Moyamoya disease is a rare, progressive cerebrovascular disorder that is caused by blocked arteries at the base of the brain in an area that is called the basal ganglia. The disease is characterized by the narrowing and/or closing of the carotid artery. Insufficient blood supply causes reduced oxygen to the brain. The reduced oxygen causes the signs and symptoms of Moyamoya disease. Moyamoya means “puff of smoke” in Japanese. “Puff of smoke” describes the way a tangle of tiny vessels look that are formed to compensate for blockage. Moyamoya disease is primarily found in children, but it can occur in adults.
Moyamoya disease was first described in the 1960’s in Japan. It is also found in people in the United States, Europe, Australia and Africa. The cause of Moyamoya disease remains unknown, but there is a possible genetic link. Research shows that there are many cases within certain Japanese families. Moyamoya disease occurs mostly in Asians, but it can occur at different degrees of severity in Whites, Haitians, African Americans and Hispanics. It occurs at the ages of 6 months to 67 years. The highest risk for the disease is during the first ten years of life.
The most common symptom in children is a stroke or repeated transient ischemic attacks (TIAs). Muscle weakness, paralysis that affects one side of the body and seizures will accompany the stroke or TIAs. Other signs and symptoms that occur in both children and adults include headaches, altered consciousness, speech difficulties, vision problems, involuntary movements, mental retardation, psychiatric problems and difficulty with sensory and cognitive functions. Paralysis can also occur in the feet, legs or upper extremities. Most suffer from progressive cognitive deterioration and will eventually die due to intracerebral hemorrhage.
Diagnosis of Moyamoya disease is made by a Cerebral Angiography, Magnetic Resonance Imaging (MRI), and Xenon CT Scans. A Cerebral Angiography is when a dye is injected into the cerebral arteries and then an X-Ray is performed. The dye makes the arteries easier to see. Abnormal vessels will look like a cloud of smoke or as the definition of Moyamoya suggests a puff of smoke. A MRI allows physicians to examine the brain structures to detect strokes that may have occurred. When a Xenon CT Scan is performed, patients breathe Xenon gas. The gas acts as a contrast agent to show regions of low and high blood flow. The Xenon CT Scan reveals blood flow to the areas of the brain in order to determine if enough blood is reaching all areas.
There is no cure for Moyamoya disease, but treatment can help manage the signs and symptoms of the disease. Treatment options include blood thinning medications to reduce the risk of blood clots, corticosteroid medications and surgery to bypass blocked arteries or to open narrowed blood vessels to restore the blood supply to the brain. Children usually respond better to the surgery than adults do.
A hemorrhage is usually the cause of death. Fifty to sixty percent of patients go through a gradual deterioration of cognitive function. This is possibly from recurrent strokes. The mortality rate for Moyamoya disease is 10% in children and 4.3% in adults.
Moyamoya disease is associated with Neurofibromatosis, Tuberous meningitis, Retinitis pigmentosa, Fibromuscular dysplasia, Atherosclerosis, Down’s syndrome and Fanconi’s anemia.
