Moyamoya Disease: What It Is, Symptoms,Causes & Treatment

Written by Medicover Team and Medically Reviewed by Dr Prachi Rahul Pawar , Neurologists

Moyamoya disease is a rare, progressive cerebrovascular disorder characterized by the narrowing and eventual occlusion of arteries in the brain. This condition leads to the formation of abnormal vascular networks, which resemble a "puff of smoke" on angiographic imaging, giving the disease its name-moyamoya, a Japanese term for a hazy, indistinct object.

This disease primarily affects the internal carotid arteries and their main branches, resulting in reduced blood flow to the brain. The body compensates by developing small, fragile blood vessels to supply the affected areas. However, these new vessels are prone to hemorrhage, increasing the risk of strokes.

What Are the Symptoms of Moyamoya Disease?

Symptoms of Moyamoya disease develop as blood flow to the brain decreases. They may begin with mild neurological problems and gradually progress to recurrent strokes or other serious complications if left untreated.

Early Symptoms

The clinical presentation of moyamoya disease can vary significantly, but certain symptoms are more common in the early stages. These symptoms often result from reduced cerebral blood flow and include:

Advanced Symptoms

As the disease progresses, the risk of ischemic and hemorrhagic strokes increases. Advanced symptoms may include:

What Causes Moyamoya Disease?

The exact etiology of moyamoya disease remains unknown. However, genetic factors seem to play a significant role, with certain populations, particularly East Asians, showing a higher prevalence. It is also associated with several conditions, including:

When Should You See a Doctor for Moyamoya Disease?

Consult a neurologist immediately if you experience symptoms suggestive of reduced blood flow to the brain or a possible stroke.

Early diagnosis and timely treatment can reduce the risk of stroke, preserve brain function, and improve long-term outcomes.

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How Is Moyamoya Disease Diagnosed?

Diagnosing moyamoya disease involves a combination of clinical evaluation and radiological imaging. Physicians typically use the following diagnostic tools:

Magnetic Resonance Imaging (MRI)

MRI scans provide detailed images of the brain's structure and blood vessels. They help identify areas of reduced blood flow and detect any previous strokes.

Magnetic Resonance Angiography (MRA)

MRA is a specialized MRI technique that visualizes blood vessels. It is particularly useful for assessing artery narrowing and the presence of abnormal vascular networks.

Computed Tomography Angiography (CTA)

CTA uses X-rays to produce detailed images of blood vessels. It can help confirm the diagnosis and assess the extent of arterial narrowing.

Digital Subtraction Angiography (DSA)

DSA is considered the gold standard for diagnosing moyamoya disease. It involves injecting a contrast dye into the blood vessels and taking X-ray images to visualize the vascular network in detail.

How Is Moyamoya Disease Treated?

The primary goal of treating moyamoya disease is to improve cerebral blood flow and reduce the risk of strokes. Treatment options include both surgical and non-surgical approaches.

Surgical Treatments

Surgery restores blood flow to the brain by creating new pathways around blocked arteries, helping reduce the risk of stroke and improve brain function.

Direct Revascularization

Direct revascularization involves creating a new pathway for blood flow by connecting a scalp artery directly to a brain artery. This procedure, known as a superficial temporal artery to middle cerebral artery (STA-MCA) bypass, provides immediate improvement in blood flow.

Indirect Revascularization

Indirect revascularization techniques encourage the growth of new blood vessels over time. These procedures include:

Non-Surgical Treatments

Non-surgical treatment helps manage symptoms, lower stroke risk, and support brain health through medications, lifestyle changes, and regular monitoring.

Medications

While there are no specific medications for moyamoya disease, certain drugs can help manage symptoms and reduce the risk of strokes. These may include:

Lifestyle Modifications

Adopting a healthy lifestyle can help manage moyamoya disease. Recommendations may include:

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What Is the Prognosis for Moyamoya Disease?

The prognosis of moyamoya disease varies depending on the severity and progression of the condition. Early diagnosis and appropriate treatment can significantly improve outcomes. However, without treatment, the disease can lead to recurrent strokes, cognitive decline, and even death.

Factors Influencing Prognosis

Several factors can influence the prognosis of moyamoya disease, including:

What Are the Risk Factors for Moyamoya Disease?

Although Moyamoya disease can occur in anyone, certain genetic factors, ethnic backgrounds, and associated medical conditions increase the risk of developing this rare disorder.

Genetic Predisposition

Genetic factors are believed to play a crucial role in moyamoya disease. Certain gene mutations, particularly in the RNF213 gene, have been linked to an increased risk of developing the condition.

Ethnicity

The disease is more prevalent among East Asians, particularly in Japan, Korea, and China. However, it can affect individuals of any ethnicity.

Associated Conditions

Several medical conditions are associated with an increased risk of moyamoya disease, including: