Periodic family paralysis is a relatively rare disease of human beings. In an extensive review of the literature on the subject, Talbott1 stated that approximately 400 typical cases have been reported since Musgrave2 first described a case in 1727.
The disease is characterized by the periodic development of acute flaccid paralysis, which usually begins in the extremities and progresses toward the trunk. The patient loses the power to move his limbs, but he can usually breathe, eat and speak freely, and the functions of his internal organs appear not to be disturbed. The deep reflexes of the affected extremities are absent at the height of the attack. After a period of time, usually a few hours, but in some instances two or three days, the patient recovers from the attack spontaneously. Another attack may occur within twelve to twenty-four hours or after a longer interval. During the attacks,