Moyamoya Disease | Frequently Asked Questions

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Contact the Moyamoya Disease Program

At what age do moyamoya symptoms typically emerge?

Although 7 years is the average age of diagnosis, moyamoya disease can affect people of any age.

Are there different types of moyamoya disease?

Yes. The childhood form of the disease causes stroke symptoms, such as slurred speech, headaches and seizures. Young adults and older people with moyamoya may also have the hemorrhagic form of the disease, in which a brain hemorrhage — bleeding in the brain — is a symptom. Here at Boston Children’s Hospital, we’ve compiled data suggesting that it’s very rare for someone with childhood moyamoya disease to develop the hemorrhagic form later in life.

Will my child be OK?

The long-term outlook for a child with moyamoya disease depends very much on their individual circumstances, including:

  • their symptoms at the time they are diagnosed
  • whether one or both sides of the brain are affected
  • whether they have already suffered a transient ischemic attack (TIA) or stroke
  • their overall health
  • how soon they receive surgical treatment after diagnosis

Your child’s treatment team can give you detailed information on their particular situation, and can recommend the best course of action.

Is it possible that my child’s moyamoya disease will go away on its own?

No. It’s important for families to understand that moyamoya disease is a progressive condition: The dangerous narrowing in the brain’s blood vessels continues to worsen. Some children’s symptoms become gradually more severe over months, or even years, but others suffer TIAs or strokes in a relatively short period of time. Surgery to provide a new, healthy source of blood flow to the brain is a must to reduce the likelihood of a potentially life-threatening stroke. The good news is that the children and adults we have treated surgically have had an excellent rate of recovery.

Should my child’s physical activity be restricted?

Symptoms of moyamoya disease are often brought on, or made worse, by activities that can lead to hyperventilation (over-breathing), a drop in blood pressure or dehydration — all risk factors for a stroke. To lessen the risk of stroke, activities should be restricted — especially strenuous play or sports than can cause overexertion. Your clinician can make more detailed recommendations for your child.

Can adults develop moyamoya disease? How is the condition different than in kids?

Though the average age of a person with moyamoya disease when they are first diagnosed is 7, the disease can also develop in older children, adolescents and adults. Adults may have the hemorrhagic form of moyamoya. Based on the evidence we have collected here at Boston Children’s, it appears very unlikely that a child with moyamoya disease will develop the hemorrhagic form later in life. Our Moyamoya Disease Program treats adults as well as children. Contact us to request an appointment, second opinion or consultation.

Why is surgery the recommended treatment for moyamoya disease?

Moyamoya disease is a progressive condition: The degree of narrowing in the brain’s blood vessels only grows more pronounced over time, as will the associated symptoms and the risk of a potentially fatal stroke. To combat this dangerous process, a new source of nourishing blood vessels must be found. Surgery is necessary to introduce new vessels and restore healthy blood flow to the brain.

Why does Boston Children’s recommend the pial synangiosis procedure in particular?

Since the pial synangiosis procedure was first developed at Boston Children’s more than 25 years ago, we have used the operation to successfully treat more than 400 children and adults with moyamoya disease. Pial synangiosis is particularly effective because it:

  • uses a wide opening of all of the membranes covering the brain
  • directly attaches the donor artery to the brain surface, promoting more rapid
  • development of arterial ingrowth to nourish the child’s brain
  • takes advantage of the tendency of the brains of children with moyamoya disease
  • to attract new blood vessels from any source that is made available by the surgeon

Most children who have pial synangiosis are released from the hospital within a few days, and usually need only regular exams and monitoring as follow-up.

How likely is it that my child will suffer a stroke during surgery?

Based on more than 400 patients with moyamoya disease who have undergone pial synangiosis surgery at Boston Children’s, it’s estimated that four to seven percent will suffer a new stroke either at the time of surgery or within the first month after the operation. These strokes can range from mild TIAs to more severe episodes.

It’s important to note that most of the Boston Children’s patients who suffered strokes during or after the procedure were already experiencing serious neurological symptoms — including frequent TIAs or strokes — in the weeks or months leading up to their surgery. We believe that patients with this type of history are at greater risk, and as a result, we will typically wait four to six weeks after any stroke episode before proceeding with surgery. Nearly all of the Boston Children’s patients who suffered a stroke at the time of, or just after, surgery have gone on to make excellent recoveries.

Is the rest of my family at risk for moyamoya disease? Should my child’s siblings be screened?

Inherited moyamoya disease appears to be quite rare in the Western hemisphere. If your family doesn’t have a history of strokes, we don’t usually recommend screening siblings of children with moyamoya disease for the condition. However, if one of your children is experiencing either warning signs of a stroke — like severe headaches or seizures — or an actual TIA or stroke, you should seek immediate medical treatment, including screening for moyamoya.

We do recommend screening in these cases:

  • identical twins of children with moyamoya disease
  • siblings of children with moyamoya disease, in families with a history of early stroke,/li>

Does Boston Children’s recommend or offer genetic testing for moyamoya disease?

There is no current method of determining before birth whether a baby is likely to have moyamoya disease.

Can my child go on to live a normal adult life, including having a family?

While the rarity of moyamoya disease — and the relative newness of surgical advances like pial synangiosis — means data on long-term outcomes is somewhat limited, the results we have seen here at Boston Children’s are very encouraging.

In our Moyamoya Disease Program, we continue to track the progress of all of our patients, dating back to the first pial synangiosis procedure in 1985. The vast majority of the 400-plus patients treated for moyamoya disease at Boston Children’s have done exceedingly well: More than two-thirds are leading normal, active adult lives today, with no noticeable neurological problems. In addition, several of the children we treated in the 1980s and 1990s now have families of their own. This includes many women who have experienced uncomplicated pregnancies and deliveries.

Boston Children’s is so much more than a hospital—it’s a community of researchers, clinicians, administrators, support staff, innovators, teachers, patients and families, all working together to make the impossible possible. ”
- Sandra L. Fenwick, President and CEO

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