A 20-year-old Chinese man with recurrent hypokalemic periodic paralysis and delayed diagnosis.

Periodic paralysis in the setting of hypokalemia can be the result of several underlying conditions, requiring systematic evaluation. Thyrotoxic periodic paralysis (TPP), a curable cause of hypokalemic periodic paralysis, can often be the first manifestation of thyrotoxicosis. Because the signs and symptoms of thyrotoxicosis can be subtle and clouded by the clinical distress of the patient, the diagnosis of the underlying metabolic disorder can be overlooked. The authors report a case of TPP in a young Chinese man in whom the diagnosis of thyrotoxicosis was initially missed. This case illustrates the lack of awareness of TPP among many physicians, delay in the diagnosis of TPP and the importance of performing thyroid function testing in all cases of periodic paralysis.