Periodic paralysis: rare presenting symptom of thyrotoxicosis.

Paralysis due to hypokalemia results from an acute shift of potassium into cells or excessive potassium deficit. In the absence of potassium deficit, it is observed in Familial Hypokalemic Periodic Paralysis and in Thyrotoxic Hypokalemic Periodic Paralysis (TPP). This report describes the initial presentation of hyperthyroidism as sudden quadriplegia associated with hypokalemia. A healthy 25-year-old Puerto Rican policeman came to the emergency room with sudden paralysis in the four extremities of five hours evolution. He woke up in the morning and could not get up. The day before admission his legs felt weak, and it was hard to get out of bed. He arrived home at 7:00 PM, ate pasta and vegetables, and went to sleep at 10:00 PM. He had no diarrhea or weight loss, no history of medications or illicit drugs. He has a cousin and an aunt with the diagnosis of hypo-thyroidism. The admission temperature was 36.0 degrees C, pulse 96 per minute, respiratory rate 18 per minute, blood pressure 160/70 mmHg. He was alert and oriented as to time, place and person. He could talk properly and was in no respiratory distress. He had no exophtalmos or lid lag. The thyroid was not enlarged or tender. No pseudoclubbing or pretibial edema was found. There was flaccid paralysis of all extremities, 0/5 legs and 1/5 arms. Deep tendon reflexes could not be elicited. The cranial nerves and sensory examination were normal. The hemogram was within normal limits as were the renal and liver functions. Serum sodium was 140 mEq/L, potassium 1.48 mEq/L, phosphorus 1.4 mEq/L. A random glucose was 155 mg/dl and the arterial Ph was 7.41. The urine potassium was 7.04 mEq/L, sodium 60.8 mg/dl. TSH levelwas < 0.03 ug/d], TUP 50.69% (24-40%), T4 17.6 ug/dl (4.7-11.4 ug/dl) Free T4 Index 28.23. He was managed with intravenous potassium chloride, 80 mEq in a period of seven hours with cardiac monitor. The serum potassium level, after the infusion was completed, was 6.70 mEq/L. No cardiac arrhythmia was documented. Muscle strength recovery was gradual and it was complete 4 hours after the infusion was initiated. The next day the potassium level was within normal limits but a wide pulse pressure and tachycardia still persisted.