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QWhat treatments are available for Moyamoya disease?
DR. MARIO ZUCCARELLO RESPONDS:
A number of treatment options are available for people with Moyamoya disease (MMD). The best course of treatment will be determined by the patient's age, his or her symptoms, and the size of the stroke caused by MMD.
The disease is caused by blocked arteries at the base of the brain. To compensate for the narrowing arteries and facilitate the flow of oxygen-rich blood, the brain creates collateral blood vessels. When seen on a brain scan, these tiny blood vessels have a hazy, filmy appearance—the “puff of smoke” that gives the disorder its Japanese name. The narrowing of these collateral blood vessels can lead to stroke.
The chance of being diagnosed with MMD in the United States is about one in a hundred thousand. While the cause of MMD is not completely known, a genetic component is suspected of playing a role, particularly in Asian populations. Also, several diseases—including sickle cell anemia, Down syndrome, and neurofibromatosis—have been associated with MMD and may be potential causes.
Once a diagnosis of MMD is confirmed, several treatments may be considered. If few symptoms have appeared, then an anti-platelet drug such as aspirin or clopidogrel (Plavix) might be prescribed to inhibit clot formation.
If there has been a transient ischemic attack (TIA), which is when blood flow to a part of the brain stops for a brief period of time, then revascularization is recommended to prevent future stroke. In direct revascularization, blood vessels outside the brain are connected to blood vessels inside the brain to create immediate blood flow, which increases the amount of oxygen and other nutrients delivered to the brain. During indirect revascularization, an artery or muscle from the forehead is placed on the brain's surface with the hope that, over time, new blood vessels will develop and increase circulation.
While the outlook for someone with MMD depends upon the how rapidly the blockage occurs and by the overall neurologic condition of the patient, revascularization surgery is quite effective in decreasing the progression of strokes. Left untreated, approximately half of MMD patients will continue to experience strokes, seizures, headaches, TIAs, and impaired day-to-day function such as compromised speech or motor function.