SUN-496 A Challenging Diagnosis of Thyrotoxic Periodic Paralysis

Abstract

Thyrotoxic Periodic Paralysis (TPP) is a rare but potentially lethal manifestation of hyperthyroidism which is characterized by muscular weakness due to intracellular shift of potassium and subsequent hypokalemia. The muscular weakness may range from mild weakness to complete flaccid paralysis. It is predominantly seen in Asian young men. Graves’ disease has been described as the most common cause of TPP. Other rare causes of hypokalemic periodic paralysis include inherited disorders and acquired cases due to drug abuse, specifically cocaine. It is important to recognize and diagnose TPP to provide appropriate treatment and prevent serious cardiopulmonary complications.A 26 year old Hispanic male with past medical history of cocaine abuse presented to the emergency department with profound lower extremity weakness since that morning. Laboratory studies on initial evaluation revealed hypokalemia. He was admitted to the intensive care unit (ICU) for IV potassium replacement and cardiac monitoring. Upon obtaining further history, the patient had suffered a similar episode of weakness and hypokalemia two months prior. At the time, he had a positive urine toxicology for cocaine. He was treated with IV potassium with resolution of his weakness and was told the reason for the episode was cocaine induced periodic paralysis. No further work up was done due to patient leaving Against Medical Advice. The patient stopped recreational drug abuse after this diagnosis.During current hospitalization, further laboratory studies revealed hyperthyroidism. TSI and TPO antibodies were elevated and thus patient was diagnosed with Graves’ disease. On questioning, patient was asymptomatic and clinically euthyroid. He was treated with IV potassium, methimazole and propranolol with quick resolution of weakness. He has been followed in an out-patient basis and he has had no further exacerbations.In this case, we present a case of TPP that was initially diagnosed as cocaine induced periodic paralysis which is an extremely rare disorder with only a couple of described cases in the literature. Diagnosis was initially missed as the patient was clinically euthyroid and had history of recreational drug abuse. Restoration of euthyroidism eliminates attacks of TPP. It is important to recognize and diagnose these patient to prevent further attacks.