Moyamoya Disease

Moyamoya gets its name from the Japanese word for “puff of smoke.” When viewed on a cerebral angiogram, the new blood vessels look like black wispy clouds or a puff of smoke drifting into the air.

In most cases, there is no known cause for moyamoya, but it can be found in association with other conditions such as:

• Brain tumors at the base of the brain that form after radiation therapy
• Down syndrome
• Connective tissue disorders (Ehlers-Danlos syndrome, Marfan syndrome)
• Graves' disease
• Neurofibromatosis
• Sickle cell disease

Some children may develop moyamoya after radiation therapy or after a viral illness. About 1 in 10 children with moyamoya also have a relative with the condition. In those cases, the condition may be inherited.

Moyamoya can occur in both children and adults.

The symptoms of moyamoya are caused by reduced blood flow to the brain and weakened blood vessels. The first sign of moyamoya is often a transient ischemic attack or a stroke. Symptoms of moyamoya include:

• Stroke or stroke-like symptoms
• Transient ischemic attacks (ministrokes)
• Weakness or numbness on one side of the body
• Tingling on one side of the body
• Seizures
• Migraine-like headaches

Moyamoya can affect one (unilateral) or both sides (bilateral) of the brain. Without treatment, children with moyamoya can experience multiple strokes that can lead to progressive intellectual and cognitive disability.

If your child shows signs of moyamoya, neurologists and neurosurgeons will perform specific tests to make an accurate diagnosis. Surgery is the only cure for moyamoya. Most children make a complete recovery and can return to normal activities within a month.

Diagnosis of Moyamoya

The following exams and tests are performed to diagnose moyamoya:

• Medical history. A neurologist or neurosurgeon will review your child’s medical history.
• Neurological exam. The doctor will perform a detailed neurological exam, looking for signs of moyamoya, including weakness and/or numbness or tingling in the limbs.
• Cerebral angiogram. A neurointerventionalist uses this test to study the arteries in the brain. A cerebral angiogram is performed while your child is asleep under anesthesia. Moyamoya precautions are used during anesthesia to ensure your child’s safety and to avoid the risk of stroke. A catheter is inserted into the femoral artery in the leg. The catheter is passed from the femoral artery to the internal carotid artery in the neck. Dye is then injected into the catheter and flows through selected arteries of the brain and the external carotid circulation. A cerebral angiogram highlights blockages and the formation of any new blood vessels. It creates a map of the brain’s blood vessels. This map is used to determine the need for surgery and the availability of external carotid vessels that can be used as donor vessels for surgery.

If diagnostic tests determine that moyamoya disease is present, a neurosurgeon will discuss the condition with you and your child and will work with you to create a surgery plan for definitive treatment.