I lost weight, but I became weak and cannot walk--a case of nutraceutical (T3)-induced thyrotoxic periodic paralysis.

Thyrotoxic periodic paralysis (TPP) is a rare reversible cause of paralysis and cramping. TPP is usually precipitated by common causes of thyrotoxicosis such as Grave disease or multinodular goiter. TPP precipitated by exogenous triiodothyronine (T3) intake is an extremely rare occurrence with only 3 cases reported to date. We now report a 24-year-old healthy manual laborer who developed quadriparesis during a period of rest after heavy exertion and carbohydrate intake. He had severe hypokalemia (potassium level 1.9 mmole/L). Correction of his hypokalemia reversed the paralysis without rebound hyperkalemia. After a detailed history review, he reported that he had been consuming nutraceuticals containing T3 for 1 month to lose weight, and laboratory studies confirmed factitious T3 toxicosis. There was no evidence of renal or gastrointestinal potassium wasting. This episode of TPP was the first manifestation of thyrotoxicosis in this patient, and avoidance of T3 intake prevented more episodes.