Moyamoya disease

A dangerous “puff of smoke”
Moyamoya disease causes major blood vessels at the base of the brain to become progressively narrower and more blocked. To compensate for the blockages in the large blood vessels, tangles of tiny vessels form to help deliver blood to the brain. On imaging scans, these tiny vessels appear light and wispy. This appearance led to the name “moyamoya,” which in Japanese means “puff of smoke.”

People with this condition are at an ever-increasing risk of strokes or mini-strokes (TIAs). They may also have muscle weakness or paralysis on one side of the body, or they may have seizures.

Medicine alone can’t prevent the disease from progressing. Almost two-thirds of patients with Moyamoya disease develop increasing symptoms over five years. Early diagnosis and appropriate treatment are very important. Surgery can restore blood flow to the brain by opening narrowed blood vessels or by creating bypasses around blockages. After surgery, most people experience no more strokes or related problems.

Moyamoya was first described in the 1960s. At that time, it was thought to affect mainly people of Asian heritage. It has now been recorded in people of many ethnic backgrounds, including those of African, American and European heritage. Moyamoya is seen most commonly in children, but it can also occur in adults in their mid-40s. Females have it nearly twice as often as males. The condition tends to run in families.

People affected by Moyamoya disease may experience these symptoms:

  • Ischemic stroke (sustained weakness, numbness in arms and legs, difficulty with speech and vision)
  • TIA (mini-stroke, short attacks of weakness, numbness or difficulty with speech)
  • Hemorrhage (bleeding in the brain due to the rupture of fragile, diseased blood vessels)
  • Headaches
  • Seizures
  • Worsening cognitive or psychiatric changes if the disease is not appropriately treated