Abstracts

Rationale: Moyamoya disease (MMD) is an idiopathic cerebrovascular occlusive disorder and one of the main causes of pediatric stroke in Korea. Electrographically, re-build up phenomenon after hyperventilation is commonly observed. This study describes the clinical features of pediatric MMD, especially focusing on the clinical seizures as presenting symptoms or electrical abnormalities on electroencephalography (EEG). Methods: We retrospectively analyzed the medical records of 194 patients (69 males) diagnosed as moyamoya disease, seen at the department of pediatric neurology and neurosurgery, Asan Medical Center between January 2000 and February 2012. Clinical data included age, sex, presenting symptoms, brain magnetic resonance imaging (MRI) and angiography findings, EEG findings and hospital course after surgical revascularization. Results: Median age at diagnosis was 8.2 (0.4~18) years and median follow-up duration after diagnosis was 6.3 (1~12.2) years. The most common symptoms at presentation was transient ischemic attack (150/194, 77%), and 10 (0.05%) patients presented with seizures. Brain MRI and angiography were performed in all patients, and 73 (37.6%) patients showed cerebral infarction. Among 149 patients who performed EEG, 81 (54.4%) showed posterior and/or centro-temporal slowings and 18 (12.1%) showed epileptiform activities, which abnormalities were more frequently associated with cerebral infarction or hemorrhage (p=0.027). Rebuild-up phenomenon was noticed in 60 (58.8%) among 102 patients who performed effective hyperventilation during EEG recording. Four patients presented clinical seizures or epileptiform activities on EEG after revascularization, caused by hypertension, intracranial hemorrhage or cerebral infarction. These postoperative seizures were also well controlled with antiepileptic medications in all four patients. Conclusions: Seizures and/or epileptiform activities on EEG were often detected in pediatric moyamoya disease. Electrographic abnormalities were significantly associated with the cerebral pathology and related seizures were well controlled with antiepileptic medication in most patients and rarely evolve into epilepsy.