About Moyamoya Disease

Overview

Moyamoya disease is a rare cerebrovascular disorder characterized by the progressive blockage of arteries at the base of the brain, specifically in the basal ganglia area. The term "moyamoya" comes from Japanese and refers to the tangled appearance of tiny blood vessels that develop as a to compensate for the blockage. This condition primarily affects children but can also occur in adults. The initial symptom in children is often a stroke or recurrent mini-strokes (transient ischemic attacks) accompanied by muscle weakness or paralysis on one side of the body. In adults, blocked arteries can lead to hemorrhagic strokes caused by bleeding into the brain. Moyamoya disease is more prevalent in Asian countries compared to Europe or North America. While the exact cause is unknown, it is believed to be related to increased blood vessel growth and may be associated with other underlying diseases.

Causes and Risk Factors

Moyamoya disease is a progressive cerebrovascular disorder characterized by blocked arteries at the base of the brain. While the exact cause is unknown, it is believed to be related to increased blood vessel growth and may be associated with other underlying diseases.

Non-modifiable risk factors of Moyamoya disease are factors that cannot be changed. These include:

• Genetic factors: Variations in certain genes, such as the RNF213 gene, have been found to be associated with the development of Moyamoya disease.
• Ethnic background: Moyamoya disease is more common in Asian countries (China, Japan, Korea)

Modifiable risk factors of Moyamoya disease are factors that can be influenced or changed. These include:

• Underlying conditions: These include conditions such as hypertension, diabetes, and high cholesterol levels, which can contribute to the progression of Moyamoya disease.
• Inflammatory factors: Chronic inflammation in the body has been suggested to play a role in the development and progression of Moyamoya disease.
• Metabolic factors: Imbalances in certain metabolic processes, such as alterations in circulating metabolites like branched-chain amino acids, have been implicated in the pathogenesis of Moyamoya disease.

It is important to note that while these risk factors have been identified, they may not fully explain all cases of Moyamoya disease. Further research is needed to better understand the underlying causes and risk factors associated with this condition.

Symptoms

The most common symptoms of Moyamoya disease include:

• Headaches
• Difficulties with speaking or understanding others
• Decline in cognitive function, including memory and thinking abilities
• Seizures
• Visual deficits
• Fainting or loss of consciousness
• Personality changes

As the disease progresses the following complications may arise:

• Hemorrhagic stroke: This is a type of stroke caused by bleeding in the brain.
• Ischemic stroke: This occurs when there is a decrease in blood flow to the brain due to narrowed or blocked blood vessels.
• Transient ischemic attacks (TIAs): These are temporary episodes of reduced blood flow to the brain, often referred to as "mini-strokes."

It's important to note that symptoms can vary between children and adults. If you suspect you may have Moyamoya disease or are experiencing any of these symptoms, it's crucial to seek immediate medical attention.

Diagnosis

To diagnose Moyamoya disease, several examinations, tests, and procedures may be performed:

• Physical examination: A healthcare provider will conduct a physical exam to look for any physical signs of the disease.
• Medical history review: The healthcare provider will review your symptoms and your family's medical history.
• Imaging studies: Various imaging tools can be used to visualize the blood vessels in the brain and measure blood supply, including:
  • Cerebral angiogram
  • Computed tomography (CT) scan
  • Magnetic resonance imaging (MRI)
  • Positron emission tomography (PET) scan
  • Transcranial Doppler ultrasound

It's important to consult with a healthcare professional who specializes in Moyamoya disease for accurate diagnosis and assessment of its stage or severity.

Treatment Options

The goals of treatment for Moyamoya disease are to improve blood flow to the brain, prevent strokes, and relieve symptoms. Here are the different types of treatments and how they work to achieve these goals:

• Surgical procedures: Surgery is the primary treatment for Moyamoya disease. Revascularization surgeries can open narrowed blood vessels or bypass blocked vessels, improving blood flow to the brain. These surgeries include:
• Direct bypass: A blood vessel from outside the skull is connected directly to a vessel inside the skull, bypassing the blocked or narrowed vessels.
• Indirect bypass: A blood vessel from outside the skull is placed on the surface of the brain, allowing new blood vessels to grow and provide additional blood flow.
• Combined bypass: Both direct and indirect bypass procedures are performed.
• Medications:
• Antiseizure medications: Prescribed if seizures occur.
• Blood thinners: Reduce the risk of stroke by preventing blood clots.
• Calcium channel blockers: Help reduce headaches and symptoms related to transient ischemic attacks (TIAs).
• Occupational or physical therapy: These therapies can help improve quality of life by enhancing developmental skills and physical function affected by a stroke.
• Health behavior changes:
• Engaging in regular exercise, a balanced diet, and not smoking can help reduce the risk of strokes.

It's important to note that specific treatment plans should be discussed with a healthcare professional as individual circumstances may vary. Medication dosing may be affected by many factors, so check with your healthcare professional about dosing for your individual situation. Other side effects can occur. Check with your healthcare professional or read the information provided with your medication for additional side effect information.