Summary

Thyrotoxic periodic paralysis is a potentially life-threatening condition associated with recurrent episodes of muscle weakness and hypokalaemia due to hyperthyroidism. Diagnosis is often delayed or misdiagnosed due to its rarity in the western world and subtle features of hyperthyroidism on initial presentation. Here we present the case of a 25-year-old man who presented to the emergency department (ED) with sudden onset weakness of bilateral upper and lower extremities. His labs revealed hypokalaemia with elevated T4 and suppressed thyroid-stimulating hormone and he was diagnosed with thyrotoxic periodic paralysis. He was treated with potassium repletion, atenolol and methimazole with complete reversal of his paralysis within the next day. Unfortunately, he failed to keep the follow-up appointment after discharge, ran out of his methimazole and landed up in the ED again.