17244 Moyamoya Disease

Overview

Moyamoya disease is a rare, progressive blood vessel disorder that affects the brain. The main arteries at the base of the brain become narrowed or blocked. To compensate, the body grows tiny, fragile vessels that try to deliver blood around the blockage. On imaging scans, this tangle of tiny vessels looks like a puff of smoke — the Japanese word 'moyamoya' means 'puff of smoke'. This condition can lead to strokes and other neurological problems.

No, Moyamoya disease is rare. It occurs in about 1 in 1,000,000 people in Europe and North America, though it is more common in parts of East Asia.

Moyamoya can affect anyone, but it is more common in people of East Asian descent and slightly more common in females. It has two main age peaks: in children and in adults in their 40s and 50s.

Symptoms

Common symptoms

• Sudden weakness or numbness on one side of the body
• Difficulty speaking or understanding speech
• Vision changes, such as blurred or double vision
• Severe headaches
• Temporary loss of blood flow to the brain (called a transient ischaemic attack or TIA)
• Seizures

Symptoms in children

• Strokes or transient ischaemic attacks (TIAs) are the most common signs
• Sudden weakness on one side of the face or body
• Speech difficulties (trouble forming or understanding words)
• Unexplained crying or irritability
• Developmental delays or regression in skills
• Involuntary jerking of an arm or leg

Symptoms in older adults

• Bleeding in the brain (haemorrhagic stroke) is more common in adults than in children
• Sudden severe headache
• Nausea and vomiting
• Drowsiness or confusion
• Weakness or numbness on one side of the body
• Seizures

Causes

Main causes

• The exact cause of Moyamoya disease is unknown, but it is not caused by anything you did or did not do.
• Moyamoya can be inherited (familial) in some families, meaning it runs in families.
• It may also be associated with certain health conditions such as Down syndrome, sickle cell disease, or neurofibromatosis type 1.

Risk factors

• Family history of Moyamoya disease
• Being of East Asian descent (especially Japanese, Korean, or Chinese)
• Having certain genetic disorders or blood disorders
• Being female (it occurs slightly more often in girls and women)

When to see a doctor

See a doctor urgently if:

• If you or your child has any sudden neurological symptoms such as weakness, speech problems, or vision loss — even if they go away — seek medical care immediately.
• If you have a sudden, severe headache, call your local emergency number right away.

Book a routine appointment if:

• Talk to your doctor about recurring headaches, especially if they are unusual for you.
• If you have concerns about your child's development or movements, bring them up with your healthcare provider.

Diagnosis

A doctor will start by asking about your symptoms, medical history, and family history. They will also do a neurological examination to check strength, coordination, reflexes, and alertness. If they suspect a problem with blood vessels in the brain, they will order imaging tests.

Tests that may be done

• Magnetic resonance imaging (MRI) — uses a strong magnet and radio waves to create detailed pictures of the brain.
• Magnetic resonance angiography (MRA) — an MRI technique that specifically looks at blood vessels in the brain.
• Computed tomography (CT) angiography — a CT scan with contrast dye that shows blood vessel blockages or narrowing.
• Cerebral angiography — a more detailed test where a thin tube is inserted through a blood vessel in the groin or arm, and dye is injected into the brain's arteries. This is the most precise test for Moyamoya.

What to expect at your appointment

Imaging tests are usually done in a hospital or clinic. Some require you to lie still in a scanner; some use a contrast dye injected into a vein (or, for cerebral angiography, into an artery). It can take from 30 minutes to a few hours. Your healthcare team will explain each test beforehand and watch over you during the procedure.

Treatment

Treatment for Moyamoya disease has two main goals: prevent strokes and improve the supply of blood to the brain. The right treatment depends on your age, symptoms, and how far the disease has progressed. A specialist team — including neurologists, neurosurgeons, and stroke experts — will create a plan tailored to you.

Self-care at home

• Take any prescribed medications exactly as directed.
• Keep your blood pressure within target range with lifestyle changes and medications prescribed by your doctor.
• Attend scheduled follow-up appointments so the disease can be monitored.
• Learn the signs of stroke and make an emergency plan with your family.

Medical treatments

Medical treatment may include medicines that help prevent blood clots from forming (antiplatelet or blood-thinning medications). Your doctor may also treat conditions that increase stroke risk, such as high blood pressure or high cholesterol. Medicines can help reduce the chance of small 'warning' strokes (TIAs) but do not reverse the narrowing of the arteries.

When is surgery considered?

In many cases, especially when symptoms have already occurred, doctors may recommend a type of brain surgery called revascularisation. During this operation, the surgeon uses a blood vessel from the scalp to create a new pathway for blood to reach the brain. Surgery has been shown to lower the long-term risk of stroke in many people with Moyamoya disease. Your specialist team will talk through the benefits and risks with you.

Living with this condition

Living with Moyamoya disease means managing stroke risk and staying in tune with your body. Many people lead full lives with the condition, especially when it is discovered early and treated properly. It's important to attend regular check-ups, take your medicines, and seek urgent care if new symptoms appear.

Lifestyle tips

• Do not smoke and avoid exposure to second-hand smoke.
• Avoid recreational drug use, including stimulants like cocaine or amphetamines.
• Stay hydrated and avoid becoming overheated during exercise or in hot weather – dehydration can increase stroke risk.
• Get enough sleep and manage stress through relaxation techniques, counselling, or gentle hobbies.

Diet and exercise

Eat a balanced diet rich in vegetables, fruits, whole grains, and healthy proteins. Limiting salty foods can help manage blood pressure. Regular light-to-moderate exercise — such as walking, swimming, or cycling — is generally beneficial, but talk to your doctor before starting a new exercise routine, especially if you are planning intense activity.

Mental health and emotional wellbeing

Living with a chronic brain condition can be stressful, and it is natural to feel anxious or depressed at times. It is important to talk to your healthcare team about how you are coping. A psychologist or counsellor can help. If you are in an emotional crisis, please reach out to a crisis support line — a caring person will listen.

Prevention

There is no known way to prevent Moyamoya disease itself, because its cause is not fully understood. However, you can take steps to reduce your risk of stroke and keep your brain as healthy as possible.

Vaccines

There is no vaccine to prevent Moyamoya disease. Staying up to date with recommended vaccinations (such as flu and COVID-19) is a good idea for everyone, especially people with chronic conditions — talk to your doctor about what is right for you.

Screening programmes

If you have an immediate family member (parent, sibling, or child) with Moyamoya, screening might be possible in some healthcare systems. This usually involves a non-invasive scan like MRI/MRA. Talk to your doctor about whether screening is appropriate for your family situation.

Complications

If left untreated

• Without treatment, Moyamoya disease can lead to repeated strokes, which may cause permanent brain damage, weakness, speech problems, or vision loss.
• It can also cause bleeding in the brain (haemorrhagic stroke), which can be life-threatening.

Long-term outlook

The outlook for Moyamoya disease has improved greatly with modern treatment. Surgical revascularisation has been shown to reduce the risk of future strokes by around 60–80%. Many children and adults who receive treatment go on to live active, independent lives. The outcome depends on how early the disease is found, how severe it is, and how well you and your medical team manage your stroke risk.

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