Moyamoya Disease

Moyamoya Disease is a progressive, noninflamatory cerebrovascular disease causing stenosis (narrowing) of the terminal portions of the internal carotid arteries and their major branches. In response to this narrowing, the body develops abnormal collateral vessels at the base of the brain that create the characteristic 'puff of smoke' appearance on cerebral angiography. These collateral vessels are fragile and prone to rupture. The disease can present with ischemic symptoms (stroke, TIA) or hemorrhagic symptoms (bleeding), with ischemic presentations more common in children and hemorrhagic presentations more common in adults. Symptoms may be preceded by hyperventilation, emotional stress, or certain activities. Cognitive and behavioral changes can occur, particularly with recurrent ischemic events. The disease is often bilateral, affecting both sides of the brain, though one side may be more severely affected. Progression is variable and unpredictable, making management challenging.