Moyamoya Disease

This is a rare disorder that impacts the blood vessels in the brain. It may cause bleeding in the brain and a stroke in the affected part of the brain. It is called moyamoya disease, and it cannot be cured. That’s why the treatment goal is to relieve the symptoms, prevent blood clots, and restore blood flow to the brain. In most cases, doctors recommend medicines and surgery.

Furthermore, moyamoya disease is a type of cerebrovascular disease (a health condition that negatively affects the blood vessels in the brain). In people with this condition, at least one of the carotid arteries is narrowed or closed. These arteries deliver oxygen-rich blood to about two-thirds of the brain. Over time, the brain begins to produce new blood vessels to make up for the blood and oxygen from the blockage. However, these arteries are emergency backup vessels that are smaller and usually weaker than the blocked arteries. Stroke and bleeding in the brain often occur because these small arteries cannot supply the brain with enough oxygen-rich blood.

Generally, this condition occurs rarely (most commonly in Japan), and it affects about 5 in every 100,000 people. In the United States, fewer than 5,000 people are diagnosed with moyamoya disease.

Symptoms

Typically, the symptoms are different among people with moyamoya disease because they depend on which part of the brain is affected. Mostly, the first signs of this disease are stroke or frequent transient ischemic attacks (TIAs). Check for other symptoms of moyamoya disease below:

Aneurysm (ballooning or bulging of a blood vessel that can burst)
Developmental delays
Headaches
Brain hemorrhage (bleeding in the brain)
Involuntary movements
Seizures
Problems with the cognitive abilities (including remembering, learning, and paying attention) and senses (such as sight, hearing, smell, touch, and taste)

If you or your child has any of the symptoms listed above, immediately contact your healthcare professional. Otherwise, it may lead to permanent damage to the brain.

Causes and Risk Factors

Healthcare providers do not know the exact cause of moyamoya disease, but it can be acquired or inherited. Nowadays, researchers continue to study genes that could pass form biological parents to their biological children and cause moyamoya disease. However, there are other factors that may also contribute to this disorder. For example, inflammation, infection, exposure to toxins, and others. Sometimes, this condition is called moyamoya syndrome or phenomenon. Check some examples of these other disorders below:

Physicians have also identified some factors that could elevate your risk of developing moyamoya disease. For example:

Ethnicity – Physicians have noticed that genetic forms of moyamoya syndrome are more common among people of Japanese ancestry.
Gender – Females are twice as likely to develop moyamoya disease compared to males.
Age – While it may occur at any age, it commonly occurs between the ages of 5 and 10 or 30 and 50.
Family history – If you have a parent or sibling with moyamoya disease, your risk of developing it significantly increases. Most of the time, a mutation in the RNF213 gene is associated with moyamoya disease.
Autoimmune disorders – People with rheumatoid arthritis or systemic lupus erythematosus are more prone to moyamoya disease.
Meningitis
Brain tumors
Chronic (long-term) inflammation
Smoking
Unmanaged hypertension (high blood pressure)
High homocysteine levels
Obesity (excessive body weight)
High cholesterol (hyperlipidemia)

What Are The Potential Complications of Moyamoya Disease?

Those who develop moyamoya disease and ignore the primary symptoms and do not get treatment may also experience the following complications. Check some of them below:

Problems with speech and vision
Movement disorders
Brain damage
Paralysis
Stroke
Cognitive and psychological issues (including learning difficulties, memory loss, cognitive impairment, and others)
Surgery complications – Surgery used to restore blood flow to the brain carries some risks. For example, postoperative stroke, hyperperfusion syndrome, delayed wound healing, infections, and others.

This document does not contain a complete list of moyamoya disease complications. However, you can talk with your healthcare professional about ways to reduce the risk or even prevent them. Additionally, there is no way to prevent this disease, but you can take some steps to reduce the risk. For example, manage vascular risk factors, reduce the risk of atherosclerosis, quit smoking, and others.

Diagnosis

The diagnosis of almost all health conditions begins with a physical examination. Doctors will check for abnormalities linked to this disorder. However, to confirm or rule out moyamoya disease, they often perform the following tests. These include:

Cerebral arteriography – This test involves a catheter (a small and flexible tube with a lighted camera on the end) that is inserted into an artery in the arm or leg. Therefore, doctors will inject an iodine contrast dye into the bloodstream through this catheter to get detailed images on an X-ray scan. It often helps determine damaged or narrowed blood vessels.
MRA (magnetic resonance angiography) scan – This is another imaging test used to get detailed images of the blood vessels. It uses a magnetic field and radio waves to produce images.
MRI (magnetic resonance imaging) scan – This is a similar test to MRA, but it is used to get detailed images of organs and other structures inside the body. It often shows damage to the brain caused by moyamoya disease.

Stages of Moyamoya Disease

Generally, this is a progressive disorder that means it worsens over time. Once you are diagnosed with this disease, doctors will perform additional imaging tests to determine the extent (stage) of the condition. It often helps make the best treatment plan for you. To categorize this condition, doctors often use the “Suzuki” stages. For example:

1 stage – In people with the first stage, the condition affects only the carotid fork.
2 stage – In such cases, it affects all the terminal branches of the internal carotid artery. Usually, people begin to experience symptoms in this stage.
3 stage – This third stage of moyamoya disease occurs when it affects the deep blood vessels in the brain.
4 stage – It occurs when the blood vessels begin to regress.
5 stage – In this case, the transdural collateral vessels begin to appear on the angiogram.
6 stage – This is the end-stage of moyamoya disease, and it occurs when there is a complete narrowing or blockage of the internal carotid artery.

Treatment

Commonly, doctors prescribe the following medicines to treat moyamoya disease. For example:

Aspirin – This medicine is used to prevent blood clots.
Antiseizure medicines – This group of medicines is used to prevent seizures caused by moyamoya disease.
Anticoagulants (also called blood-thinners) – These medications are used to treat and prevent blood clots. However, anticoagulants carry some risks and doctors recommend them in certain cases only.
Calcium channel blockers – This group of medicines is not always recommended by doctors because they may increase the risk of a stroke. Generally, they are used to treat hypertension.

Usually, the previous medicines cannot stop the progression of moyamoya disease, and your physician may recommend a bypass surgery to treat the condition. It is used to:

Open narrowed blood vessels
Change the direction of the blood flow to the affected areas
Bypass blocked arteries by using normal scalp arteries as donor ones

Frequently Asked Questions

Is moyamoya disease genetic?

Some research has shown that people with moyamoya disease have a mutation (change) in the RNF213 gene. It is responsible for producing a protein that is involved in the development of blood vessels. Approximately 15% of people of Japanese descent with this disease have one or more biological family members with this condition.

What is the life expectancy of someone with moyamoya disease?

While early diagnosis and proper treatment may help people have a normal life expectancy, if this condition is left untreated, it can be fatal.

When should I go to the ER?

If you experience any of the following symptoms, immediately call 911 or go to the nearest emergency room (ER). These include:

Numbness on one side of the body
Sudden vision changes
Confusion
Severe headache
Walking problems

Ask your healthcare provider if you have additional questions.