Moyamoya Disease
Neurosurgeons from UW Medicine offer expert care for moyamoya disease.
Moyamoya Disease
Neurosurgeons from UW Medicine offer expert care for moyamoya disease.
Key points about moyamoya disease
- Moyamoya disease is a type of “cerebrovascular” disease. This means it affects the blood vessels in your brain.
- The affected blood vessels become narrow or even blocked. This narrowing reduces the amount of blood and oxygen that reaches your brain.
- Moyamoya disease can affect children and adults. It’s also progressive, meaning it gets worse over time.
- Without treatment, moyamoya disease can cause strokes and other serious complications.
- The best treatment for moyamoya disease is surgery. Different types of surgery can improve blood flow in your brain.
What is moyamoya disease?
Your body contains a network of blood vessels called arteries. They carry blood — and oxygen — from your heart to the rest of your body. Some of these arteries travel up to your brain, while others are inside your brain. With moyamoya disease, some of the bigger blood vessels at the base of your brain begin to narrow. Over time, they may even close completely. This narrowing can reduce or block blood flow to your brain, greatly increasing your risk of stroke.
As these blood vessels continue to narrow, your brain will create new ones to replace them. However, the new “backup” blood vessels are often tiny and fragile. They can rupture and cause a brain hemorrhage (also known as a brain bleed or bleeding in your brain).
When viewed on a brain scan, these backup blood vessels often look like wispy curls of smoke. That’s how the disease got its name: the Japanese word “moyamoya” means “puff of smoke.”
There isn’t a cure for moyamoya disease. But treatments can improve your symptoms and decrease your risk of stroke and other complications.
Have you been diagnosed with moyamoya disease?
What are the symptoms of moyamoya disease?
Many people with moyamoya disease don’t have any symptoms until their condition has reached an advanced stage. In some cases, the first sign of the disease is a stroke, transient ischemic attack (TIA) or brain bleeding. This is true in both children and adults.
Sudden symptoms
Strokes, TIAs (ministrokes) and brain bleeds can happen quickly in people with moyamoya disease. And these conditions share some of the same sudden symptoms. These symptoms include:
- Confusion
- Difficulty speaking or understanding speech
- Loss of coordination, including problems walking
- Nausea or vomiting
- Numbness or weakness in the face, arm or leg, especially on one side of the body
- Severe headache
- Vision changes, including vision loss or blurred vision
If you or a loved one has any of these symptoms, call 911 right away. Even though a TIA won’t cause permanent brain damage, a stroke or brain bleed can. Doctors must treat these conditions right away to prevent death or disability.
Gradual symptoms
Some children and adults with moyamoya disease have symptoms that come on gradually and then get worse over time. These symptoms include:
- Chronic headaches
- Cognitive (thinking) problems, such as trouble learning, focusing or remembering
- Developmental delays
- Involuntary muscle movements
- Seizures
- Trouble using the senses (loss of hearing, sight, smell, taste or touch)
It’s important to let your provider know if you have any of these symptoms. The sooner you’re diagnosed with moyamoya disease, the sooner you can begin treatment.
When should I contact my doctor?
Call 911 immediately if:
You develop any of the above stroke or brain bleed symptoms. Do not drive to the hospital. It’s safer and potentially faster for an ambulance to bring you. Paramedics may be able to begin treating you in the ambulance.
Call your doctor if:
You’re concerned about your risk of moyamoya disease based on your family history, symptoms or other factors.
About moyamoya disease
What causes moyamoya disease?
Some people develop moyamoya disease after inheriting an abnormal gene from one of their parents. In other words, this disease can run in families.
For many other people with moyamoya disease, there is no clear reason why it develops.
Who is at risk of moyamoya disease?
Certain risk factors increase your chance of having moyamoya disease. These include:
- Age. The condition can occur at any age. However, it’s most likely to occur between ages 5-10 and 30-50.
- Ethnic background. Moyamoya disease is more common in people of Chinese, Japanese and Korean descent.
- Family history.
- Gender. Moyamoya disease is twice as likely to affect females.
Other medical conditions. People with certain medical conditions have a higher risk of developing moyamoya disease. These conditions include Down syndrome, hyperthyroidism, neurofibromatosis type 1 (NF1) and sickle cell disease.
Diagnosis options for moyamoya disease
How is moyamoya disease diagnosed?
If your provider thinks you have moyamoya disease, they’ll gather information and perform (or order) various tests.
For example, your provider will ask questions about your symptoms and your family history of blood vessel problems in the brain. They’ll perform a neurological exam to check your balance, coordination and reflexes. And they’ll order one or more imaging tests to see whether the blood vessels in your brain are healthy.
Brain imaging procedures
Some of the imaging tests we may use to confirm (or rule out) moyamoya disease include:
- Cerebral angiogram. Your surgeon inserts a catheter (a thin, flexible tube) into a blood vessel in your groin, then gently guides it up to your brain. Next, they inject a contrast agent (liquid dye) through the catheter. Then, with the help of X-ray imaging, they’ll watch how well (and where) the dye flows through your blood vessels.
- CT and CTA. A CT scan uses X-rays to take detailed pictures of your brain. Another type of CT scan, called a CT angiogram or CTA, uses a contrast agent to show how well blood flows through the arteries in your brain.
- MRI and MRA. An MRI scan uses magnetic energy instead of radiation to take pictures of your brain. If your provider needs to see inside the blood vessels, you may have a type of MRI called a magnetic resonance angiogram, or MRA. During an MRA, you may need an IV with liquid contrast agent.
- Single-photon emission computerized tomography (SPECT). A SPECT scan is a type of nuclear imaging test. We give you a small, safe amount of radioactive material we track using special cameras. With SPECT, we can see which areas of your brain aren’t receiving normal amounts of oxygen.
How is moyamoya disease treated?
The treatments you’ll need for moyamoya disease depend on several factors. These include:
- Your age (we use different surgical techniques for children and adults)
- How severely your blood vessels are affected at the time of diagnosis
- The type and severity of your symptoms
Moyamoya disease surgery
For many people with moyamoya disease, surgery is the best treatment. That’s because surgery is the only way to change blood flow patterns in the brain.
The surgeries we use to treat moyamoya disease are called “bypass procedures” or “revascularization procedures.” They help improve blood flow to the brain by:
- Creating new pathways that allow blood to bypass (detour around) a narrowed or blocked artery
- Changing the direction in which blood flows so it reaches the areas of the brain that have not received oxygen
There are several ways your neurosurgeon might accomplish these goals. For example, they can attach an artery on your scalp to one in your brain. Connecting different arteries creates a new way for blood to flow into your brain.
Nonsurgical treatments for moyamoya disease
Your provider may also recommend medication, alone or in combination with surgery.
Medication can’t stop moyamoya disease from progressing. However, certain drugs — including blood thinners and calcium channel blockers — may offer important benefits. These benefits include:
- Preventing blood clots
- Managing complications such as seizures
- Reducing symptoms, including headaches
- Reducing your risk of stroke