Case Report: Rapidly Ascending Weakness in a 22-year-old Man

Case

A 22-year-old white man presented to the ED after waking from sleep and experiencing painless bilateral lower extremity weakness that ascended to the right upper extremity. This weakness left the patient unable to walk. He denied incontinence and was otherwise healthy with no prior history of similar symptoms. A family history of the presenting symptomatology was denied, and there was no family history of diabetes or kidney disease. The patient did state he had upper respiratory symptoms with a sore throat and runny nose 2 weeks earlier. He denied use of tobacco, alcohol, and illicit drugs.

Physical examination revealed abnormal deep tendon reflexes, absent patellar and achilles reflexes on the right side, reduced patellar and achilles reflexes of the left side, and diminished bilateral brachioradialis reflexes. Examination of the lower extremities revealed motor strength at 2/5 on the left and 1/5 on the right. His upper extremities demonstrated bilateral 4/5 motor strength. No ptosis was observed. All pulses of the extremities were normal with good capillary refill. His vital signs were: blood pressure, 131/75 mm Hg; pulse, 75 beats/minute; respiratory rate, 18 breaths/minute; and temperature, 97.2°F

Brain and cervical spine magnetic resonance imaging, computed tomography of the head, and blood cultures were ordered; the results of each were unremarkable. A lumbar puncture (LP) was attempted in the ED, but was unsuccessful due to difficulty in patient positioning secondary to profound weakness. An LP was later succesfully performed under fluoroscopy and revealed no abnormal findings. An electrocardiogram (ECG) demonstrated normal sinus rhythm with ST-segment flattening. The differential diagnosis for rapidly ascending weakness included Guillain-Barré syndrome, transverse myelitis, toxic metabolic syndromes, and myelopathies.

A basic metabolic panel showed that the patient was profoundly hypokalemic, with a potassium level of 1.9 mEq/L. After further blood analysis, mild hypomagnesemia was observed, with a level of 1.4 mEq/L. Whle in the ED, he was given 40 mEq potassium chloride intravenously (IV) and orally, and 2 g IV magnesium sulfate in the ED. The patient was evaluated by a neurologist in the ED. No respiratory compromise was present and the patient was admitted to neurology service with consultations from both nephrology and endocrinology.

Within 12 hours of starting potassium and magnesium supplementation, the patient’s potassium and magnesium levels returned to normal and his weakness concurrently subsided. The final diagnosis of the patient was hypokalemic periodic paralysis.

Discussion

Hypokalemic periodic paralysis (HPP), a rare autosomal dominant disorder with a prevalence of one in 100,000, is characterized by muscle weakness with accompanying hypokalemia. The first onset of symptoms is usually in the first or second decade of life, with a quarter of cases presenting before the age 10 years, and half before age 16 years. Being a typically-inherited autosomal dominant disorder, approximately two-thirds of cases present with a family history—unlike this patient case in which there was no family history of the disease. It is three to four times more common in men than women.

Hypokalemic periodic paralysis typically occurs upon waking from sleep or during rest following exercise. It may also be triggered by high-carbohydrate or high-salt meals, or from alcohol consumption. The muscles of the extremeties are usually affected, while those of the eyes, face, and sphincters are typically spared. If untreated, an attack can last from several hours to several days. Tendon and cutaneous reflexes can also be reduced or absent.¹ The manifestation of HPP can, at first impression, lead the differential diagnosis in the direction of the many other conditions that cause weakness of the extremities. Guillain-Barré syndrome and transverse myelitis are the more common diagnoses for which HPP can be mistaken. It is therefore important that the EP consider HPP in the differential so that an unusual presentation such as the one in this case may be diagnosed.

When presented with extraneous complications (eg, when the condition is encountered perioperatively or suffered comorbidly with similar conditions such as Guillain-Barré syndrome), HPP can be especially difficult to recognize.^2,3 Although a relatively uncommon condition, it can be potentially life-threatening if not recognized and treated appropriately. Severe hypokalemia may cause sequela such as respiratory failure and cardiac arhythmia. Thus, ECG and cardiorespiratory monitoring are essential in patients with HPP and hypokalemia as very severe hypokalemia may also cause paralysis of bulbar and cranial nerve musculature. Electocardiographic changes are common, and may include ST-segment sagging and flattening, U waves, and T-wave inversion. Other causes in patients presenting with HPP must also be considered, as hypokalemic paralysis of a sporadic nature may be associated with conditions including barium poisoning, hyperthyroidism, renal disorders, certain endocrinopathies, and gastrointestinal potassium losses.⁴

The pathogenesis of HPP is not completely understood; however, alteration in potassium regulation are well documented. Treatment of HPP includes both oral and IV potassium supplementation. Prophylaxis against recurrent attacks has been successful with various modalities including spiranolactone daily and acetazolamide.⁴ Care must be taken to consider thyrotoxic periodic paralysis, which most commonly presents in Asian men, as hyperthyroid symptoms may be subtle. Treatment focuses on reversal of the thyrotoxic state. β-Adrenergic blocking agents reduce the frequency and severity of attacks and should be started while measures to control thyrotoxicosis are being instituted.⁴

Before a diagnosis of HPP is made, other causes of hypokalemic paralysis must first be excluded.

Conclusion

This case is important because it demonstrates an unusual presentation of HPP in an emergency setting. This perspective of HPP can help the EP in recognizing and differentiating the condsition from similar disorders. 

Dr Orlik is a resident, department of emergency medicine, Akron General Medical Center, Ohio. Mr Kovacs is a student and summer research fellow, department of emergency medicine, Akron General Medical Center, Ohio. Dr Simon is the emergency medicine research director, department of emergency medicine, Akron General Medical Center, Northeast Ohio Medical University.

Case

A 22-year-old white man presented to the ED after waking from sleep and experiencing painless bilateral lower extremity weakness that ascended to the right upper extremity. This weakness left the patient unable to walk. He denied incontinence and was otherwise healthy with no prior history of similar symptoms. A family history of the presenting symptomatology was denied, and there was no family history of diabetes or kidney disease. The patient did state he had upper respiratory symptoms with a sore throat and runny nose 2 weeks earlier. He denied use of tobacco, alcohol, and illicit drugs.

Physical examination revealed abnormal deep tendon reflexes, absent patellar and achilles reflexes on the right side, reduced patellar and achilles reflexes of the left side, and diminished bilateral brachioradialis reflexes. Examination of the lower extremities revealed motor strength at 2/5 on the left and 1/5 on the right. His upper extremities demonstrated bilateral 4/5 motor strength. No ptosis was observed. All pulses of the extremities were normal with good capillary refill. His vital signs were: blood pressure, 131/75 mm Hg; pulse, 75 beats/minute; respiratory rate, 18 breaths/minute; and temperature, 97.2°F

Brain and cervical spine magnetic resonance imaging, computed tomography of the head, and blood cultures were ordered; the results of each were unremarkable. A lumbar puncture (LP) was attempted in the ED, but was unsuccessful due to difficulty in patient positioning secondary to profound weakness. An LP was later succesfully performed under fluoroscopy and revealed no abnormal findings. An electrocardiogram (ECG) demonstrated normal sinus rhythm with ST-segment flattening. The differential diagnosis for rapidly ascending weakness included Guillain-Barré syndrome, transverse myelitis, toxic metabolic syndromes, and myelopathies.

A basic metabolic panel showed that the patient was profoundly hypokalemic, with a potassium level of 1.9 mEq/L. After further blood analysis, mild hypomagnesemia was observed, with a level of 1.4 mEq/L. Whle in the ED, he was given 40 mEq potassium chloride intravenously (IV) and orally, and 2 g IV magnesium sulfate in the ED. The patient was evaluated by a neurologist in the ED. No respiratory compromise was present and the patient was admitted to neurology service with consultations from both nephrology and endocrinology.

Within 12 hours of starting potassium and magnesium supplementation, the patient’s potassium and magnesium levels returned to normal and his weakness concurrently subsided. The final diagnosis of the patient was hypokalemic periodic paralysis.

Discussion

Hypokalemic periodic paralysis (HPP), a rare autosomal dominant disorder with a prevalence of one in 100,000, is characterized by muscle weakness with accompanying hypokalemia. The first onset of symptoms is usually in the first or second decade of life, with a quarter of cases presenting before the age 10 years, and half before age 16 years. Being a typically-inherited autosomal dominant disorder, approximately two-thirds of cases present with a family history—unlike this patient case in which there was no family history of the disease. It is three to four times more common in men than women.

Hypokalemic periodic paralysis typically occurs upon waking from sleep or during rest following exercise. It may also be triggered by high-carbohydrate or high-salt meals, or from alcohol consumption. The muscles of the extremeties are usually affected, while those of the eyes, face, and sphincters are typically spared. If untreated, an attack can last from several hours to several days. Tendon and cutaneous reflexes can also be reduced or absent.¹ The manifestation of HPP can, at first impression, lead the differential diagnosis in the direction of the many other conditions that cause weakness of the extremities. Guillain-Barré syndrome and transverse myelitis are the more common diagnoses for which HPP can be mistaken. It is therefore important that the EP consider HPP in the differential so that an unusual presentation such as the one in this case may be diagnosed.

When presented with extraneous complications (eg, when the condition is encountered perioperatively or suffered comorbidly with similar conditions such as Guillain-Barré syndrome), HPP can be especially difficult to recognize.^2,3 Although a relatively uncommon condition, it can be potentially life-threatening if not recognized and treated appropriately. Severe hypokalemia may cause sequela such as respiratory failure and cardiac arhythmia. Thus, ECG and cardiorespiratory monitoring are essential in patients with HPP and hypokalemia as very severe hypokalemia may also cause paralysis of bulbar and cranial nerve musculature. Electocardiographic changes are common, and may include ST-segment sagging and flattening, U waves, and T-wave inversion. Other causes in patients presenting with HPP must also be considered, as hypokalemic paralysis of a sporadic nature may be associated with conditions including barium poisoning, hyperthyroidism, renal disorders, certain endocrinopathies, and gastrointestinal potassium losses.⁴

The pathogenesis of HPP is not completely understood; however, alteration in potassium regulation are well documented. Treatment of HPP includes both oral and IV potassium supplementation. Prophylaxis against recurrent attacks has been successful with various modalities including spiranolactone daily and acetazolamide.⁴ Care must be taken to consider thyrotoxic periodic paralysis, which most commonly presents in Asian men, as hyperthyroid symptoms may be subtle. Treatment focuses on reversal of the thyrotoxic state. β-Adrenergic blocking agents reduce the frequency and severity of attacks and should be started while measures to control thyrotoxicosis are being instituted.⁴

Before a diagnosis of HPP is made, other causes of hypokalemic paralysis must first be excluded.

Conclusion

This case is important because it demonstrates an unusual presentation of HPP in an emergency setting. This perspective of HPP can help the EP in recognizing and differentiating the condsition from similar disorders. 

Dr Orlik is a resident, department of emergency medicine, Akron General Medical Center, Ohio. Mr Kovacs is a student and summer research fellow, department of emergency medicine, Akron General Medical Center, Ohio. Dr Simon is the emergency medicine research director, department of emergency medicine, Akron General Medical Center, Northeast Ohio Medical University.

Case

A 22-year-old white man presented to the ED after waking from sleep and experiencing painless bilateral lower extremity weakness that ascended to the right upper extremity. This weakness left the patient unable to walk. He denied incontinence and was otherwise healthy with no prior history of similar symptoms. A family history of the presenting symptomatology was denied, and there was no family history of diabetes or kidney disease. The patient did state he had upper respiratory symptoms with a sore throat and runny nose 2 weeks earlier. He denied use of tobacco, alcohol, and illicit drugs.

Physical examination revealed abnormal deep tendon reflexes, absent patellar and achilles reflexes on the right side, reduced patellar and achilles reflexes of the left side, and diminished bilateral brachioradialis reflexes. Examination of the lower extremities revealed motor strength at 2/5 on the left and 1/5 on the right. His upper extremities demonstrated bilateral 4/5 motor strength. No ptosis was observed. All pulses of the extremities were normal with good capillary refill. His vital signs were: blood pressure, 131/75 mm Hg; pulse, 75 beats/minute; respiratory rate, 18 breaths/minute; and temperature, 97.2°F

Brain and cervical spine magnetic resonance imaging, computed tomography of the head, and blood cultures were ordered; the results of each were unremarkable. A lumbar puncture (LP) was attempted in the ED, but was unsuccessful due to difficulty in patient positioning secondary to profound weakness. An LP was later succesfully performed under fluoroscopy and revealed no abnormal findings. An electrocardiogram (ECG) demonstrated normal sinus rhythm with ST-segment flattening. The differential diagnosis for rapidly ascending weakness included Guillain-Barré syndrome, transverse myelitis, toxic metabolic syndromes, and myelopathies.

A basic metabolic panel showed that the patient was profoundly hypokalemic, with a potassium level of 1.9 mEq/L. After further blood analysis, mild hypomagnesemia was observed, with a level of 1.4 mEq/L. Whle in the ED, he was given 40 mEq potassium chloride intravenously (IV) and orally, and 2 g IV magnesium sulfate in the ED. The patient was evaluated by a neurologist in the ED. No respiratory compromise was present and the patient was admitted to neurology service with consultations from both nephrology and endocrinology.

Within 12 hours of starting potassium and magnesium supplementation, the patient’s potassium and magnesium levels returned to normal and his weakness concurrently subsided. The final diagnosis of the patient was hypokalemic periodic paralysis.

Discussion

Hypokalemic periodic paralysis (HPP), a rare autosomal dominant disorder with a prevalence of one in 100,000, is characterized by muscle weakness with accompanying hypokalemia. The first onset of symptoms is usually in the first or second decade of life, with a quarter of cases presenting before the age 10 years, and half before age 16 years. Being a typically-inherited autosomal dominant disorder, approximately two-thirds of cases present with a family history—unlike this patient case in which there was no family history of the disease. It is three to four times more common in men than women.

Hypokalemic periodic paralysis typically occurs upon waking from sleep or during rest following exercise. It may also be triggered by high-carbohydrate or high-salt meals, or from alcohol consumption. The muscles of the extremeties are usually affected, while those of the eyes, face, and sphincters are typically spared. If untreated, an attack can last from several hours to several days. Tendon and cutaneous reflexes can also be reduced or absent.¹ The manifestation of HPP can, at first impression, lead the differential diagnosis in the direction of the many other conditions that cause weakness of the extremities. Guillain-Barré syndrome and transverse myelitis are the more common diagnoses for which HPP can be mistaken. It is therefore important that the EP consider HPP in the differential so that an unusual presentation such as the one in this case may be diagnosed.

When presented with extraneous complications (eg, when the condition is encountered perioperatively or suffered comorbidly with similar conditions such as Guillain-Barré syndrome), HPP can be especially difficult to recognize.^2,3 Although a relatively uncommon condition, it can be potentially life-threatening if not recognized and treated appropriately. Severe hypokalemia may cause sequela such as respiratory failure and cardiac arhythmia. Thus, ECG and cardiorespiratory monitoring are essential in patients with HPP and hypokalemia as very severe hypokalemia may also cause paralysis of bulbar and cranial nerve musculature. Electocardiographic changes are common, and may include ST-segment sagging and flattening, U waves, and T-wave inversion. Other causes in patients presenting with HPP must also be considered, as hypokalemic paralysis of a sporadic nature may be associated with conditions including barium poisoning, hyperthyroidism, renal disorders, certain endocrinopathies, and gastrointestinal potassium losses.⁴

The pathogenesis of HPP is not completely understood; however, alteration in potassium regulation are well documented. Treatment of HPP includes both oral and IV potassium supplementation. Prophylaxis against recurrent attacks has been successful with various modalities including spiranolactone daily and acetazolamide.⁴ Care must be taken to consider thyrotoxic periodic paralysis, which most commonly presents in Asian men, as hyperthyroid symptoms may be subtle. Treatment focuses on reversal of the thyrotoxic state. β-Adrenergic blocking agents reduce the frequency and severity of attacks and should be started while measures to control thyrotoxicosis are being instituted.⁴

Before a diagnosis of HPP is made, other causes of hypokalemic paralysis must first be excluded.

Conclusion

This case is important because it demonstrates an unusual presentation of HPP in an emergency setting. This perspective of HPP can help the EP in recognizing and differentiating the condsition from similar disorders. 

Dr Orlik is a resident, department of emergency medicine, Akron General Medical Center, Ohio. Mr Kovacs is a student and summer research fellow, department of emergency medicine, Akron General Medical Center, Ohio. Dr Simon is the emergency medicine research director, department of emergency medicine, Akron General Medical Center, Northeast Ohio Medical University.