Alternating hemiplegia of childhood.

We report 22 cases of alternating hemiplegia of childhood. In addition to repeated episodes of hemiplegia lasting from a few minutes to several days, the disease was characterized by an onset before 18 months of age, the occurrence of tonic or dystonic attacks, nystagmus, dyspnea and other autonomic phenomena, and the development of cognitive impairment and of a choreoathetotic movement disorder. All the patients also had episodes of quadriplegia that occurred either when a hemiplegia was shifting from one side to the other or as an isolated manifestation. Such episodes were often severe and followed by developmental deterioration. In all children, sleep consistently relieved both weakness and associated paroxysmal phenomena, but these would reappear 10 to 20 minutes after the children awakened, during long-lasting episodes. Although six patients also had epileptic seizures, the condition seems to be distinct from epilepsy, and the clinical features and poor outcome differentiate it from migraine. Treatment with the calcium-entry blocker flunarizine was partially effective.