Moyamoya disease is a very rare blood vessel disorder, where the carotid artery in the skull becomes blocked or narrowed, which reduces the blood circulation to the brain. To counteract this, tiny blood vessels originate at the base of the brain to supply the brain with blood. This condition may lead to ministroke, stroke or bleeding in the brain. It can also affect the functioning of the brain which causes cognitive and developmental delays. Moyamoya mostly affects children, but adults may also have the disorder. Though prevalent across the globe, it’s more common in East Asian countries due to certain genetic factors in those populations.
This disorder may develop at any age; however, symptoms commonly develop between 5 and 10 years of age in kids and between 30 and 50 years of age in adults. The disease causes different symptoms in adults and children, while in children, the first symptom is a stroke or recurrent transient ischemic attack. Though adults may experience these symptoms, they also experience bleeding in the brain (haemorrhagic stroke) from abnormal brain vessels. Recognising symptoms early is crucial to avert serious complications.
Some of the signs and symptoms due to reduced blood flow to the brain include:
- Weakness, or paralysis in the face, arm, or leg, typically on one side of the body
- Visual issues
- Difficulties with speaking or understanding others (aphasia)
- Cognitive delays
- Involuntary movements
These symptoms can be set off by exercise, crying, coughing, straining or a fever.
The exact cause of this neurological disorder is still unknown. Scientists believe that a higher prevalence in Asian countries strongly indicates a genetic predisposition in some populations.
At times, vascular alterations can happen that mimic moyamoya disease but may have different causes and symptoms and it is known as moyamoya syndrome.
Further, this syndrome is also related to certain disease conditions like Down syndrome, sickle cell anaemia, neurofibromatosis type 1 and hyperthyroidism.
Complications from moyamoya disorder are related to the effects of strokes such as seizures, paralysis, and vision issues. Speech problems, movement disorders and developmental delays are some of the other complications. In a few cases, the disorder can result in serious and permanent brain damage.
The healthcare professional may suggest certain diagnostic procedures and tests to confirm moyamoya disease. The neurologist will review the symptoms of the patients, collect medical history, and perform a physical assessment. Several tests are required to diagnose the condition and tests include:
Magnetic Resonance Imaging (MRI):
This test uses strong magnets and radio waves to get a detailed image of the brain. A dye is injected into a blood vessel to view arteries and veins and highlight blood flow. A perfusion MRI is recommended by the doctor if available, as this type of imaging can accurately measure the amount of blood passing via the vessels.
Computerized Tomography (CT) Scan:
This scan uses a sequence of X-rays to get a detailed image of the brain.
The doctor inserts a thin catheter into a blood vessel in the groin and guides it to the brain using X-ray imaging.
Positron Emission Tomography (PET):
In this test, a small amount of radio safe material is injected, and emission detectors are placed over the brain which provides visual images of brain activity.
This test checks the electrical activity in the brain via a series of electrodes attached to the scalp. Children with this disorder often exhibit abnormalities on EEG.
Transcranial Doppler Ultrasound:
In this procedure, sound waves are used to get images of the head and neck. Doctors use this test to determine blood flow in the blood vessels in the neck.
Doctors will assess the condition of the patient and determine the most appropriate treatment. Though treatment cannot cure the disorder but may be very effective in averting strokes. The main goal of treatment is to mitigate symptoms, improve blood circulation and lower the risk of severe complications.
Treatment options include:
Medications: Medicines are prescribed by the doctors to manage symptoms, to lower the risk of stroke or to support seizure control, including blood thinners, calcium channel blockers and anti-seizure medications.
Surgery: Prompt surgical treatment may help to slow the progression of the disease. If a patient develops symptoms or strokes or if tests show evidence of low blood flow to the brain, then the doctor may suggest revascularization surgery. In this procedure, surgeons bypass blocked arteries by connecting blood vessels on the outside and inside of the skull to restore blood flow to the brain. This may include direct or indirect revascularization procedures or a combination of both.