What Is Moyamoya Disease?

Having a stroke that paralyzes one side of your body could be a symptom of this rare disease

A stroke that results in one side of your body being paralyzed, seizures and/or muscular weakness could be the first symptom of Moyamoya disease. Sound scary? It can be, but there are effective treatments.

First the good news: Moyamoya disease is rare, according to the National Institute of Neurological Disorders and Stroke. It occurs more commonly in Asian countries or in those of Asian descent; in fact the name was first coined in Japan in the 1960s and literally translates to “puff of smoke.”

The moniker describes the diffused appearance of the jumble of tiny blood vessels associated with the progressive cerebrovascular disorder. These small, fragile vessels cause reduced blood flow, as larger arteries progressively get narrower as a result of the condition.

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Moyamoya disease is more common in children but can also affect adults.

What are the symptoms of Moyamoya disease?

The first symptom of Moyamoya disease in children is usually a stroke that comes on without warning. A child also may experience a series of mini-strokes called recurrent transient ischemic attacks (TIA). Both strokes and mini-strokes often happen with paralysis on one side of the body, seizures or muscular weakness.

“Most of the time, people will present with stroke-like symptoms,” said Jonathan Russin, MD, assistant professor of Clinical Neurological Surgery at USC Neurosciences of the Keck School of Medicine of USC. “You tend to see strokes that are ischemic, where the blood flow doesn’t meet the demand.”

“They usually have initially reversible symptoms, where people will have weakness in one arm that gets better over a couple of minutes,” added Dr. Russin, who also is a surgeon at the Cerebral Revascularization Center of USC, where Moyamoya disease is treated. “They sit down, they relax, and the brain can sort of auto-regulate. And then you can have, if they don’t listen to it … a pretty big stroke in an important area.”

Adults with Moyamoya disease are more likely to experience a hemorrhagic stroke due to bleeding into the brain from the abnormal brain vessels, but they may also have TIA.

“The brain is very dynamic,” explained Dr. Russin. “It’ll start to grow new blood vessels to try and get blood where it needs to go. And the new blood vessels are abnormal.

“The vessels themselves are somewhat sick, and they’re under a lot of pressure, quickly, to try and get blood moving, and you get little micro aneurysms on them, and they can burst. So you can present relatively quickly with bleeding in the brain.”

Other symptoms include vision problems, problems speaking and understanding speech, and sensory and cognitive impairments.

Who is at risk for moyamoya disease?

Asians and those of Asian descent are more likely to have Moyamoya disease than those of other ethnic backgrounds. It may be the result of a gene abnormality; about one in 10 people with the disease have a close relative who also has it. It occurs twice as frequently in women than in men. Symptoms most often appear in children around the age of 5 or adults in their 30s or 40s.

How is Moyamoya disease diagnosed?

Moyamoya disease typically is diagnosed by MRI and, if necessary, a follow-up angiogram.

“Almost always, when you have a stroke, you have to look at the blood vessels,” Dr. Russin said. “And then the blood vessels, the pattern of stenosis and changes in the brain are very characteristic with Moyamoya. So you can pick it up generally on an angiogram or CT scan.”

How is Moyamoya disease treated?

There are many different surgical treatments for Moyamoya disease; are all designed to improve blood flow to your brain. In bypass surgery, scalp arteries are attached to brain arteries, or your doctor may attempt revascularization to widen the damaged blood vessels. Treatment is generally very successful, and most who undergo treatment do not experience any more strokes or other symptoms associated with Moyamoya disease, according to the National Institute of Neurological Disorders and Stroke.

Worried you may have Moyamoya disease? Make an appointment with the Cerebral Revascularization Center of USC about your symptoms.

If you are in the Los Angeles area and are looking for a new primary care physician, be sure to schedule an appointment by calling (800) USC-CARE (800-872-2273) or by visiting http://www.keckmedicine.org/request-an-appointment/.

By: Anne Fritz