Moyamoya

Moyamoya is a rare disorder. It cause a blockage to the main blood vessels serving the brain as they enter the skull. The name is a Japanese phrase meaning puff of smoke. That is how the lesion looks on an angiogram.

Symptoms of Moyamoya

In children, moyamoya tends to cause mini-strokes (transient ischemic attack) or seizures. Some children may have movements they can't control. Others may show signs of developmental disabilities. Other signs of moyamoya are headaches, speech difficulties or bouts of being unable to move their feet, legs or arms. Because this condition involves bleeding, they may also experience anemia (low levels of iron in their blood).

Adults with moyamoya experience bleeding or strokes. An adult with moyamoya may have spells of fainting or blacking out. He or see may have vision problems that include loss of sight in one eye, blurry vision, poor vision in both eyes or not being able to recognize objects. The condition tends to get worse without treatment. Moyamoya can cause severe brain damage or death.

Causes and Risk Factors for Moyamoya

It's not yet known what causes this condition. The narrowing of the brain's blood vessels may be due to injuries or genetic abnormalities. There may be some links between having moyamoya and having neurofibromatosis or having procedures such as X-rays of the skull, chemotherapy or heart surgery. Moyamoya tends to affect children or adults in their 30s or 40s. It is often found among people of Japanese origin.

Diagnosing Moyamoya

Because moyamoya can cause severe brain damage or even death, it is important to diagnose and treat the condition as quickly as possible.

Your doctor may recommend these tests or imaging scans:

Computed tomography, which can diagnose the presence of a block in the blood vessels going to the brain
Magnetic resonance imaging, which can also diagnose the presence of a block
Angiogram. This is used to confirm the diagnosis of moyamoya. It also shows the doctor the structure of the blood vessels involved.
Single photo emission computerized tomography (SPECT). This is a nuclear medicine study that can show whether the affected areas of the brain have a loss of blood and oxygen supply.

Treating Moyamoya

Without treatment, a person will continue to have strokes. These can cause damage to the person's ability to function. This damage often is not reversible. Several approaches can be used to treat moyamoya:

Drug therapy. Medicines that prevent clots from forming can be helpful. This includes aspirin. Sometimes a calcium channel blocker such as verapamil is prescribed for people with moyamoya. Verapamil helps with the headache that some patients with moyamoya get. The drug needs to be given under the supervision of a neurologist. No drug, however, can prevent the arteries to the brain from narrowing.
Surgery. This is the preferred treatment. It allows the blockage to be bypassed. New blood vessels then develop to bring blood to the brain.

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