Thyrotoxic Periodic Paralysis: An Underdiagnosed and Under-recognized Condition

Thyrotoxic hypokalemic periodic paralysis (TPP) is a condition characterized by the triad of acute hypokalemia without total body potassium deficit, episodic muscle paralysis, and thyrotoxicosis. We describe two cases of thyrotoxic periodic paralysis who presented to our hospital with potassium values of 1.3 MeQ/l and 1.2 MeQ/l, respectively. Surprisingly, the two patients had no documented past medical history. Based on the clinical features of high heart rate, palpitations (seen in both the patients), and exophthalmos (seen in one patient), thyrotoxic periodic paralysis was suspected. A thorough laboratory workup confirmed the diagnosis of thyrotoxicosis. Beta blockers were initiated promptly, along with intravenous potassium chloride, and the patients eventually improved symptomatically. These patients were eventually diagnosed with Graves' disease and were placed on methimazole, which prevented further attacks. Thyroid periodic paralysis (TPP) is a rare clinical manifestation of hyperthyroidism. Patients present with sudden onset paralysis associated with severe hypokalemia. The presence of paralysis and hypokalemia in a patient who has a history of hyperthyroidism should prompt the physician about thyrotoxic periodic paralysis. A high index of suspicion, prompt diagnosis, and management of the condition can prevent severe complications, such as cardiac arrhythmias.