Thyrotoxic periodic paralysis terminated with intravenous propranolol.

Thyrotoxic periodic paralysis (TPP) is an uncommon syndrome that can be fatal. We report the case of a patient with acute, severe muscle weakness and hypokalemia who was diagnosed in the emergency department to have thyrotoxicosis with acute TPP. The hypokalemia was treated aggressively with potassium without effect. After administration of i.v. propranolol, the patient had complete resolution of symptoms, with mild rebound hyperkalemia. The literature on the use of propranolol in TPP is reviewed, and the known pathophysiology of TPP is discussed.