Moyamoya Disease

What is Moyamoya Disease?

The clinical term “moyamoya disease” refers to a chronic and progressive condition of the arteries in the brain. This condition means a rare blood vessel disorder where the carotid artery that supplies blood to the brain gets blocked. This will reduce the flow of blood to the brain and increase your risk of having a stroke.

Moyamoya disease commonly affects children, but adults also affected by this condition. This disease mostly found all over the world, but more prevalent in East Asian countries, especially Korea, Japan, and China. Certain genetic factors in those populations may responsible for developing this disease. Many children with moyamoya disease may also develop another medical condition like sickle cell disease, Down syndrome, congenital heart disease, and neurofibromatosis (NF).

The causes of moyamoya still not fully understood. Scientists believe that several factors ranging from genetic defects to traumatic injury may aggravate this condition. A recent study shows that about 10% of moyamoya case results from specific genetic mutations. The variation in the RNF213 gene on the long arm of chromosome 17 (17q25) helps to develop moyamoya disease in children. These conditions occur more often in women than in men ¹.

Although, moyamoya disease may occur at any age, but symptoms frequently seen between two peak incidence periods – between five and ten years of age in children, and between the ages of 30 to 50 years in older. First symptoms of moyamoya include stroke or recurrent transient ischemic attack (TIA), especially in children. Adults may also experience the same. In Japan, this condition affects about 1 per 300,000 people ².

Other common signs and symptoms include headache, seizure, nausea, vomiting, weakness, vision problem, speaking difficulties, numbness, or paralysis in the face, arm, or leg. Your children needs immediate treatment after showing any of those symptoms, as these are the warning signs of a brain hemorrhage ³.

How do Neurosurgeons Diagnose Moyamoya Disease?

Diagnosis of moyamoya includes reviewing your symptoms and your family and medical history by your doctor. Your physician will perform a physical examination and do some tests to be sure about this disease. The ideal test for diagnosing moyamoya includes a cerebral angiogram. This angiogram helps to produce a map of your child’s carotid arteries to see any abnormalities. During this angiogram, your doctor inserts a long tube into a blood vessel in your groin and guides it to your brain using X-ray imaging. Later than, he may inject a dye to view your vessels.

Depending on the specific symptoms, your doctor will perform more extensive testing. Other tests include ⁴:

1. Magnetic resonance imaging (MRI): This technique uses magnets and radio waves to create detailed images of the patient’s brain. Your doctor may inject a dye to view your vessels and see the blood circulation.
2. Computerized tomography (CT) scan: This also uses X-rays to create a detailed image of the patient’s brain.
3. Electroencephalogram (EEG): EEG observes the electrical activity of your brain and children with moyamoya disease will exhibit abnormal electrical response.

How do neurosurgical specialists treat Moyamoya Disease?

Treatment of moyamoya disease depends on the clinical presentation of the lesions. Doctor will evaluate your condition and determine the best treatment protocol according to your condition. Treatment protocol may include ⁵:

1. Medication

Several medications help to reduce the symptoms of the patient such as seizure, headache, etc. To prevent stroke, your doctor may prescribe a blood thinner like aspirin. Calcium antagonists such as verapamil also alleviate symptoms like headaches, helps to lower the blood pressure, and reduce the risk of transient ischemic attacks.

2. Surgery

Your doctor will consider the surgical option to fix the narrowed arteries in the brain. Surgery will decrease the risk of stroke by bypassing the narrowed artery. This creates a new blood supply for the affected areas of the brain. Most preferable surgical techniques include Pial synangiosis, Encephalomyosynangiosis (EMS), Encephaloduroarteriosynangiosis (EDMS), Dural inversion, etc.

References

1. Gosalakkal, J. A. Moyamoya disease: A review. Neurol. India 50, 6–10 (2002).
2. Khoo, S. T., Lim, G. & Lee, H. Y. ‘A case report of Moyamoya disease’. Singapore Med. J. 16, 315–317 (1975).
3. Joarder, M. & Chandy, M. MoyaMoya Disease in a Child: a Case Report. Pulse 6, 62–65 (2014).
4. Jeon, J. P. & Kim, J. E. A recent update of clinical and research topics concerning adult moyamoya disease. J. Korean Neurosurg. Soc. 59, 537–543 (2016).
5. Zhang, H., Zheng, L. & Feng, L. Epidemiology, diagnosis and treatment of moyamoya disease (Review). Exp. Ther. Med. 1977–1984 (2019) doi:10.3892/etm.2019.7198.