SEVERE HYPOKALEMIA AND PARALYSIS IN A 19-YEAR-OLD PATIENT

Document Type

Conference Proceeding

Publication Date

4-2-2024

Publication Title

J Am Coll Cardiol

Abstract

Background Familial hypokalemic periodic paralysis (FHPP) is a rare, autosomal-dominant neuromuscular disorder characterized by episodes of hypokalemia that cause muscle weakness and paralysis. FHPP is more common in men and symptomatic episodes are often triggered by a high carbohydrate diet, exercise, and emotional stress. Primary prevention of episodes involves potassium replacement, avoidance of hypokalemia triggers, and carbonic anhydrase inhibitors. Case A 19-year-old healthy male presented to the hospital with acute, asymmetric muscle weakness and paralysis. His vitals were normal, and he had no other symptoms. For four years, he has had monthly episodes of similar muscle weakness provoked by exercise, high carbohydrate foods, and travel. Serum studies showed hypokalemia at 1.9 mEq/L. ECG showed sinus bradycardia with U-waves and normal QTc. TSH was normal at 2.96. Renin and aldosterone were both normal. He was admitted to the hospital with cardiac monitoring while undergoing further investigations. Subsequent outpatient genetic testing revealed a pathogenic variant of the CACNA1S gene, consistent with FHPP. Decision-making Initial treatment for the patient focused on normalizing his potassium. His ECG corrected to normal sinus rhythm with normalization of his potassium. Prior to confirmation with genetic testing, other etiologies of his hypokalemia and muscle weakness were considered and included hyperaldosteronism, familial and thyrotoxic hypokalemic periodic paralysis, and Andersen-Tawil syndrome. Given his normal QTc, lack of dysmorphic features, and normal TSH, thyrotoxic hypokalemic periodic paralysis and Andersen-Tawil syndrome were less favored for his diagnosis. He was started on potassium replacement, a carbonic anhydrase inhibitor, and instructed to avoid episode triggers. Close follow-up with genetic testing and neurology were provided. Conclusion Familial hypokalemic periodic paralysis is a life-threatening neuromuscular disorder and requires prompt diagnosis to prevent severe hypokalemia, cardiac arrhythmias, and death. Ruling-out other etiologies of hypokalemic periodic paralysis is important to guide appropriate treatment.

Volume

83

Issue

13

First Page

3699

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