Moyamoya Disease - Symptoms & Causes

What is moyamoya disease?

Moyamoya disease is a progressive cerebrovascular disorder characterised by the narrowing or blockage of the carotid arteries in the brain. This narrowing leads to the development of a network of tiny blood vessels at the base of the brain to supply blood to the brain tissue.

This condition can result in recurrent strokes and transient ischaemic attacks (TIAs).

The term "Moyamoya" means "puff of smoke" in Japanese, which describes the appearance of these small, tangled vessels on an angiogram.

Moyamoya disease is more prevalent in paediatric patients, but it can also develop in adults.

Types of moyamoya disease:

• Idiopathic moyamoya disease. This type has no known cause and is considered a primary condition.
• Secondary moyamoya syndrome. This type occurs in association with other conditions such as neurofibromatosis, Down syndrome, or previous radiation therapy to the head.

What are the symptoms of moyamoya disease?

The symptoms of Moyamoya disease can vary depending on the age of the patient and the severity of the condition. Common symptoms include:

• Sudden weakness or paralysis, particularly on one side of the body, indicating a stroke or a TIA.
• Recurrent, severe headaches.
• Seizures, particularly seen in children.
• Cognitive decline, including difficulty with thinking, memory, or learning.
• Vision problems, including sudden vision loss or disturbances.
• Speech difficulties: Trouble speaking or understanding speech.
• Involuntary movements such as chorea or dystonia.

When to seek emergency medical attention?

It is crucial to act FAST and seek emergency medical attention if you notice the following stroke symptoms in a loved one:

• Face drooping when you ask them to smile.
• Arm weakness when you ask them to raise one or both arms.
• Speech difficulty when you ask them a question or notice difficulty understanding what you say.
• Time to call emergency services.

What causes moyamoya disease?

The exact cause of moyamoya disease is unknown. However, several factors are believed to contribute to its development:

• Genetic factors. There may be a hereditary component, as the condition tends to run in families, particularly among people of East Asian descent.
• Autoimmune diseases. Conditions such as lupus can be associated with Moyamoya disease.
• Environmental factors. Prior radiation therapy to the head can increase the risk.

What are the complications and related diseases for moyamoya disease?

Due to blood vessels progressively narrowing or being blocked in the brain, several serious complications can occur, including:

• Recurrent TIAs.
• Ischaemic stroke, otherwise known as cerebral infarct.
• Haemorrhagic stroke.
• Cognitive and developmental delays, particularly in children.
• Weakness or paralysis.
• Speech difficulties.
• Seizures.
• Emotional and behavioural changes such as depression, anxiety, and personality changes.

How do you prevent moyamoya disease?

Currently, there is no known way to prevent moyamoya disease due to its unclear cause. However, managing risk factors and monitoring for symptoms can help mitigate complications. This may include:

• Regular medical check-ups for early detection and management of symptoms.
• Genetic counselling for families with a history of moyamoya disease.
• Have a healthy lifestyle through a balanced diet, regular exercise, and avoiding smoking to maintain good vascular health.