[Thyrotoxic hypocalemic periodic paralysis: report of 3 cases]

Thyrotoxic hypokalemic periodic paralysis (THPP) is a rare hyperthyroidism complication much more frequent in Asians and Caucasians. We present 3 cases of THPP occurring in Brazilian male patients with 28 years old (y) (Case 1), 29 y (Case 2) and 60 y (Case 3), respectively. They were admitted following an episode of flacid paralysis of extremities. Whereas case 1 reported recurring episodes of paralysis crises, cases 2 and 3 reported only one episode. Signs and symptoms of thyrotoxicosis, such as weigh loss, diaphoresis, extremities tremor, palpitation and mild diffuse goiter were present in the first case; while the second case only presented ophthalmopathy and the third patient referred that 2 years before his admission he presented an episode of cardiac arrhythmia but did not have thyroid function evaluation at that time. Their laboratory findings were hypokalemia, low TSH and raised free T4. They were treated with intravenous potassium, oral propranolol and tiamazol with remission of the symptoms. We report these cases to emphasize the importance of recognizing hyperthyroid periodic paralyses to avoid missing a treatable and curable condition.