Hypokalemic periodic paralysis: Three rare secondary causes

Periodic paralysis is a rare neuromuscular disorder, related to a defect in muscle ion channels, characterized by episodes of painless muscle weakness, which may be precipitated by heavy exercise, fasting, or high-carbohydrate meals. Hypokalemic periodic paralysis may be familial (primary) or secondary. Here, we report three cases of secondary causes of hypokalemic periodic paralysis. On evaluation, case 1 had distal renal tubular acidosis (RTA) due to Sjogren's syndrome, case 2 had drug induced proximal RTA (Fanconi's syndrome) and case 3 had thyrotoxicosis. Clinician must be aware of causes of secondary PP as recognition and diagnosis can completely prevent further attacks of periodic paralysis. Each of the above case is rare, but completely treatable if diagnosed. Low dose steroids with bicarbonate replacement in case 1, stopping tenofovir in case 2 and carbimazole therapy in case 3 prevented further attacks of periodic paralysis and cardiopulmonary complications.