Moyamoya disease is a rare, progressive cerebrovascular disorder caused by blocked arteries at the base of the brain in an area called the basal ganglia. The name moyamoya means puff of smoke in Japanese and describes the look of the tangle of tiny vessels formed to compensate for the blockage. Moyamoya disease was first described in Japan in the 1960’s and it has since been found in individuals in the United States , Europe, Australia , and Africa. The disease primarily affects children, but it can also occur in adults. In children, the first symptom of Moyamoya disease is often stroke.
Moyamoya disease is a progressive disorder that affects the blood supply to the brain. It is rare, but is being detected more frequently with recent advances in diagnostic imaging. It can occur at any time, but is most commonly diagnosed in childhood between ages 5 - 15 and during adulthood between ages 30 - 40.
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.
The most common symptoms of moyamoya disease in children is stroke or repeated transient ischemic attacks (TIAs). These symptoms are often accompanied by muscular weakness or paralysis affecting one side of the body (hemiparesis) and seizures. The most common symptom in adults is stroke. Other symptoms in both children and adults include altered consciousness, speech difficulties (aphasia), vision problems, involuntary movements, and difficulty with sensory and cognitive functions. Most patients with moyamoya disease will suffer progressive cognitive deterioration and eventually die due to intracerebral hemorrhage.
Moyamoya disease (MMD) is a progressive occlusive disease of the cerebral vasculature with particular involvement of the circle of Willis and the arteries that feed it. Moyamoya (ie, Japanese for "puff of smoke") characterizes the appearance on angiography of abnormal vascular collateral networks that develop adjacent to the stenotic vessels. The steno-occlusive areas are usually bilateral, but unilateral involvement does not exclude the diagnosis.
There's no cure for moyamoya disease. But treatment may help manage the signs and symptoms of the disease. Moyamoya disease is a rare, progressive cerebrovascular disorder caused by blockages in the blood vessels at the base of the brain, which impair blood flow to the brain. In an effort to circumvent these blockages, the body forms abnormal blood vessels to reroute blood flow to your brain. The exact cause of these blockages isn't known.
The disease can cause episodes of weakness, paralysis in a limb or on one side of the body, sensory impairment, involuntary movements, headaches, speech problems, dizziness, or seizures. The disease also carries the risk of mental retardation and sustained neurological problems. Severe immediate problems include the risk of transient ischemic attack (TIA or "mini-stroke"), in which the blood flow to the brain is temporarily completely blocked; stroke, in which the blockage is sustained; or intracranial hemorrhage, bleeding in the brain. Hemorrhage and stroke are neurological emergencies that require immediate treatment.
Procedures to enhance cerebral flow produce variable results. Indirect revascularisation techniques, which rely on the development of collateral vessels to circumvent the block, seem to produce the best results in paediatric patients. The commonest technique, known as encephalomyoduroarteriosynangiosis (EMDAS) involves repositioning the richly vascularised temporalis muscle and the temporal artery along the lateral brain surface, and suturing them to the dura.
by Peter Hutch
