Periodic thyrotoxic paralysis (TPP) is a disease that usually affects Asian men from 20 to 50 years. It is secondary to genetic mutations of ion channels for the transport of sodium and potassium. It is characterized by recurrent and brutal bouts of paresis / flaccid paralysis, without sensory involvement, in a context of hyperthyroidism. Seizures preferentially affect proximal muscles and are often associated with severe hypokalemia. However, serious repercussions are rare, except in cases of extreme weakness of the respiratory muscles or cardiac arrhythmia induced by hypokalemia. The treatment of ionic disorders, followed by the correction of hyperthyroïdism, leads to the complete disappearance of symptoms.