Acute generalized weakness due to thyrotoxic periodic paralysis.

T periodic paralysis (TPP) is a disorder characterized by thyrotoxicosis, hypokalemia and predominantly proximal lower limb paralysis. Despite the female predominance of hyperthyroidism, TPP occurs most frequently in males in a ratio of 20:1, and 90% of patients are of Asian descent. Prodromal symptoms may consist of muscle stiffness or cramping. Sensation, as well as bulbar and respiratory muscle strength, remains intact. Reflexes may be decreased or absent. Attacks may be precipitated by a high carbohydrate meal (secondary to insulin secretion) or physical exertion. In one series, 84% of attacks occurred between 1 and 6 am. Episodes are acute in onset and last 1–96 hours. As in this patient, symptoms and signs of hyperthyroidism may be subtle at initial presentation. Electrocardiographic findings such as ST-segment depression with T-wave flattening and the presence of U waves are TEACHING CASE REPORT PR AC T I C E