What is Moyamoya Disease?
Moyamoya disease occurs when the carotid artery in the brain narrows and/or closes. When this happens, tiny blood vessels around the base of the brain try to compensate by opening up and attempting to supply blood to the part of the brain on the other side of the blockage. These small blood vessels are known as moyamoya vessels.
While moyamoya blood vessels try to restore proper blood flow, they are ineffective. Inadequate blood flow to the brain results in many different neurological symptoms. These symptoms are the result of the brain not having access to the oxygenated blood it needs.
Moyamoya disease can affect anyone of any age, but it is more common in two populations: those between ages 5 and 10 and those between ages 30 and 50. Other risk factors for the condition include Asian descent, a family history of moyamoya disease and female sex, along with the presence of other medical conditions such as sickle cell anemia or Down syndrome.
Symptoms of Moyamoya Disease
Symptoms of moyamoya disease vary somewhat depending on the affected patient’s age. Children who have the condition typically experience symptoms related to reduced blood supply in the brain.
Adults with moyamoya disease, on the other hand, are more likely to experience intracranial hemorrhage caused by the rupture of moyamoya vessels. This is thought to be due to the fact that adults typically have higher blood pressure than children.
Symptoms of moyamoya disease may include:
- Blurry or poor vision
- Inability to move extremities
- Intracranial bleeding
- Speech difficulties
- Strokes or ministrokes
- Uncontrolled movements
How Moyamoya Disease Is Diagnosed
If a doctor suspects symptoms related to moyamoya disease, he or she will first review the symptoms and overall health of the patient, including personal and family medical history. From there, the doctor will conduct a physical examination, with close attention paid to areas of the body affected by symptoms.
To confirm a diagnosis of moyamoya disease, the doctor will also order imaging tests to visualize the blood vessels in the brain. These tests may include MRI, CT, cerebral arteriography and/or electroencephalography.
Treatment for Moyamoya Disease
If diagnosed with moyamoya disease, treatment will vary depending on individual circumstances. A doctor will consider the severity of the symptoms as well as the risk of stroke before recommending a treatment plan.
Treatment for moyamoya disease is used to mitigate individual symptoms of the condition and to lower the risk of developing severe complications, such as stroke.
In many cases, medications are the first-line treatment for moyamoya disease. Medication therapy for the condition may include blood thinners, calcium channel blockers and/or anti-seizure medications, with the intention of limiting seizures and lowering the risk of stroke.
When moyamoya disease is severely impacting blood flow to the brain, a provider may recommend surgery. Revascularization surgery is used to restore blood and oxygen flow.
There are two main types of revascularization surgery — direct revascularization, where a scalp artery is stitched to the brain artery to immediately increase blood flow, and indirect revascularization, through either encephaloduroarteriosynangiosis or encephalo-myo-synangiosis.
Both procedures involve the restoration of oxygenated blood flow to the brain, but they differ in how that’s accomplished. During encephaloduroarteriosynangiosis, a scalp artery is removed and then attached to the surface of the brain, which allows blood vessels to grow into the brain over time. During encephalo-myo-synangiosis, a muscle is removed from the forehead and placed on the surface of the brain, which helps restore blood flow.