Moyamoya disease is a rare, progressive neurological disorder caused by blocked arteries at the base of the brain. Moyamoya disease often goes undiagnosed for many years, as its symptoms can be mistaken for other conditions. There is currently no cure for moyamoya disease, but there are treatments available that may help manage the symptoms and improve quality of life.
Moyamoya disease is most commonly diagnosed in children and young adults, but it can occur at any age. The cause of moyamoya disease is unknown, but it is believed to be the result of a combination of genetics and environmental factors. There is no specific test for moyamoya disease, so diagnosis is often made through a process of elimination. Treatment for moyamoya disease typically includes medication to prevent blood clots, surgery to improve blood flow to the brain, and rehabilitation therapy. While there is no cure for moyamoya disease, treatment can help improve the quality of life and prevent serious health problems for people affected. Early diagnosis and treatment are key to managing moyamoya disease and preventing serious health issues.
What Is Moyamoya Disease?
Moyamoya condition is a progressive and chronic disease of the arteries in an individual’s brain. This condition causes the narrowing of blood vessels, which frequently lead to blockages. These blockages may subsequently lead to seizures, hemorrhagic strokes, and ischemic strokes. Moyamoya condition is most typically diagnosed in children from ages 10-14, or in adults over the age of 40.
The name “moyamoya” stems from the Japanese word meaning a hazy puff of cloud or smoke. In individuals suffering from moyamoya disease, their blood vessels appear this way in a brain scan called an angiogram.
Moyamoya disease differs from another condition known as moyamoya syndrome. Blood vessels appear radiographically similar in moyamoya syndrome, but the narrowing is caused by different mechanisms than the genetic mutations that lead to moyamoya disease.
Though moyamoya disease happens all over the world, it is more common in areas such as China, Japan, and Korea. This possibly has to do with genetic factors in these populations.
Moyamoya Symptoms and Diagnosis
Moyamoya disease symptoms can differ from person to person and can often be mistaken for other conditions. Some common moyamoya disease symptoms include:
- Vision problems
- Weakness or numbness in the arms or legs
- Memory problems
- Visual disturbances
- Recurrent transient ischemic attacks are also known as TIAs or mini-strokes.
- Strokes: ischemic strokes due to blockages or hemorrhagic strokes due to bleeding.
- Hemiparesis: paralysis or weakness in one side of the body.
- Difficulty remembering, focusing, or thinking clearly due to consistent and frequent strokes and bleeding.
- Difficulties with understanding or speaking
- Involuntary movements
Moyamoya disease causes different symptoms in adults than it does in children. In children, some of the first signs are strokes or transient ischemic attacks. Adults may also experience these symptoms, but they will also often have bleeding in the brain, or a hemorrhagic attack, from brain vessels.
Moyamoya disease is often diagnosed by a neurologist using tests such as the following:
- Computerized tomography (CT) scan. A CT scan uses a series of X-rays to create a detailed image of a patient’s brain. It is common practice for a doctor to inject a dye into a blood vessel to highlight blood flow in the arteries and veins (CT angiogram). This test is not able to diagnose the early stages of moyamoya disease, but may still be helpful in identifying abnormal blood vessels.
- Magnetic resonance imaging (MRI). An MRI uses powerful magnets and radio waves to create detailed images of the brain. It is common for a doctor to inject dye into a blood vessel to get a better view of the arteries and veins and highlight blood circulation (magnetic resonance angiogram). A doctor may recommend a perfusion MRI if available, which is a type of imaging that can measure the amount of blood passing through the vessels and how critical the reduction of blood supply to the brain is.
- Cerebral angiogram. In this procedure, a doctor inserts a long, thin tube (catheter) into a blood vessel in the groin and guides it to the brain by using X-ray imaging. The doctor proceeds to then inject dye through the catheter into the blood vessels of the brain. The contrast conforms to the shape of the blood vessels to make them more visible under X-ray imaging.
- Positron emission tomography (PET) scan or single-photon emission computerized tomography (SPECT). In these tests, the patient is injected with a small amount of safe radioactive material and places emission detectors over the brain. PET gives visual images of brain activity. SPECT measures blood flow to various regions of the brain.
- Transcranial Doppler ultrasound. In surgical transcranial Doppler ultrasound, sound waves are used to obtain images of the head and sometimes the neck. Doctors may use this test to evaluate blood flow in blood vessels in the neck.
- Electroencephalogram (EEG). An EEG monitors the electrical activity in the patient’s brain by the manner of a series of electrodes attached to the scalp. This is usually the best way to diagnose children, as children with moyamoya disease often exhibit abnormalities on EEG.
Moyamoya Disease Causes and Risk Factors
Moyamoya disease is a result of a number of different genetic mutations. These mutations lead to the formation of abnormal blood vessels in the brain. These vessels are not as strong and can easily become blocked, leading to a number of different health problems.
While moyamoya disease has a genetic component, it is not just passed down from parents to children. Environmental and lifestyle factors may also play a role in causing moyamoya disease.
There is still much unknown about the causes of moyamoya disease, and more research is needed to determine all the factors that contribute to its development.
There are a number of moyamoya disease risk factors that can increase an individual’s chance of developing the condition. Some of these risk factors include:
- High blood pressure
- Race: moyamoya disease is more common in certain populations, such as those from China, Japan, and Korea
- Age: moyamoya disease can occur at any age, but is most often seen in children between the ages of 10-14 and in adults between the ages of 40 and 60
- Sex: moyamoya disease is more common in females than males
- Pregnancy: there is a small increased risk of moyamoya disease during pregnancy
- Traumatic brain injury: moyamoya disease can develop after a traumatic brain injury
There are also some risk factors that are still being studied and are not yet fully understood. More research is needed to determine all the causes of moyamoya disease.
Moyamoya Disease Treatment and Prevention
There is currently no cure for moyamoya disease, but there are a number of treatment options that can help to improve the patient’s quality of life.
The main goal of treatment for moyamoya disease is to prevent any blockages in the blood vessels and maintain blood flow to the brain. This can be done through a number of different methods, including:
- Medications: Medications can be used to help improve blood flow to the brain and prevent any blockages from forming. Medications include:
+ Blood Thinners: this helps prevent strokes.
+ Calcium channel blockers: this medication, also known as calcium antagonists, proves helpful in managing headaches and may reduce symptoms related to transient ischemic attacks. These medications also manage blood pressure, which helps prevent blood vessel damage.
+ Anti-seizure medications.
- Surgery: Surgery is often needed to widen the blocked or constricted blood vessels in the brain.
- Rehabilitation: rehabilitation may be necessary to help improve the patient’s speech, movement, and overall function.
There are a number of different surgical procedures that can be used to treat moyamoya disease. The most common surgery is called a “revascularization” surgery. This surgery involves widening the blocked or constricted blood vessels in the brain. There are a number of different revascularization surgeries that can be performed, depending on the individual’s needs.
Another type of surgery that can be used to treat moyamoya disease is called a “craniotomy.” In this surgery, the surgeon makes an incision in the skull and removes a portion of the bone to access the brain. This surgery is often used to treat patients who have had a traumatic brain injury.
Rehabilitation is also an important part of treatment for moyamoya disease. Rehabilitation may be necessary to help improve the patient’s speech, movement, and overall function. Moyamoya Disease Prognosis.
The prognosis for moyamoya disease varies from patient to patient. Some patients may only experience a few minor problems, while others may experience more severe health complications.
There is currently no known way to prevent moyamoya disease from developing, but there are a number of things that can be done to reduce the risk of developing the condition:
- Maintaining a healthy lifestyle: Eating a healthy diet and exercising regularly is significant for maintaining overall health and reducing the risk of developing many diseases, including moyamoya disease.
- Controlling blood pressure: High blood pressure can damage blood vessels and increase the risk of developing moyamoya disease. Controlling blood pressure through diet, exercise, and medication can help to reduce this risk.
- Avoiding smoking and alcohol: Smoking and alcohol abuse can damage the body’s cells and increase the risk of developing many diseases, including moyamoya disease.