Detailed Information on Moyamoya Disease

Moyamoya illness is a rare, advanced cerebrovascular disorder characterized by the narrowing or occlusion of main blood vessels leading into the brain, and the formation of abnormal blood vessels called moyamoya vessels. It can occur at any time, but is most commonly diagnosed in childhood between ages 5 - 15 and during adulthood between ages 30 - 40. Mortality rates are approximately 10% in adults and 4.3% in children.

Signs and symptoms of moyamoya disease involve speech deficits, cognitive impairment, involuntary movements, vision problems, seizures and stroke. In children, moyamoya illness usually presents with symptoms and signs of a transient ischemic attack (TIA) or completed stroke. Children also frequently experience temporary weakness in one or more of their extremities during strenuous physical activity or when crying. Adults can also present with brain hemorrhage causing neurologic symptoms in addition to nonhemorrhagic strokes, TIA’s and headaches.

Most patients with moyamoya disease will suffer progressive cognitive deterioration and eventually die due to intracerebral hemorrhage. In persons with moyamoya disease, the death rate (usually from brain hemorrhage) is somewhere between 5-10%. The precise cause of moyamoya disease is unknown. There are several disease states that are associated with moyamoya disease. These include: neurocutaneous syndromes such as Sturge-Weber syndrome and neurofibromatosis, meningitis, Down syndrome, fibromuscular dysplasia, childhood brain radiation, Fanconi's anemia, and brain atherosclerosis.

Approximately 10% of cases of Moyamoya syndrome are due to a genetic cause and are termed primary Moyamoya syndrome. Vasculitis, or inflammation of the blood vessel wall, which can occur in a range of medical conditions, may also lead to the development of moyamoya disease. There is no cure for moyamoya disease. Treatment is aimed at relieving symptoms and includes aspirin, vasodilators, or anticoagulants. Blood-thinning medications to decrease the risk of blood clots. Surgery to bypass blocked arteries or open narrowed blood vessels in order to restore blood supply to the brain (revascularization). Rehabilitation with physical therapy, occupational therapy, and speech therapy should be considered.