What is Moyamoya disease?

Moyamoya disease is a progressive disorder in which the large arteries inside the skull (vessels that carry blood to the brain) narrow and often completely close off. Small branches of these arteries enlarge to bypass the blockage, probably as a response to this narrowing. The cause of the narrowing is unknown.

These small branches that grow larger (and maybe more numerous) give the disorder its name. "Moyamoya" is a Japanese term, meaning “puff of smoke,” that is used to describe the hazy appearance of these small vessels on an angiogram.

This disorder is common in Asia, where it most frequently affects children. In North America, it is much less common and generally affects women in their 3rd, 4th and 5th decades of life, frequently causing stroke.

Untreated, moyamoya disease can cause headaches, speech problems, and progressive cognitive and learning impairment. It can result in strokes, during which blood flow to the brain stops, resulting in weakness or numbness of limbs, speech difficulties, visual or walking problems. People with moyamoya disease also may have transient ischemic attacks (TIA), often referred to as “mini-strokes,” with temporary stroke-like symptoms.

Drugs have proven ineffective in the treatment of moyamoya disease. In adults, a surgical revascularization procedure that directly bypasses blocked arteries is most commonly recommended, when feasible. This procedure offers an immediate improvement in blood supply to the brain. Indirect revascularization – in which an artery or muscle is laid directly on the surface of the brain – can also improve blood flow to the brain over a longer period (6-8 weeks). Indirect procedures are more frequently used in children.

Without treatment, some people with moyamoya will experience mental decline and multiple strokes, and may die from the disease. Surgery may help these patients to live active and full lives with reduced risk of stroke. Other patients may do well with no treatment. The center's research is aimed at helping to figure out how to identify patients at risk for future stroke and those likely to do well with no treatment.

1. NINDS Moyamoya Disease Information Page. National Institute of Neurological Disorders and Stroke website. Accessed 2/16/2012.

Recent Publications of the Moyamoya Center at Washington University:
Ashley WW Jr, Zipfel GJ, Moran CJ, Zheng J, Derdeyn CP. Moyamoya phenomenon secondary to intracranial atherosclerotic disease: diagnosis by 3T magnetic resonance imaging. J Neuroimaging. 2009 Oct;19(4):381-4.

Hallemeier CL, Rich KM, Grubb TL, Jr., Chicoine MR, Moran CJ, Cross DT III, Zipfel GJ, Dacey RG Jr, Derdeyn CP. Outcome in North American adults with Moyamoya phenomenon. Stroke 2006; 37:1490-1496.

For a referral to a Washington University neurologist or neurosurgeon at Barnes-Jewish Hospital, call [Dynamic_Phone_Number].

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