Moyamoya disease is an extremely rare disorder in most parts of the world. In Japan the overall incidence is higher (0.35 per 100,000).[1] In North America, women in the third or fourth decade of life are most affected. These women frequently experience transient ischemic attacks (TIA), cerebral hemorrhage or no symptoms. They have a higher risk of recurrent stroke and may be experiencing a distinct underlying pathophysiology compared to patients from Japan. Data suggest a potential benefit with surgery if early diagnosis is made.[2] The pathogenesis of Moyamoya disease is unknown. Moyamoya disease is characterized by progressive intracranial vascular stenoses of the circle of Willis, resulting in successive ischemic events. Hemorrhagic events can also occur. The condition leads to irreversible blockage of the carotid arteries to the brain as they enter into the skull. It is a disease that tends to affect children and adults in the third to fourth decades of life. In children it tends to cause strokes or seizures. In adults it tends to cause bleeding or strokes. The clinical features are cerebral ischaemia (strokes), recurrent TIAs, sensorimotor paralysis (numbness in the extremities), convulsions and/or migraine-like headaches.
The process of blockage (vascular occlusion) once it begins tends to continue despite any known medical management unless treated with surgery. The repeated strokes can lead to severe functional impairment or even death so it is important to recognize these lesions and treat them early on. Without treatment, there is progressive deterioration of neurologic function and re-hemorrhage.
Moyamoya can be either congenital or acquired. Patients with Down syndrome, neurofibromatosis, or sickle cell disease can develop Moyamoya malformations. It is more common in women than in men.[3] Brain radiation therapy in children with neurofibromatosis increases the risk of its development.
Last update: 2008-05-06 13:32:15 Moyamoya | Copyright 2008 HubHip.com