A 6-year-old girl presenting with a 6-month history of classical familial migraine, complicated by transitory hemiparesis and moyamoya disease diagnosed by MRI, is reported from the Kaiser Permanente Medical Center, Hayward, CA. Headaches occurred each week and were associated with nausea, vomiting, and photophobia. She awoke on 3 occasions with right-sided weakness, numbness, and garbled speech. All symptoms resolved after two hours of sleep. Neurologic exam was normal between attacks. MRI showed bilateral occlusion of the carotid arteries and increased vascularity of collateral vessels in the basal ganglia, consistent with moyamoya. 
COMMENT. Children with a diagnosis of hemiplegic migraine may have a vascular malformation or moyamoya disease as the underlying pathology. The clinical course depends on the rapidity and extent of vascular occlusion and the ability to develop a collateral circulation. Early diagnosis and surgical revascularization have been advocated because of the risk of permanent neurologic deficits. (See Ped Neur Briefs July 1987, and Progress in Pediatric Neurology, Chicago, PNB Publ, 1991, pp389-391).