be lowered as far as the patient can tolerate without adverse effects, usually with a beta-blocker along with either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker.⁴

Statin therapy to lower the low-density lipoprotein cholesterol level to less than 70 mg/dL is also needed to reduce the risk of complications and cardiovascular disease.

All patients with saccular aortic aneurysm should be followed closely and be evaluated for surgery.

Ultrasonography has been used to evaluate musculoskeletal problems for decades but has only recently become more widely available in the United States. Advances in technology and physician familiarity are increasing its role in orthopedic imaging.

See related editorial

No single imaging method can yield all musculoskeletal diagnoses. Like any imaging technique, ultrasonography has strengths and weaknesses specific to orthopedics. Radiography, computed tomography (CT), and magnetic resonance imaging (MRI) play important roles for investigating musculoskeletal problems and are complementary to each other and to ultrasonography.

To help clinicians make informed decisions about ordering musculoskeletal ultrasonography, this article reviews the basic physics underlying ultrasonography, its advantages and disadvantages compared with other imaging methods, and common clinical applications.

CLASSIC TECHNOLOGY MAKING A RESURGENCE

The first reports of the use of musculoskeletal ultrasonography appeared in the 1970s for investigating the rotator cuff,^1–3 actually preceding reports of its use in obstetrics and gynecology.⁴ In the 1980s, reports emerged for evaluating the Achilles tendon.^5,6 After that, its popularity in the United States plateaued, likely because of the advent of MRI, lower reimbursement and greater variability in interpretation compared with MRI, as well as a lack of physicians and sonographers trained in its use.^7,8

Musculoskeletal ultrasonography is currently experiencing a resurgence. Although it remains a specialized service more commonly available in large hospitals, its use is increasing rapidly, and it will likely become more widely available.

SPECIAL TRAINING REQUIRED

Musculoskeletal ultrasonography is simply an ultrasonographic examination of part of the musculoskeletal system. But because not all ultrasonographic transducers offer sufficient resolution for musculoskeletal evaluation and not all sonographers and imaging physicians are familiar with the specialized techniques, musculoskeletal ultrasonography often has a separate designation (eg, “MSKUS,” “MSUS”). At Cleveland Clinic, it is offered through the department of musculoskeletal imaging by subspecialty-trained musculoskeletal radiologists and specially trained musculoskeletal ultrasonographers with 4 to 5 years of training in the technique.

Musculoskeletal ultrasonography is also performed by physician groups with specialized training, including sports medicine physicians, rheumatologists, physiatrists, neurologists, and orthopedic surgeons. The American Institute of Ultrasound in Medicine offers voluntary accreditation for practice groups using musculoskeletal ultrasonography. Certification in musculoskeletal radiology is offered to sonographers through the American Registry for Diagnostic Medical Sonography.

SONOGRAPHY HAS UNIQUE QUALITIES

Ultrasonography uses high-frequency sound waves to generate images. The transducer (or probe) emits sound from the many piezoelectric elements at its surface, and the sound waves travel through and react with tissues. Sound reflected by tissues is detected by the transducer and converted to an image. Objects that reflect sound appear hyperechoic (brighter), whereas tissues that reflect little or no sound appear hypoechoic.

High-resolution imaging of superficial structures

Ultrasonography involves a fundamental trade-off between image resolution and imaging depth. Higher-frequency sound waves do not penetrate far into tissues but generate a higher-resolution image; lower-frequency sound waves can penetrate much further but yield a lower-resolution image. Although high-resolution imaging of deep structures with ultrasonography is not possible (Figure 1), many musculoskeletal structures are located superficially and are amenable to ultrasonographic evaluation.

Be aware of artifacts

Some materials attenuate sound very little, such as simple fluid. Low attenuation results in artifacts on ultrasonography, making tissues behind the simple fluid appear brighter than neighboring tissues. These artifacts may be reported as “increased through transmission” or “posterior acoustic enhancement.” Conversely, metal and bone reflect all sound waves that reach them, rendering any structures beyond them invisible. This “shadowing” creates a problem for imaging of structures in or near bone. Subcutaneous fat also attenuates sound waves, limiting the use of ultrasonography for patients with obesity (Figure 2).

High-frequency linear transducer sharpens images

High-frequency linear transducers reduce anisotropy because their flat surface keeps sound waves more uniformly perpendicular to the structure of interest.^4,7 Their development has allowed imaging of superficial structures that is superior to that of MRI. A high-frequency linear transducer offers more than twice the spatial resolution of a typical 1.5T MRI examination of superficial tissue.^12,13

Operator experience is critical

Ultrasonography examinations, more than other imaging tests, are dependent on operator experience. A solid understanding of musculoskeletal anatomy is imperative. Because the probe images only a thin section of tissue (about the thickness of a credit card), referencing adjacent structures for orientation is more difficult with ultrasonography than with CT or MRI.

The accuracy of ultrasonography is highly dependent on acquiring and interpreting images, whereas the accuracy of MRI is dependent primarily on image interpretation.⁷ Interpreting physicians must check that sonographers capture relevant targets.

Ultrasonography has multiple advantages:

No ionizing radiation exposure.

Portability. Unlike CT or MRI, ultrasonography equipment is portable.

Increased patient comfort. Patient positioning for an ultrasonography examination is more flexible than for MRI or CT,¹⁴ and the examination does not induce claustrophobia.⁸

High-resolution imaging. Ultrasonography provides very-high-resolution imaging of superficial soft tissues—in some cases, higher than MRI or CT.

Real-time dynamic examinations are possible with ultrasonography, unlike with CT or MRI, and may increase test sensitivity.^4,15–18

Implanted hardware is less of a problem. Although ultrasonography cannot image beyond implanted orthopedic metallic hardware, the hardware does not obscure surrounding soft tissues as it does on CT and MRI.^6,19,20 Also, ultrasonography is safe for patients with a pacemaker.⁸

WEAKNESSES

The main disadvantages of musculoskeletal ultrasonography are inherent to its limited field of view, making it inappropriate for a survey examination (eg, for ankle pain, knee pain,  hip pain).⁴ Unlike CT and MRI, ultrasonography does not provide a “bird’s-eye view,” and important abnormalities can be missed during evaluation of large areas (Figure 4).

Ultrasonography also cannot evaluate bone or intra-articular structures such as cartilage, bone marrow, labrum, and intra-articular ligaments; MRI is the standard for evaluating these structures.²¹

Ultrasonography is time-consuming. To perform a detailed examination of the anterior, posterior, medial, and lateral aspects of the hip, knee, or ankle would require 1.5 to 2 hours of scanning time and an additional 10 to 25 minutes of image checking and interpretation.

CURRENT CLINICAL INDICATIONS

Musculoskeletal ultrasonography is best used for clinical questions regarding limited, superficial musculoskeletal problems.

Fluid collections

Ultrasonography can help evaluate small fluid collections in soft tissue. As is true for a lung opacity on chest radiography, soft-tissue fluid detected on ultrasonography is nonspecific, and results must be correlated with the clinical picture to narrow the differential diagnosis.

Fluid collections can be classified as loculated or nonloculated.

Nonloculated fluid involves more fluid than is simply interposed between tissue planes and has no wall or defined margins. It can be simple or complex in appearance: simple fluid is anechoic, and complex fluid appears more heterogeneous and may contain septations or debris.

Subcutaneous edema, which may occur postoperatively or from trauma, venous insufficiency, or inflammatory or infectious processes, appears on ultrasonography as nonloculated fluid interspersed between subcutaneous fat lobules.

Loculated fluid collections have well-defined margins or a discrete wall that does not follow normal tissue planes. They can also be simple or complex and can be caused by hematoma, abscess, or ganglion. Less commonly, neoplasms can mimic a loculated fluid collection (Figure 4).

A ganglion is a specific type of loculated fluid collection containing synovial fluid arising from a joint or tendon sheath. It tends to occur in specific locations, most commonly around the wrist, most often arising from the dorsal scapholunate ligament and volar wrist between the radial artery and flexor carpi radialis.²² On MRI, it can be difficult to distinguish between small vascular structures and a small ganglion, especially in the hands and feet.²³

Ultrasonography can also help identify a  Baker cyst, a specific fluid collection arising from the semimembranosus bursa between the medial head of the gastrocnemius tendon and the semimembranosus tendon. Ultrasonography can also detect inflammation, rupture, or leaking associated with a Baker cyst.²⁴

Power Doppler is an ultrasonographic examination that can detect increased blood flow surrounding a fluid collection and determine the likelihood of an acute inflammatory or infectious cause.²⁵

Joint effusion and synovitis

Musculoskeletal ultrasonography can help evaluate joints for effusion and synovitis. It is highly sensitive (94%) and specific (95%) for synovitis, making it superior to contrast-enhanced MRI.^26,27 The area of concern should be limited to 1 quadrant of a joint (anterior, posterior, medial, or lateral); for problems beyond that, MRI should be considered.

A joint effusion appears as a distended joint capsule containing hypoechoic (complex) or anechoic (simple) joint fluid.

Complex joint fluid may contain debris and occurs with hemarthrosis, infection, and inflammation.²³ Hypertrophied synovium is hypoechoic and can mimic complex joint fluid.

Power Doppler evaluation can help distinguish synovitis from joint fluid by demonstrating blood flow, a feature of synovitis but not of simple joint fluid. Power Doppler is the most sensitive means of detecting blood flow, although it does not show direction of flow.²⁸

Using ultrasonography can help to improve disease control and minimize disabling changes by monitoring synovitis therapy. In addition, subclinical synovitis and enthesitis (inflammation of insertion sites of tendons or ligaments into bone) detected by ultrasonography may predict future disease and disease flares.^29–31

Ultrasonographic guidance for a wide range of procedures is increasing rapidly.^32–36 Multiple studies have shown the advantage of ultrasonography-guided aspiration and injection compared with techniques without imaging guidance.^37,38

Soft-tissue masses

Accurately diagnosing soft-tissue masses can be difficult. A mass may remain indeterminate even after multiple imaging studies, requiring biopsy or surgical referral. However, for a few specific masses, ultrasonography is highly accurate and can eliminate the need for further imaging.

Ultrasonography can help evaluate soft- tissue masses no larger than 5 cm in diameter and no deeper than superficial muscular fascia. If the mass is larger or deeper than that, ultrasonography is less reliable for showing the margins of the mass and its relationship to adjacent structures (Figure 5). Further imaging by MRI may be recommended in such cases.

Fortunately, many of the most common soft-tissue masses can be accurately diagnosed with ultrasonography, including lipomas, ganglion cysts, foreign bodies, and simple fluid collections.^4,39 Nerve-sheath tumors can also be diagnosed with ultrasonography if the lesion clearly arises from a nerve. Other soft-tissue masses are likely to be indeterminate with ultrasonography, requiring follow-up with MRI with contrast.

Musculoskeletal ultrasonography can be effective for evaluating tendons around joints, especially 1 or a small number of nearby superficial tendons. Tendons particularly well suited for ultrasonographic examination include:

• Upper-extremity tendons located in the rotator cuff or around the elbow, and flexor and extensor tendons of the hands; ultrasonographic evaluation of the rotator cuff is highly accurate, equivalent to that of MRI for partial-thickness and full-thickness tearing^40–43
• Lower-extremity tendons of the extensor mechanism of the knee, distal hamstring tendons, tendons around the ankle,^44–46 and flexor and extensor tendons of the foot.

Ultrasonography can help diagnose a variety of tendon abnormalities (Table 1),^48,49 including tearing, for which a dynamic examination can be performed.

Many tendons have a tendon sheath containing tenosynovium, while others have surrounding peritenon only; either can become thickened and inflamed. Tenosynovitis is a nonspecific finding and may be inflammatory, infectious, or posttraumatic. The presence of tendon sheath fluid alone on ultrasonography can be a normal finding, and some tendon sheaths that communicate with adjacent joints (eg, the long head biceps tendon, the flexor hallucis longus tendon) commonly contain simple fluid.⁶ A dynamic examination with ultrasonography can help diagnose snapping related to abnormal tendon movement, for example, in the case of intra-sheath and extra-sheath subluxation of the peroneal tendons.^45,50,51

Ligaments

Ultrasonography can detect abnormalities in many superficial ligaments (Table 1).

Ankle. Ankle ligaments are superficial and can be clearly visualized. The diagnostic accuracy of ultrasonography for tearing of the anterior talofibular ligament may be as high as 100%.^50,52,53

Elbow and thumb. The larger of the collateral ligaments of the elbow, especially the ulnar collateral ligament, and the ulnar collateral ligament of the thumb can be effectively evaluated with ultrasonography.^54,55

Knee. The collateral ligaments of the knee can be seen with ultrasonography, but injuries of the external ligaments of the knee are often associated with intrinsic derangements that cannot be evaluated with ultrasonography.^56,57 Intra-articular ligaments such as the anterior cruciate ligament are also not amenable to ultrasonography.

Dynamic examination of a ligament with ultrasonography can help determine the grade of the injury.

Deeply located ligaments (eg, around the hip) and ligaments surrounded by bone, such as the Lisfranc ligament, cannot be completely seen on ultrasonography.

Muscle

Musculoskeletal ultrasonography is useful for small areas of concern within a muscle (Table 1). It can detect muscle strains and tears, intramuscular collections or lesions, and fascial scarring or fascial injuries such as superficial muscle herniation. Although ultrasonography may yield a definitive diagnosis for a muscle problem, further imaging may be needed.

Nerves

Ultrasonography is useful for peripheral nerve investigation but requires a steep learning curve for sonographers and interpreting physicians.^58,59 It is best suited for directed questions regarding focal abnormal nerve findings on physical examination.

Ultrasonography can help identify areas of nerve entrapment caused by a mass or dynamic compression. It can detect neuritis (Table 1), lesions of peripheral nerves (eg, nerve-sheath tumors), and neuromas (eg, Morton neuroma of the intermetatarsal space). In a large meta-analysis, ultrasonography and MRI were found to be equally accurate for detecting Morton neuroma.⁶⁰ Even for nerve-sheath tumors located deep to the muscular fascia, ultrasonography can confirm the diagnosis because of the characteristic appearance of the nerves. Ultrasonography can also demonstrate a large extent of the course of superficial peripheral nerves while keeping the imaging plane appropriately oriented to the nerves.

Acknowledgment: We would like to sincerely thank Megan Griffiths, MA, for her help in the preparation and submission of this manuscript.

Ultrasonography has been used to evaluate musculoskeletal problems for decades but has only recently become more widely available in the United States. Advances in technology and physician familiarity are increasing its role in orthopedic imaging.

See related editorial

No single imaging method can yield all musculoskeletal diagnoses. Like any imaging technique, ultrasonography has strengths and weaknesses specific to orthopedics. Radiography, computed tomography (CT), and magnetic resonance imaging (MRI) play important roles for investigating musculoskeletal problems and are complementary to each other and to ultrasonography.

To help clinicians make informed decisions about ordering musculoskeletal ultrasonography, this article reviews the basic physics underlying ultrasonography, its advantages and disadvantages compared with other imaging methods, and common clinical applications.

CLASSIC TECHNOLOGY MAKING A RESURGENCE

The first reports of the use of musculoskeletal ultrasonography appeared in the 1970s for investigating the rotator cuff,^1–3 actually preceding reports of its use in obstetrics and gynecology.⁴ In the 1980s, reports emerged for evaluating the Achilles tendon.^5,6 After that, its popularity in the United States plateaued, likely because of the advent of MRI, lower reimbursement and greater variability in interpretation compared with MRI, as well as a lack of physicians and sonographers trained in its use.^7,8

Musculoskeletal ultrasonography is currently experiencing a resurgence. Although it remains a specialized service more commonly available in large hospitals, its use is increasing rapidly, and it will likely become more widely available.

SPECIAL TRAINING REQUIRED

Musculoskeletal ultrasonography is simply an ultrasonographic examination of part of the musculoskeletal system. But because not all ultrasonographic transducers offer sufficient resolution for musculoskeletal evaluation and not all sonographers and imaging physicians are familiar with the specialized techniques, musculoskeletal ultrasonography often has a separate designation (eg, “MSKUS,” “MSUS”). At Cleveland Clinic, it is offered through the department of musculoskeletal imaging by subspecialty-trained musculoskeletal radiologists and specially trained musculoskeletal ultrasonographers with 4 to 5 years of training in the technique.

Musculoskeletal ultrasonography is also performed by physician groups with specialized training, including sports medicine physicians, rheumatologists, physiatrists, neurologists, and orthopedic surgeons. The American Institute of Ultrasound in Medicine offers voluntary accreditation for practice groups using musculoskeletal ultrasonography. Certification in musculoskeletal radiology is offered to sonographers through the American Registry for Diagnostic Medical Sonography.

SONOGRAPHY HAS UNIQUE QUALITIES

Ultrasonography uses high-frequency sound waves to generate images. The transducer (or probe) emits sound from the many piezoelectric elements at its surface, and the sound waves travel through and react with tissues. Sound reflected by tissues is detected by the transducer and converted to an image. Objects that reflect sound appear hyperechoic (brighter), whereas tissues that reflect little or no sound appear hypoechoic.

High-resolution imaging of superficial structures

Ultrasonography involves a fundamental trade-off between image resolution and imaging depth. Higher-frequency sound waves do not penetrate far into tissues but generate a higher-resolution image; lower-frequency sound waves can penetrate much further but yield a lower-resolution image. Although high-resolution imaging of deep structures with ultrasonography is not possible (Figure 1), many musculoskeletal structures are located superficially and are amenable to ultrasonographic evaluation.

Be aware of artifacts

Some materials attenuate sound very little, such as simple fluid. Low attenuation results in artifacts on ultrasonography, making tissues behind the simple fluid appear brighter than neighboring tissues. These artifacts may be reported as “increased through transmission” or “posterior acoustic enhancement.” Conversely, metal and bone reflect all sound waves that reach them, rendering any structures beyond them invisible. This “shadowing” creates a problem for imaging of structures in or near bone. Subcutaneous fat also attenuates sound waves, limiting the use of ultrasonography for patients with obesity (Figure 2).

High-frequency linear transducer sharpens images

High-frequency linear transducers reduce anisotropy because their flat surface keeps sound waves more uniformly perpendicular to the structure of interest.^4,7 Their development has allowed imaging of superficial structures that is superior to that of MRI. A high-frequency linear transducer offers more than twice the spatial resolution of a typical 1.5T MRI examination of superficial tissue.^12,13

Operator experience is critical

Ultrasonography examinations, more than other imaging tests, are dependent on operator experience. A solid understanding of musculoskeletal anatomy is imperative. Because the probe images only a thin section of tissue (about the thickness of a credit card), referencing adjacent structures for orientation is more difficult with ultrasonography than with CT or MRI.

The accuracy of ultrasonography is highly dependent on acquiring and interpreting images, whereas the accuracy of MRI is dependent primarily on image interpretation.⁷ Interpreting physicians must check that sonographers capture relevant targets.

Ultrasonography has multiple advantages:

No ionizing radiation exposure.

Portability. Unlike CT or MRI, ultrasonography equipment is portable.

Increased patient comfort. Patient positioning for an ultrasonography examination is more flexible than for MRI or CT,¹⁴ and the examination does not induce claustrophobia.⁸

High-resolution imaging. Ultrasonography provides very-high-resolution imaging of superficial soft tissues—in some cases, higher than MRI or CT.

Real-time dynamic examinations are possible with ultrasonography, unlike with CT or MRI, and may increase test sensitivity.^4,15–18

Implanted hardware is less of a problem. Although ultrasonography cannot image beyond implanted orthopedic metallic hardware, the hardware does not obscure surrounding soft tissues as it does on CT and MRI.^6,19,20 Also, ultrasonography is safe for patients with a pacemaker.⁸

WEAKNESSES

The main disadvantages of musculoskeletal ultrasonography are inherent to its limited field of view, making it inappropriate for a survey examination (eg, for ankle pain, knee pain,  hip pain).⁴ Unlike CT and MRI, ultrasonography does not provide a “bird’s-eye view,” and important abnormalities can be missed during evaluation of large areas (Figure 4).

Ultrasonography also cannot evaluate bone or intra-articular structures such as cartilage, bone marrow, labrum, and intra-articular ligaments; MRI is the standard for evaluating these structures.²¹

Ultrasonography is time-consuming. To perform a detailed examination of the anterior, posterior, medial, and lateral aspects of the hip, knee, or ankle would require 1.5 to 2 hours of scanning time and an additional 10 to 25 minutes of image checking and interpretation.

CURRENT CLINICAL INDICATIONS

Musculoskeletal ultrasonography is best used for clinical questions regarding limited, superficial musculoskeletal problems.

Fluid collections

Ultrasonography can help evaluate small fluid collections in soft tissue. As is true for a lung opacity on chest radiography, soft-tissue fluid detected on ultrasonography is nonspecific, and results must be correlated with the clinical picture to narrow the differential diagnosis.

Fluid collections can be classified as loculated or nonloculated.

Nonloculated fluid involves more fluid than is simply interposed between tissue planes and has no wall or defined margins. It can be simple or complex in appearance: simple fluid is anechoic, and complex fluid appears more heterogeneous and may contain septations or debris.

Subcutaneous edema, which may occur postoperatively or from trauma, venous insufficiency, or inflammatory or infectious processes, appears on ultrasonography as nonloculated fluid interspersed between subcutaneous fat lobules.

Loculated fluid collections have well-defined margins or a discrete wall that does not follow normal tissue planes. They can also be simple or complex and can be caused by hematoma, abscess, or ganglion. Less commonly, neoplasms can mimic a loculated fluid collection (Figure 4).

A ganglion is a specific type of loculated fluid collection containing synovial fluid arising from a joint or tendon sheath. It tends to occur in specific locations, most commonly around the wrist, most often arising from the dorsal scapholunate ligament and volar wrist between the radial artery and flexor carpi radialis.²² On MRI, it can be difficult to distinguish between small vascular structures and a small ganglion, especially in the hands and feet.²³

Ultrasonography can also help identify a  Baker cyst, a specific fluid collection arising from the semimembranosus bursa between the medial head of the gastrocnemius tendon and the semimembranosus tendon. Ultrasonography can also detect inflammation, rupture, or leaking associated with a Baker cyst.²⁴

Power Doppler is an ultrasonographic examination that can detect increased blood flow surrounding a fluid collection and determine the likelihood of an acute inflammatory or infectious cause.²⁵

Joint effusion and synovitis

Musculoskeletal ultrasonography can help evaluate joints for effusion and synovitis. It is highly sensitive (94%) and specific (95%) for synovitis, making it superior to contrast-enhanced MRI.^26,27 The area of concern should be limited to 1 quadrant of a joint (anterior, posterior, medial, or lateral); for problems beyond that, MRI should be considered.

A joint effusion appears as a distended joint capsule containing hypoechoic (complex) or anechoic (simple) joint fluid.

Complex joint fluid may contain debris and occurs with hemarthrosis, infection, and inflammation.²³ Hypertrophied synovium is hypoechoic and can mimic complex joint fluid.

Power Doppler evaluation can help distinguish synovitis from joint fluid by demonstrating blood flow, a feature of synovitis but not of simple joint fluid. Power Doppler is the most sensitive means of detecting blood flow, although it does not show direction of flow.²⁸

Using ultrasonography can help to improve disease control and minimize disabling changes by monitoring synovitis therapy. In addition, subclinical synovitis and enthesitis (inflammation of insertion sites of tendons or ligaments into bone) detected by ultrasonography may predict future disease and disease flares.^29–31

Ultrasonographic guidance for a wide range of procedures is increasing rapidly.^32–36 Multiple studies have shown the advantage of ultrasonography-guided aspiration and injection compared with techniques without imaging guidance.^37,38

Soft-tissue masses

Accurately diagnosing soft-tissue masses can be difficult. A mass may remain indeterminate even after multiple imaging studies, requiring biopsy or surgical referral. However, for a few specific masses, ultrasonography is highly accurate and can eliminate the need for further imaging.

Ultrasonography can help evaluate soft- tissue masses no larger than 5 cm in diameter and no deeper than superficial muscular fascia. If the mass is larger or deeper than that, ultrasonography is less reliable for showing the margins of the mass and its relationship to adjacent structures (Figure 5). Further imaging by MRI may be recommended in such cases.

Fortunately, many of the most common soft-tissue masses can be accurately diagnosed with ultrasonography, including lipomas, ganglion cysts, foreign bodies, and simple fluid collections.^4,39 Nerve-sheath tumors can also be diagnosed with ultrasonography if the lesion clearly arises from a nerve. Other soft-tissue masses are likely to be indeterminate with ultrasonography, requiring follow-up with MRI with contrast.

Musculoskeletal ultrasonography can be effective for evaluating tendons around joints, especially 1 or a small number of nearby superficial tendons. Tendons particularly well suited for ultrasonographic examination include:

• Upper-extremity tendons located in the rotator cuff or around the elbow, and flexor and extensor tendons of the hands; ultrasonographic evaluation of the rotator cuff is highly accurate, equivalent to that of MRI for partial-thickness and full-thickness tearing^40–43
• Lower-extremity tendons of the extensor mechanism of the knee, distal hamstring tendons, tendons around the ankle,^44–46 and flexor and extensor tendons of the foot.

Ultrasonography can help diagnose a variety of tendon abnormalities (Table 1),^48,49 including tearing, for which a dynamic examination can be performed.

Many tendons have a tendon sheath containing tenosynovium, while others have surrounding peritenon only; either can become thickened and inflamed. Tenosynovitis is a nonspecific finding and may be inflammatory, infectious, or posttraumatic. The presence of tendon sheath fluid alone on ultrasonography can be a normal finding, and some tendon sheaths that communicate with adjacent joints (eg, the long head biceps tendon, the flexor hallucis longus tendon) commonly contain simple fluid.⁶ A dynamic examination with ultrasonography can help diagnose snapping related to abnormal tendon movement, for example, in the case of intra-sheath and extra-sheath subluxation of the peroneal tendons.^45,50,51

Ligaments

Ultrasonography can detect abnormalities in many superficial ligaments (Table 1).

Ankle. Ankle ligaments are superficial and can be clearly visualized. The diagnostic accuracy of ultrasonography for tearing of the anterior talofibular ligament may be as high as 100%.^50,52,53

Elbow and thumb. The larger of the collateral ligaments of the elbow, especially the ulnar collateral ligament, and the ulnar collateral ligament of the thumb can be effectively evaluated with ultrasonography.^54,55

Knee. The collateral ligaments of the knee can be seen with ultrasonography, but injuries of the external ligaments of the knee are often associated with intrinsic derangements that cannot be evaluated with ultrasonography.^56,57 Intra-articular ligaments such as the anterior cruciate ligament are also not amenable to ultrasonography.

Dynamic examination of a ligament with ultrasonography can help determine the grade of the injury.

Deeply located ligaments (eg, around the hip) and ligaments surrounded by bone, such as the Lisfranc ligament, cannot be completely seen on ultrasonography.

Muscle

Musculoskeletal ultrasonography is useful for small areas of concern within a muscle (Table 1). It can detect muscle strains and tears, intramuscular collections or lesions, and fascial scarring or fascial injuries such as superficial muscle herniation. Although ultrasonography may yield a definitive diagnosis for a muscle problem, further imaging may be needed.

Nerves

Ultrasonography is useful for peripheral nerve investigation but requires a steep learning curve for sonographers and interpreting physicians.^58,59 It is best suited for directed questions regarding focal abnormal nerve findings on physical examination.

Ultrasonography can help identify areas of nerve entrapment caused by a mass or dynamic compression. It can detect neuritis (Table 1), lesions of peripheral nerves (eg, nerve-sheath tumors), and neuromas (eg, Morton neuroma of the intermetatarsal space). In a large meta-analysis, ultrasonography and MRI were found to be equally accurate for detecting Morton neuroma.⁶⁰ Even for nerve-sheath tumors located deep to the muscular fascia, ultrasonography can confirm the diagnosis because of the characteristic appearance of the nerves. Ultrasonography can also demonstrate a large extent of the course of superficial peripheral nerves while keeping the imaging plane appropriately oriented to the nerves.

Acknowledgment: We would like to sincerely thank Megan Griffiths, MA, for her help in the preparation and submission of this manuscript.

Ultrasonography has been used to evaluate musculoskeletal problems for decades but has only recently become more widely available in the United States. Advances in technology and physician familiarity are increasing its role in orthopedic imaging.

See related editorial

No single imaging method can yield all musculoskeletal diagnoses. Like any imaging technique, ultrasonography has strengths and weaknesses specific to orthopedics. Radiography, computed tomography (CT), and magnetic resonance imaging (MRI) play important roles for investigating musculoskeletal problems and are complementary to each other and to ultrasonography.

To help clinicians make informed decisions about ordering musculoskeletal ultrasonography, this article reviews the basic physics underlying ultrasonography, its advantages and disadvantages compared with other imaging methods, and common clinical applications.

CLASSIC TECHNOLOGY MAKING A RESURGENCE

The first reports of the use of musculoskeletal ultrasonography appeared in the 1970s for investigating the rotator cuff,^1–3 actually preceding reports of its use in obstetrics and gynecology.⁴ In the 1980s, reports emerged for evaluating the Achilles tendon.^5,6 After that, its popularity in the United States plateaued, likely because of the advent of MRI, lower reimbursement and greater variability in interpretation compared with MRI, as well as a lack of physicians and sonographers trained in its use.^7,8

Musculoskeletal ultrasonography is currently experiencing a resurgence. Although it remains a specialized service more commonly available in large hospitals, its use is increasing rapidly, and it will likely become more widely available.

SPECIAL TRAINING REQUIRED

Musculoskeletal ultrasonography is simply an ultrasonographic examination of part of the musculoskeletal system. But because not all ultrasonographic transducers offer sufficient resolution for musculoskeletal evaluation and not all sonographers and imaging physicians are familiar with the specialized techniques, musculoskeletal ultrasonography often has a separate designation (eg, “MSKUS,” “MSUS”). At Cleveland Clinic, it is offered through the department of musculoskeletal imaging by subspecialty-trained musculoskeletal radiologists and specially trained musculoskeletal ultrasonographers with 4 to 5 years of training in the technique.

Musculoskeletal ultrasonography is also performed by physician groups with specialized training, including sports medicine physicians, rheumatologists, physiatrists, neurologists, and orthopedic surgeons. The American Institute of Ultrasound in Medicine offers voluntary accreditation for practice groups using musculoskeletal ultrasonography. Certification in musculoskeletal radiology is offered to sonographers through the American Registry for Diagnostic Medical Sonography.

SONOGRAPHY HAS UNIQUE QUALITIES

Ultrasonography uses high-frequency sound waves to generate images. The transducer (or probe) emits sound from the many piezoelectric elements at its surface, and the sound waves travel through and react with tissues. Sound reflected by tissues is detected by the transducer and converted to an image. Objects that reflect sound appear hyperechoic (brighter), whereas tissues that reflect little or no sound appear hypoechoic.

High-resolution imaging of superficial structures

Ultrasonography involves a fundamental trade-off between image resolution and imaging depth. Higher-frequency sound waves do not penetrate far into tissues but generate a higher-resolution image; lower-frequency sound waves can penetrate much further but yield a lower-resolution image. Although high-resolution imaging of deep structures with ultrasonography is not possible (Figure 1), many musculoskeletal structures are located superficially and are amenable to ultrasonographic evaluation.

Be aware of artifacts

Some materials attenuate sound very little, such as simple fluid. Low attenuation results in artifacts on ultrasonography, making tissues behind the simple fluid appear brighter than neighboring tissues. These artifacts may be reported as “increased through transmission” or “posterior acoustic enhancement.” Conversely, metal and bone reflect all sound waves that reach them, rendering any structures beyond them invisible. This “shadowing” creates a problem for imaging of structures in or near bone. Subcutaneous fat also attenuates sound waves, limiting the use of ultrasonography for patients with obesity (Figure 2).

High-frequency linear transducer sharpens images

High-frequency linear transducers reduce anisotropy because their flat surface keeps sound waves more uniformly perpendicular to the structure of interest.^4,7 Their development has allowed imaging of superficial structures that is superior to that of MRI. A high-frequency linear transducer offers more than twice the spatial resolution of a typical 1.5T MRI examination of superficial tissue.^12,13

Operator experience is critical

Ultrasonography examinations, more than other imaging tests, are dependent on operator experience. A solid understanding of musculoskeletal anatomy is imperative. Because the probe images only a thin section of tissue (about the thickness of a credit card), referencing adjacent structures for orientation is more difficult with ultrasonography than with CT or MRI.

The accuracy of ultrasonography is highly dependent on acquiring and interpreting images, whereas the accuracy of MRI is dependent primarily on image interpretation.⁷ Interpreting physicians must check that sonographers capture relevant targets.

Ultrasonography has multiple advantages:

No ionizing radiation exposure.

Portability. Unlike CT or MRI, ultrasonography equipment is portable.

Increased patient comfort. Patient positioning for an ultrasonography examination is more flexible than for MRI or CT,¹⁴ and the examination does not induce claustrophobia.⁸

High-resolution imaging. Ultrasonography provides very-high-resolution imaging of superficial soft tissues—in some cases, higher than MRI or CT.

Real-time dynamic examinations are possible with ultrasonography, unlike with CT or MRI, and may increase test sensitivity.^4,15–18

Implanted hardware is less of a problem. Although ultrasonography cannot image beyond implanted orthopedic metallic hardware, the hardware does not obscure surrounding soft tissues as it does on CT and MRI.^6,19,20 Also, ultrasonography is safe for patients with a pacemaker.⁸

WEAKNESSES

The main disadvantages of musculoskeletal ultrasonography are inherent to its limited field of view, making it inappropriate for a survey examination (eg, for ankle pain, knee pain,  hip pain).⁴ Unlike CT and MRI, ultrasonography does not provide a “bird’s-eye view,” and important abnormalities can be missed during evaluation of large areas (Figure 4).

Ultrasonography also cannot evaluate bone or intra-articular structures such as cartilage, bone marrow, labrum, and intra-articular ligaments; MRI is the standard for evaluating these structures.²¹

Ultrasonography is time-consuming. To perform a detailed examination of the anterior, posterior, medial, and lateral aspects of the hip, knee, or ankle would require 1.5 to 2 hours of scanning time and an additional 10 to 25 minutes of image checking and interpretation.

CURRENT CLINICAL INDICATIONS

Musculoskeletal ultrasonography is best used for clinical questions regarding limited, superficial musculoskeletal problems.

Fluid collections

Ultrasonography can help evaluate small fluid collections in soft tissue. As is true for a lung opacity on chest radiography, soft-tissue fluid detected on ultrasonography is nonspecific, and results must be correlated with the clinical picture to narrow the differential diagnosis.

Fluid collections can be classified as loculated or nonloculated.

Nonloculated fluid involves more fluid than is simply interposed between tissue planes and has no wall or defined margins. It can be simple or complex in appearance: simple fluid is anechoic, and complex fluid appears more heterogeneous and may contain septations or debris.

Subcutaneous edema, which may occur postoperatively or from trauma, venous insufficiency, or inflammatory or infectious processes, appears on ultrasonography as nonloculated fluid interspersed between subcutaneous fat lobules.

Loculated fluid collections have well-defined margins or a discrete wall that does not follow normal tissue planes. They can also be simple or complex and can be caused by hematoma, abscess, or ganglion. Less commonly, neoplasms can mimic a loculated fluid collection (Figure 4).

A ganglion is a specific type of loculated fluid collection containing synovial fluid arising from a joint or tendon sheath. It tends to occur in specific locations, most commonly around the wrist, most often arising from the dorsal scapholunate ligament and volar wrist between the radial artery and flexor carpi radialis.²² On MRI, it can be difficult to distinguish between small vascular structures and a small ganglion, especially in the hands and feet.²³

Ultrasonography can also help identify a  Baker cyst, a specific fluid collection arising from the semimembranosus bursa between the medial head of the gastrocnemius tendon and the semimembranosus tendon. Ultrasonography can also detect inflammation, rupture, or leaking associated with a Baker cyst.²⁴

Power Doppler is an ultrasonographic examination that can detect increased blood flow surrounding a fluid collection and determine the likelihood of an acute inflammatory or infectious cause.²⁵

Joint effusion and synovitis

Musculoskeletal ultrasonography can help evaluate joints for effusion and synovitis. It is highly sensitive (94%) and specific (95%) for synovitis, making it superior to contrast-enhanced MRI.^26,27 The area of concern should be limited to 1 quadrant of a joint (anterior, posterior, medial, or lateral); for problems beyond that, MRI should be considered.

A joint effusion appears as a distended joint capsule containing hypoechoic (complex) or anechoic (simple) joint fluid.

Complex joint fluid may contain debris and occurs with hemarthrosis, infection, and inflammation.²³ Hypertrophied synovium is hypoechoic and can mimic complex joint fluid.

Power Doppler evaluation can help distinguish synovitis from joint fluid by demonstrating blood flow, a feature of synovitis but not of simple joint fluid. Power Doppler is the most sensitive means of detecting blood flow, although it does not show direction of flow.²⁸

Using ultrasonography can help to improve disease control and minimize disabling changes by monitoring synovitis therapy. In addition, subclinical synovitis and enthesitis (inflammation of insertion sites of tendons or ligaments into bone) detected by ultrasonography may predict future disease and disease flares.^29–31

Ultrasonographic guidance for a wide range of procedures is increasing rapidly.^32–36 Multiple studies have shown the advantage of ultrasonography-guided aspiration and injection compared with techniques without imaging guidance.^37,38

Soft-tissue masses

Accurately diagnosing soft-tissue masses can be difficult. A mass may remain indeterminate even after multiple imaging studies, requiring biopsy or surgical referral. However, for a few specific masses, ultrasonography is highly accurate and can eliminate the need for further imaging.

Ultrasonography can help evaluate soft- tissue masses no larger than 5 cm in diameter and no deeper than superficial muscular fascia. If the mass is larger or deeper than that, ultrasonography is less reliable for showing the margins of the mass and its relationship to adjacent structures (Figure 5). Further imaging by MRI may be recommended in such cases.

Fortunately, many of the most common soft-tissue masses can be accurately diagnosed with ultrasonography, including lipomas, ganglion cysts, foreign bodies, and simple fluid collections.^4,39 Nerve-sheath tumors can also be diagnosed with ultrasonography if the lesion clearly arises from a nerve. Other soft-tissue masses are likely to be indeterminate with ultrasonography, requiring follow-up with MRI with contrast.

Musculoskeletal ultrasonography can be effective for evaluating tendons around joints, especially 1 or a small number of nearby superficial tendons. Tendons particularly well suited for ultrasonographic examination include:

• Upper-extremity tendons located in the rotator cuff or around the elbow, and flexor and extensor tendons of the hands; ultrasonographic evaluation of the rotator cuff is highly accurate, equivalent to that of MRI for partial-thickness and full-thickness tearing^40–43
• Lower-extremity tendons of the extensor mechanism of the knee, distal hamstring tendons, tendons around the ankle,^44–46 and flexor and extensor tendons of the foot.

Ultrasonography can help diagnose a variety of tendon abnormalities (Table 1),^48,49 including tearing, for which a dynamic examination can be performed.

Many tendons have a tendon sheath containing tenosynovium, while others have surrounding peritenon only; either can become thickened and inflamed. Tenosynovitis is a nonspecific finding and may be inflammatory, infectious, or posttraumatic. The presence of tendon sheath fluid alone on ultrasonography can be a normal finding, and some tendon sheaths that communicate with adjacent joints (eg, the long head biceps tendon, the flexor hallucis longus tendon) commonly contain simple fluid.⁶ A dynamic examination with ultrasonography can help diagnose snapping related to abnormal tendon movement, for example, in the case of intra-sheath and extra-sheath subluxation of the peroneal tendons.^45,50,51

Ligaments

Ultrasonography can detect abnormalities in many superficial ligaments (Table 1).

Ankle. Ankle ligaments are superficial and can be clearly visualized. The diagnostic accuracy of ultrasonography for tearing of the anterior talofibular ligament may be as high as 100%.^50,52,53

Elbow and thumb. The larger of the collateral ligaments of the elbow, especially the ulnar collateral ligament, and the ulnar collateral ligament of the thumb can be effectively evaluated with ultrasonography.^54,55

Knee. The collateral ligaments of the knee can be seen with ultrasonography, but injuries of the external ligaments of the knee are often associated with intrinsic derangements that cannot be evaluated with ultrasonography.^56,57 Intra-articular ligaments such as the anterior cruciate ligament are also not amenable to ultrasonography.

Dynamic examination of a ligament with ultrasonography can help determine the grade of the injury.

Deeply located ligaments (eg, around the hip) and ligaments surrounded by bone, such as the Lisfranc ligament, cannot be completely seen on ultrasonography.

Muscle

Musculoskeletal ultrasonography is useful for small areas of concern within a muscle (Table 1). It can detect muscle strains and tears, intramuscular collections or lesions, and fascial scarring or fascial injuries such as superficial muscle herniation. Although ultrasonography may yield a definitive diagnosis for a muscle problem, further imaging may be needed.

Nerves

Ultrasonography is useful for peripheral nerve investigation but requires a steep learning curve for sonographers and interpreting physicians.^58,59 It is best suited for directed questions regarding focal abnormal nerve findings on physical examination.

Ultrasonography can help identify areas of nerve entrapment caused by a mass or dynamic compression. It can detect neuritis (Table 1), lesions of peripheral nerves (eg, nerve-sheath tumors), and neuromas (eg, Morton neuroma of the intermetatarsal space). In a large meta-analysis, ultrasonography and MRI were found to be equally accurate for detecting Morton neuroma.⁶⁰ Even for nerve-sheath tumors located deep to the muscular fascia, ultrasonography can confirm the diagnosis because of the characteristic appearance of the nerves. Ultrasonography can also demonstrate a large extent of the course of superficial peripheral nerves while keeping the imaging plane appropriately oriented to the nerves.

Acknowledgment: We would like to sincerely thank Megan Griffiths, MA, for her help in the preparation and submission of this manuscript.

A 50-year-old woman with hypertension   presents with a history of polyarticular small-joint pain for the last 3 months. Her pain is worse in the morning, and it affects her metacarpal, proximal, and distal phalangeal joints. She describes intermittent swelling of her hands and morning stiffness lasting 15 to 30 minutes.

See related article

Her physical examination is unremarkable, with no evidence of active inflammation (synovitis), joint tenderness, restrictions in movement, or deformity. Her description of her symptoms raises suspicion for an inflammatory arthritis, but her physical examination does not support this diagnosis.

Bedside musculoskeletal ultrasonography of her wrists reveals synovial hypertrophy, and power Doppler shows active inflammation, findings consistent with synovitis (Figure 1).
This scenario illustrates how musculoskeletal ultrasonography can prevent delayed diagnosis, thus directing the ordering of appropriate laboratory studies and allowing treatment for pain relief to be started promptly.

ULTRASONOGRAPHY HAS GAINED A SOLID ROLE

Ultrasonography has gained a solid role in the care of patients with musculoskeletal conditions.

Using obtained images, as well as power Doppler to assess inflammation, the clinician can visualize superficial anatomic structures, including the skin, muscles, joints, nerves, and the cortical layer of bone. Combining the dynamic assessment with the clinical history and findings of the physical examination makes musculoskeletal ultrasonography a powerful tool for diagnosis and management.¹

In this issue, Forney and Delzell² review the clinical use of ultrasonography of the muscles and bones and its advantages and disadvantages compared with other imaging methods. They describe its gain in popularity over the last decade and its incorporation into clinical care in multiple medical subspecialties.

Musculoskeletal ultrasonography is performed and interpreted by specially trained sonographers. It should be viewed as a complementary procedure, not as a replacement for a thorough and systematic clinical examination.³

ADVANTAGES ARE MANY

A major advantage of musculoskeletal ultrasonography over other imaging techniques is its capacity to dynamically assess joint and tendon movements⁴ and to immediately interpret them in real time.

In rheumatology, where it has made the biggest impact, it can help evaluate inflammatory and noninflammatory rheumatic diseases, assess treatment response, and guide joint injections.¹ It has been demonstrated to significantly improve timely diagnosis and management,⁵ decrease dependence on other imaging modalities, and reduce healthcare costs.⁶

With its easy portability, ultrasonography has also been integrated into orthopedics, podiatry, physical medicine and rehabilitation, sports medicine, and emergency medicine. Its role is expanding to include the assessment of the skin in systemic sclerosis, parotid and submandibular glands in Sjögren syndrome, nails in patients with psoriasis, and temporal arteries in giant cell arteritis.

A ROLE IN MEDICAL EDUCATION

Musculoskeletal ultrasonography has entered into medical education, with an increasing number of medical schools incorporating it into their curriculum over the last few years.⁷ It enhances student learning of anatomy, the physical examination, and pathologic findings of rheumatic diseases.^7,8 Some internal medicine residency programs have added ultrasonography to help identify anatomic structures for invasive procedures, increasing patient safety and reducing procedural complications.⁹

It has been incorporated into the core curriculum in many rheumatology fellowship training programs.¹⁰ Rheumatologists can now also take additional courses to enhance their skills and become certified sonographers.

Musculoskeletal ultrasonography has proven to be a useful adjunct to the physical examination. With its many advantages, it has gained acceptance and is now a mainstay in many subspecialties.

A 50-year-old woman with hypertension   presents with a history of polyarticular small-joint pain for the last 3 months. Her pain is worse in the morning, and it affects her metacarpal, proximal, and distal phalangeal joints. She describes intermittent swelling of her hands and morning stiffness lasting 15 to 30 minutes.

See related article

Her physical examination is unremarkable, with no evidence of active inflammation (synovitis), joint tenderness, restrictions in movement, or deformity. Her description of her symptoms raises suspicion for an inflammatory arthritis, but her physical examination does not support this diagnosis.

Bedside musculoskeletal ultrasonography of her wrists reveals synovial hypertrophy, and power Doppler shows active inflammation, findings consistent with synovitis (Figure 1).
This scenario illustrates how musculoskeletal ultrasonography can prevent delayed diagnosis, thus directing the ordering of appropriate laboratory studies and allowing treatment for pain relief to be started promptly.

ULTRASONOGRAPHY HAS GAINED A SOLID ROLE

Ultrasonography has gained a solid role in the care of patients with musculoskeletal conditions.

Using obtained images, as well as power Doppler to assess inflammation, the clinician can visualize superficial anatomic structures, including the skin, muscles, joints, nerves, and the cortical layer of bone. Combining the dynamic assessment with the clinical history and findings of the physical examination makes musculoskeletal ultrasonography a powerful tool for diagnosis and management.¹

In this issue, Forney and Delzell² review the clinical use of ultrasonography of the muscles and bones and its advantages and disadvantages compared with other imaging methods. They describe its gain in popularity over the last decade and its incorporation into clinical care in multiple medical subspecialties.

Musculoskeletal ultrasonography is performed and interpreted by specially trained sonographers. It should be viewed as a complementary procedure, not as a replacement for a thorough and systematic clinical examination.³

ADVANTAGES ARE MANY

A major advantage of musculoskeletal ultrasonography over other imaging techniques is its capacity to dynamically assess joint and tendon movements⁴ and to immediately interpret them in real time.

In rheumatology, where it has made the biggest impact, it can help evaluate inflammatory and noninflammatory rheumatic diseases, assess treatment response, and guide joint injections.¹ It has been demonstrated to significantly improve timely diagnosis and management,⁵ decrease dependence on other imaging modalities, and reduce healthcare costs.⁶

With its easy portability, ultrasonography has also been integrated into orthopedics, podiatry, physical medicine and rehabilitation, sports medicine, and emergency medicine. Its role is expanding to include the assessment of the skin in systemic sclerosis, parotid and submandibular glands in Sjögren syndrome, nails in patients with psoriasis, and temporal arteries in giant cell arteritis.

A ROLE IN MEDICAL EDUCATION

Musculoskeletal ultrasonography has entered into medical education, with an increasing number of medical schools incorporating it into their curriculum over the last few years.⁷ It enhances student learning of anatomy, the physical examination, and pathologic findings of rheumatic diseases.^7,8 Some internal medicine residency programs have added ultrasonography to help identify anatomic structures for invasive procedures, increasing patient safety and reducing procedural complications.⁹

It has been incorporated into the core curriculum in many rheumatology fellowship training programs.¹⁰ Rheumatologists can now also take additional courses to enhance their skills and become certified sonographers.

Musculoskeletal ultrasonography has proven to be a useful adjunct to the physical examination. With its many advantages, it has gained acceptance and is now a mainstay in many subspecialties.

A 50-year-old woman with hypertension   presents with a history of polyarticular small-joint pain for the last 3 months. Her pain is worse in the morning, and it affects her metacarpal, proximal, and distal phalangeal joints. She describes intermittent swelling of her hands and morning stiffness lasting 15 to 30 minutes.

See related article

Her physical examination is unremarkable, with no evidence of active inflammation (synovitis), joint tenderness, restrictions in movement, or deformity. Her description of her symptoms raises suspicion for an inflammatory arthritis, but her physical examination does not support this diagnosis.

Bedside musculoskeletal ultrasonography of her wrists reveals synovial hypertrophy, and power Doppler shows active inflammation, findings consistent with synovitis (Figure 1).
This scenario illustrates how musculoskeletal ultrasonography can prevent delayed diagnosis, thus directing the ordering of appropriate laboratory studies and allowing treatment for pain relief to be started promptly.

ULTRASONOGRAPHY HAS GAINED A SOLID ROLE

Ultrasonography has gained a solid role in the care of patients with musculoskeletal conditions.

Using obtained images, as well as power Doppler to assess inflammation, the clinician can visualize superficial anatomic structures, including the skin, muscles, joints, nerves, and the cortical layer of bone. Combining the dynamic assessment with the clinical history and findings of the physical examination makes musculoskeletal ultrasonography a powerful tool for diagnosis and management.¹

In this issue, Forney and Delzell² review the clinical use of ultrasonography of the muscles and bones and its advantages and disadvantages compared with other imaging methods. They describe its gain in popularity over the last decade and its incorporation into clinical care in multiple medical subspecialties.

Musculoskeletal ultrasonography is performed and interpreted by specially trained sonographers. It should be viewed as a complementary procedure, not as a replacement for a thorough and systematic clinical examination.³

ADVANTAGES ARE MANY

A major advantage of musculoskeletal ultrasonography over other imaging techniques is its capacity to dynamically assess joint and tendon movements⁴ and to immediately interpret them in real time.

In rheumatology, where it has made the biggest impact, it can help evaluate inflammatory and noninflammatory rheumatic diseases, assess treatment response, and guide joint injections.¹ It has been demonstrated to significantly improve timely diagnosis and management,⁵ decrease dependence on other imaging modalities, and reduce healthcare costs.⁶

With its easy portability, ultrasonography has also been integrated into orthopedics, podiatry, physical medicine and rehabilitation, sports medicine, and emergency medicine. Its role is expanding to include the assessment of the skin in systemic sclerosis, parotid and submandibular glands in Sjögren syndrome, nails in patients with psoriasis, and temporal arteries in giant cell arteritis.

A ROLE IN MEDICAL EDUCATION

Musculoskeletal ultrasonography has entered into medical education, with an increasing number of medical schools incorporating it into their curriculum over the last few years.⁷ It enhances student learning of anatomy, the physical examination, and pathologic findings of rheumatic diseases.^7,8 Some internal medicine residency programs have added ultrasonography to help identify anatomic structures for invasive procedures, increasing patient safety and reducing procedural complications.⁹

It has been incorporated into the core curriculum in many rheumatology fellowship training programs.¹⁰ Rheumatologists can now also take additional courses to enhance their skills and become certified sonographers.

Musculoskeletal ultrasonography has proven to be a useful adjunct to the physical examination. With its many advantages, it has gained acceptance and is now a mainstay in many subspecialties.

Case

A 23-year-old man presented to an outside hospital’s ED for evaluation of a wound on his right hand, which he sustained after he accidentally stabbed himself with a steak knife. At presentation, the patient’s vital signs were: heart rate, 90 beats/min; respiratory rate, 16 breaths/min; blood pressure, 150/92 mm Hg; and temperature, 98.1°F. Oxygen saturation was 98% on room air. Examination revealed a laceration on the patient’s right hand measuring 2 cm in length. The emergency physician (EP) closed the wound using four nylon sutures and administered a Boostrix shot. The patient was discharged home with a prescription for cephalexin capsule 500 mg to be taken four times daily for 5 days. He was instructed to return in 10 days for suture removal, but failed to follow-up.

The patient presented to our ED two months after the initial injury for evaluation of a 1.5-cm round pulsatile mass on his right palm, at the base of the middle finger, from which exuded a small amount of sanguineous fluid. The patient complained of numbness and difficulty extending his right index and middle fingers.

Discussion

Palmar Pseudoaneurysms

A pseudoaneurysm, also referred to as a traumatic aneurysm, develops when a tear of the vessel wall and hemorrhage is contained by a thin-walled capsule, typically following traumatic perforation of the arterial wall. Unlike a true aneurysm, a pseudo­aneurysm does not contain all three layers of intima, media, and adventitia. Thin walls lead to inevitable expansion over time; in some cases, a patient will present with a soft-tissue mass years after the initial injury. Compression of nearby structures can cause neuropathy, peripheral edema, venous thrombosis, arterial occlusion or emboli, and even bone erosion.^1,2

Hand pseudoaneurysms are more likely to occur on the palmar surface, involving the superficial palmar arch,³ and are due to a penetrating injury or repetitive microtrauma. Hypothenar hammer syndrome occurs when repetitive microtrauma is applied to the ulnar artery as it passes under the hook of the hamate bone into the hand. This condition is also referred to as “hammer hand syndrome” because it frequently occurs in laborers such as mechanics, carpenters, and machinists as a result of repetitive palm trauma. Cases have also been reported in baseball players and cooks who also expose their hands to repetitive trauma.³ Likewise, elderly patients who use walking canes can also present with bilateral hammer hand syndrome,³ and patients who need crutches for a prolonged period of time may also develop axillary artery aneurysms.^1,2

Although rare, there have also been cases of spontaneous hand pseudoaneurysms in patients on anticoagulation therapy;^4,5 however, pseudoaneurysms are not an absolute contraindication to initiating or continuing use of anticoagulants.

Evaluation

Physical Examination. The patient’s mass in this case was clearly pulsatile on examination, but physical examination alone is not a reliable indicator of pseudoaneurysm, as patients may present only with soft-tissue swelling, pain, erythema, or neurological symptoms.^3,6,7

Ultrasound Imaging. In the emergency setting, POC ultrasound should be performed to evaluate any soft-tissue hand mass, especially in the context of trauma or any neurovascular findings, since palmar pseudoaneurysms can easily be confused with an abscess, foreign body, cyst, or even a tendon tear.⁶ Ultrasound studies using the linear vascular probe should always be done before any attempt to incise and drain the mass.

Three ultrasound characteristics of pseudoaneurysms include expansile pulsatility, turbulent flow with a classic yin-yang sign on Doppler, and a hematoma with variable echogenicity. Variable echogenicity may represent separate episodes of bleeding and rebleeding.⁸ A “to-and-fro” spectral waveform is pathognomonic for palmar pseudoaneurysms.⁸

Computed Tomography and Magnetic Resonance Angiography. Definitive imaging for operative management includes computed tomography or magnetic resonance angiography to assess for the exact location and presence of collateral circulation.

Treatment

Treatment of pseudoaneurysms includes conservative compression therapy, surgical excision, or anastomosis, and more recently, ultrasound-guided thrombin injection (UGTI).

Compression Therapy. Compression therapy is often used for femoral artery pseudoaneurysms that develop after iatrogenic injury. However, this technique is time consuming, is uncomfortable for patients, is not effective in treating large pseudoaneurysms, and is contraindicated in patients on anticoagulation therapy. Compression therapy also has a high-failure rate of resolving pseudoaneurysms. Traditionally, surgical excision or anastomosis has been the definitive treatment for palmar pseudoaneurysms.

Ultrasound-Guided Thrombin Injection. A more recent treatment option is UGTI, which is usually performed by an interventional radiologist. Although there is no consensus on exact dose of thrombin for this procedure, the literature describes UGTI to treat both the radial and ulnar arteries.^9,10 One study of 83 pseudoaneurysms demonstrated a relationship between the size of the palmar pseudoaneurysm and the number of thrombin injections required to resolve it. Depending on the size of the palmar pseudoaneurysm, the effective thrombin doses ranged from 200 to 2,500 U. Regarding adverse effects and events from treatment, this study reported one case of transient distal ischemia.¹¹

Intravascular balloon occlusion of the pseudoaneurysm neck has also been recommended for UGTI in the femoral artery if the neck is greater than 1 mm, but there is currently nothing in the literature describing its use in palmar pseudoaneurysms.¹²

Complications

There are more descriptions of palmar, radial, and ulnar pseudoaneurysms in critical care patients due to the frequent, but necessary, use of invasive lines. Emergency physicians frequently place radial or femoral arterial lines for hemodynamic monitoring in critically ill patients. However, the incidence of pseudoaneurysms and its sequelae from these lines are not usually observed in the ED setting.

Radial arterial lines may cause thrombosis in 19% to 57% of cases, and local infection in 1% to 18% of cases.¹⁰ In a study of 12,500 patients with radial artery catheters, the rate of radial pseudoaneurysm was only 0.05%.¹¹ Although this is a small complication rate, pseudoaneurysms can lead to significant loss of function. To decrease the number of attempts and penetrating injuries to the arteries, ultrasound guidance for these procedures in the ED is strongly recommended. In addition to decreasing the risk of developing a pseudoaneurysm, ultrasound-guidance decreases the discomfort level of the patient and reduces the risk of bleeding, hematoma formation, and infection. Arterial line placement in the ED using ultrasound guidance decreases the risk of developing pseudoaneurysms and their sequelae, such as distal embolization.

Case Conclusion

The patient in this case underwent an arterial duplex study, which found a partially thrombosed right superficial palmar arch pseudoaneurysm measuring 1.91 cm x 2.08 cm, with an active flow area measuring 0.58 cm x 0.68 cm. The flow to the index finger medial artery and middle finger lateral artery was also diminished. The patient was discharged home with a bulky soft dressing and underwent excision and repair by hand surgery 3 days later. At the 1-month postoperative follow-up visit, the patient had full sensation but mildly decreased range of motion in his fingers.

Summary

Hand pseudoaneurysms are often associated with penetrating injuries—as demonstrated in our case—or repetitive microtrauma. Hand pseudoaneurysms can present with minimal findings such as isolated soft-tissue swelling, pain, or neuropathy. The EP should consider vascular pathology in the differential for patients who present with posttraumatic neuropathy. Regarding imaging studies, ultrasound is the best imaging modality to assess for pseudoaneurysms, and EPs should have a low threshold for its use at bedside—especially prior to attempting any invasive procedure. Patients with a confirmed pseudoaneurysm should be referred to a hand or vascular surgeon for surgical repair, or to an interventional radiologist for UGTI.

Case

A 23-year-old man presented to an outside hospital’s ED for evaluation of a wound on his right hand, which he sustained after he accidentally stabbed himself with a steak knife. At presentation, the patient’s vital signs were: heart rate, 90 beats/min; respiratory rate, 16 breaths/min; blood pressure, 150/92 mm Hg; and temperature, 98.1°F. Oxygen saturation was 98% on room air. Examination revealed a laceration on the patient’s right hand measuring 2 cm in length. The emergency physician (EP) closed the wound using four nylon sutures and administered a Boostrix shot. The patient was discharged home with a prescription for cephalexin capsule 500 mg to be taken four times daily for 5 days. He was instructed to return in 10 days for suture removal, but failed to follow-up.

The patient presented to our ED two months after the initial injury for evaluation of a 1.5-cm round pulsatile mass on his right palm, at the base of the middle finger, from which exuded a small amount of sanguineous fluid. The patient complained of numbness and difficulty extending his right index and middle fingers.

Discussion

Palmar Pseudoaneurysms

A pseudoaneurysm, also referred to as a traumatic aneurysm, develops when a tear of the vessel wall and hemorrhage is contained by a thin-walled capsule, typically following traumatic perforation of the arterial wall. Unlike a true aneurysm, a pseudo­aneurysm does not contain all three layers of intima, media, and adventitia. Thin walls lead to inevitable expansion over time; in some cases, a patient will present with a soft-tissue mass years after the initial injury. Compression of nearby structures can cause neuropathy, peripheral edema, venous thrombosis, arterial occlusion or emboli, and even bone erosion.^1,2

Hand pseudoaneurysms are more likely to occur on the palmar surface, involving the superficial palmar arch,³ and are due to a penetrating injury or repetitive microtrauma. Hypothenar hammer syndrome occurs when repetitive microtrauma is applied to the ulnar artery as it passes under the hook of the hamate bone into the hand. This condition is also referred to as “hammer hand syndrome” because it frequently occurs in laborers such as mechanics, carpenters, and machinists as a result of repetitive palm trauma. Cases have also been reported in baseball players and cooks who also expose their hands to repetitive trauma.³ Likewise, elderly patients who use walking canes can also present with bilateral hammer hand syndrome,³ and patients who need crutches for a prolonged period of time may also develop axillary artery aneurysms.^1,2

Although rare, there have also been cases of spontaneous hand pseudoaneurysms in patients on anticoagulation therapy;^4,5 however, pseudoaneurysms are not an absolute contraindication to initiating or continuing use of anticoagulants.

Evaluation

Physical Examination. The patient’s mass in this case was clearly pulsatile on examination, but physical examination alone is not a reliable indicator of pseudoaneurysm, as patients may present only with soft-tissue swelling, pain, erythema, or neurological symptoms.^3,6,7

Ultrasound Imaging. In the emergency setting, POC ultrasound should be performed to evaluate any soft-tissue hand mass, especially in the context of trauma or any neurovascular findings, since palmar pseudoaneurysms can easily be confused with an abscess, foreign body, cyst, or even a tendon tear.⁶ Ultrasound studies using the linear vascular probe should always be done before any attempt to incise and drain the mass.

Three ultrasound characteristics of pseudoaneurysms include expansile pulsatility, turbulent flow with a classic yin-yang sign on Doppler, and a hematoma with variable echogenicity. Variable echogenicity may represent separate episodes of bleeding and rebleeding.⁸ A “to-and-fro” spectral waveform is pathognomonic for palmar pseudoaneurysms.⁸

Computed Tomography and Magnetic Resonance Angiography. Definitive imaging for operative management includes computed tomography or magnetic resonance angiography to assess for the exact location and presence of collateral circulation.

Treatment

Treatment of pseudoaneurysms includes conservative compression therapy, surgical excision, or anastomosis, and more recently, ultrasound-guided thrombin injection (UGTI).

Compression Therapy. Compression therapy is often used for femoral artery pseudoaneurysms that develop after iatrogenic injury. However, this technique is time consuming, is uncomfortable for patients, is not effective in treating large pseudoaneurysms, and is contraindicated in patients on anticoagulation therapy. Compression therapy also has a high-failure rate of resolving pseudoaneurysms. Traditionally, surgical excision or anastomosis has been the definitive treatment for palmar pseudoaneurysms.

Ultrasound-Guided Thrombin Injection. A more recent treatment option is UGTI, which is usually performed by an interventional radiologist. Although there is no consensus on exact dose of thrombin for this procedure, the literature describes UGTI to treat both the radial and ulnar arteries.^9,10 One study of 83 pseudoaneurysms demonstrated a relationship between the size of the palmar pseudoaneurysm and the number of thrombin injections required to resolve it. Depending on the size of the palmar pseudoaneurysm, the effective thrombin doses ranged from 200 to 2,500 U. Regarding adverse effects and events from treatment, this study reported one case of transient distal ischemia.¹¹

Intravascular balloon occlusion of the pseudoaneurysm neck has also been recommended for UGTI in the femoral artery if the neck is greater than 1 mm, but there is currently nothing in the literature describing its use in palmar pseudoaneurysms.¹²

Complications

There are more descriptions of palmar, radial, and ulnar pseudoaneurysms in critical care patients due to the frequent, but necessary, use of invasive lines. Emergency physicians frequently place radial or femoral arterial lines for hemodynamic monitoring in critically ill patients. However, the incidence of pseudoaneurysms and its sequelae from these lines are not usually observed in the ED setting.

Radial arterial lines may cause thrombosis in 19% to 57% of cases, and local infection in 1% to 18% of cases.¹⁰ In a study of 12,500 patients with radial artery catheters, the rate of radial pseudoaneurysm was only 0.05%.¹¹ Although this is a small complication rate, pseudoaneurysms can lead to significant loss of function. To decrease the number of attempts and penetrating injuries to the arteries, ultrasound guidance for these procedures in the ED is strongly recommended. In addition to decreasing the risk of developing a pseudoaneurysm, ultrasound-guidance decreases the discomfort level of the patient and reduces the risk of bleeding, hematoma formation, and infection. Arterial line placement in the ED using ultrasound guidance decreases the risk of developing pseudoaneurysms and their sequelae, such as distal embolization.

Case Conclusion

The patient in this case underwent an arterial duplex study, which found a partially thrombosed right superficial palmar arch pseudoaneurysm measuring 1.91 cm x 2.08 cm, with an active flow area measuring 0.58 cm x 0.68 cm. The flow to the index finger medial artery and middle finger lateral artery was also diminished. The patient was discharged home with a bulky soft dressing and underwent excision and repair by hand surgery 3 days later. At the 1-month postoperative follow-up visit, the patient had full sensation but mildly decreased range of motion in his fingers.

Summary

Hand pseudoaneurysms are often associated with penetrating injuries—as demonstrated in our case—or repetitive microtrauma. Hand pseudoaneurysms can present with minimal findings such as isolated soft-tissue swelling, pain, or neuropathy. The EP should consider vascular pathology in the differential for patients who present with posttraumatic neuropathy. Regarding imaging studies, ultrasound is the best imaging modality to assess for pseudoaneurysms, and EPs should have a low threshold for its use at bedside—especially prior to attempting any invasive procedure. Patients with a confirmed pseudoaneurysm should be referred to a hand or vascular surgeon for surgical repair, or to an interventional radiologist for UGTI.

Case

A 23-year-old man presented to an outside hospital’s ED for evaluation of a wound on his right hand, which he sustained after he accidentally stabbed himself with a steak knife. At presentation, the patient’s vital signs were: heart rate, 90 beats/min; respiratory rate, 16 breaths/min; blood pressure, 150/92 mm Hg; and temperature, 98.1°F. Oxygen saturation was 98% on room air. Examination revealed a laceration on the patient’s right hand measuring 2 cm in length. The emergency physician (EP) closed the wound using four nylon sutures and administered a Boostrix shot. The patient was discharged home with a prescription for cephalexin capsule 500 mg to be taken four times daily for 5 days. He was instructed to return in 10 days for suture removal, but failed to follow-up.

The patient presented to our ED two months after the initial injury for evaluation of a 1.5-cm round pulsatile mass on his right palm, at the base of the middle finger, from which exuded a small amount of sanguineous fluid. The patient complained of numbness and difficulty extending his right index and middle fingers.

Discussion

Palmar Pseudoaneurysms

A pseudoaneurysm, also referred to as a traumatic aneurysm, develops when a tear of the vessel wall and hemorrhage is contained by a thin-walled capsule, typically following traumatic perforation of the arterial wall. Unlike a true aneurysm, a pseudo­aneurysm does not contain all three layers of intima, media, and adventitia. Thin walls lead to inevitable expansion over time; in some cases, a patient will present with a soft-tissue mass years after the initial injury. Compression of nearby structures can cause neuropathy, peripheral edema, venous thrombosis, arterial occlusion or emboli, and even bone erosion.^1,2

Hand pseudoaneurysms are more likely to occur on the palmar surface, involving the superficial palmar arch,³ and are due to a penetrating injury or repetitive microtrauma. Hypothenar hammer syndrome occurs when repetitive microtrauma is applied to the ulnar artery as it passes under the hook of the hamate bone into the hand. This condition is also referred to as “hammer hand syndrome” because it frequently occurs in laborers such as mechanics, carpenters, and machinists as a result of repetitive palm trauma. Cases have also been reported in baseball players and cooks who also expose their hands to repetitive trauma.³ Likewise, elderly patients who use walking canes can also present with bilateral hammer hand syndrome,³ and patients who need crutches for a prolonged period of time may also develop axillary artery aneurysms.^1,2

Although rare, there have also been cases of spontaneous hand pseudoaneurysms in patients on anticoagulation therapy;^4,5 however, pseudoaneurysms are not an absolute contraindication to initiating or continuing use of anticoagulants.

Evaluation

Physical Examination. The patient’s mass in this case was clearly pulsatile on examination, but physical examination alone is not a reliable indicator of pseudoaneurysm, as patients may present only with soft-tissue swelling, pain, erythema, or neurological symptoms.^3,6,7

Ultrasound Imaging. In the emergency setting, POC ultrasound should be performed to evaluate any soft-tissue hand mass, especially in the context of trauma or any neurovascular findings, since palmar pseudoaneurysms can easily be confused with an abscess, foreign body, cyst, or even a tendon tear.⁶ Ultrasound studies using the linear vascular probe should always be done before any attempt to incise and drain the mass.

Three ultrasound characteristics of pseudoaneurysms include expansile pulsatility, turbulent flow with a classic yin-yang sign on Doppler, and a hematoma with variable echogenicity. Variable echogenicity may represent separate episodes of bleeding and rebleeding.⁸ A “to-and-fro” spectral waveform is pathognomonic for palmar pseudoaneurysms.⁸

Computed Tomography and Magnetic Resonance Angiography. Definitive imaging for operative management includes computed tomography or magnetic resonance angiography to assess for the exact location and presence of collateral circulation.

Treatment

Treatment of pseudoaneurysms includes conservative compression therapy, surgical excision, or anastomosis, and more recently, ultrasound-guided thrombin injection (UGTI).

Compression Therapy. Compression therapy is often used for femoral artery pseudoaneurysms that develop after iatrogenic injury. However, this technique is time consuming, is uncomfortable for patients, is not effective in treating large pseudoaneurysms, and is contraindicated in patients on anticoagulation therapy. Compression therapy also has a high-failure rate of resolving pseudoaneurysms. Traditionally, surgical excision or anastomosis has been the definitive treatment for palmar pseudoaneurysms.

Ultrasound-Guided Thrombin Injection. A more recent treatment option is UGTI, which is usually performed by an interventional radiologist. Although there is no consensus on exact dose of thrombin for this procedure, the literature describes UGTI to treat both the radial and ulnar arteries.^9,10 One study of 83 pseudoaneurysms demonstrated a relationship between the size of the palmar pseudoaneurysm and the number of thrombin injections required to resolve it. Depending on the size of the palmar pseudoaneurysm, the effective thrombin doses ranged from 200 to 2,500 U. Regarding adverse effects and events from treatment, this study reported one case of transient distal ischemia.¹¹

Intravascular balloon occlusion of the pseudoaneurysm neck has also been recommended for UGTI in the femoral artery if the neck is greater than 1 mm, but there is currently nothing in the literature describing its use in palmar pseudoaneurysms.¹²

Complications

There are more descriptions of palmar, radial, and ulnar pseudoaneurysms in critical care patients due to the frequent, but necessary, use of invasive lines. Emergency physicians frequently place radial or femoral arterial lines for hemodynamic monitoring in critically ill patients. However, the incidence of pseudoaneurysms and its sequelae from these lines are not usually observed in the ED setting.

Radial arterial lines may cause thrombosis in 19% to 57% of cases, and local infection in 1% to 18% of cases.¹⁰ In a study of 12,500 patients with radial artery catheters, the rate of radial pseudoaneurysm was only 0.05%.¹¹ Although this is a small complication rate, pseudoaneurysms can lead to significant loss of function. To decrease the number of attempts and penetrating injuries to the arteries, ultrasound guidance for these procedures in the ED is strongly recommended. In addition to decreasing the risk of developing a pseudoaneurysm, ultrasound-guidance decreases the discomfort level of the patient and reduces the risk of bleeding, hematoma formation, and infection. Arterial line placement in the ED using ultrasound guidance decreases the risk of developing pseudoaneurysms and their sequelae, such as distal embolization.

Case Conclusion

The patient in this case underwent an arterial duplex study, which found a partially thrombosed right superficial palmar arch pseudoaneurysm measuring 1.91 cm x 2.08 cm, with an active flow area measuring 0.58 cm x 0.68 cm. The flow to the index finger medial artery and middle finger lateral artery was also diminished. The patient was discharged home with a bulky soft dressing and underwent excision and repair by hand surgery 3 days later. At the 1-month postoperative follow-up visit, the patient had full sensation but mildly decreased range of motion in his fingers.

Summary

Hand pseudoaneurysms are often associated with penetrating injuries—as demonstrated in our case—or repetitive microtrauma. Hand pseudoaneurysms can present with minimal findings such as isolated soft-tissue swelling, pain, or neuropathy. The EP should consider vascular pathology in the differential for patients who present with posttraumatic neuropathy. Regarding imaging studies, ultrasound is the best imaging modality to assess for pseudoaneurysms, and EPs should have a low threshold for its use at bedside—especially prior to attempting any invasive procedure. Patients with a confirmed pseudoaneurysm should be referred to a hand or vascular surgeon for surgical repair, or to an interventional radiologist for UGTI.