Thyrotoxic periodic paralysis-still a diagnostic challenge.

Thyrotoxic periodic paralysis is a life-threatening complication characterized by acute paralysis of proximal muscles with severe hypokalemia in patients with a known or undiagnosed history of thyrotoxicosis. A 24-year-old man was brought to the emergency room with 1 month of progressively worsening lower-extremity weakness followed by urinary retention. He demonstrated severe motor weakness in proximal muscles with absent reflexes.