Moyamoya Disease

It is caused by blocked arteries at base of brain. The word “moyamoya”  implies “smoke puff”. It appears as a tiny vessels narrow and become blocked, which can result in stroke.

The cartiod artery is very large of which the pulses can be felt on both sides of neck. It starts at aorta and divides near larynx into external and internal carotid arteries. The external artery supply blood to face and scalp. Internal arteries supplies blood to front and side of brain.

What is moyamoya disease?

It is a chronic and progressive narrowing of internal carotid arteries at base of brain which divides in middle and anterior cerebral arteries. The walls of arteries become thick, which narrows the inside diameter of vessel. The narrowing result in complete block and stroke.

To reduce the narrow arteries, the brain create a collateral blood vessels in attempt to deliver rich-oxygen blood to the deprived areas of brain. These small vessels, when seen in angiogram looks hazy. In this condition,  the blood vessels are more weaker than normal blood vessels. The small collaterals can break and bleed, which can cause brain hemorrhage. The disease can affect front and side areas of brain.

The progression of the disease follow typical course and are as follows:

• Stage 1- Internal carotid arteries get narrowed.
• Stage 2- Development of any moyamoya vessels at the base of brain.
• Stage 3-Internal cartoid artery narrowing and moyamoya vessels gets intensified.
• Stage 4- Increased collateral vessels from scalp and minimizing moyamoya vessels.
• Stage 5- Narrowing of internal carotid artery and reductionof moyamoya vessels.
• Stage 6- The disappearance of moyamoya vessels, internal carotid artery is completely blocked.

Once the process of blockage begins, it continues. There is no medicine to reverse the effect. If had a major stoke or bleeding occurred, the patient will have permanent loss of function.

Symptoms

The symptoms include:

• Mini stroke.
• Ischemic stroke.

Causes

The real cause of moyamoya disease is not known. The inheritance can be a cause of the disease.

Diagnosis

If you are having symptoms like stroke, then you will be referred to neurosurgeon. The surgeon will check about the possibility of some symptoms, any medical problems, current medications ,family history. Physical exam, diagnostic tests like mri, ct scan, angiogram, etc. will also be performed. To confirm the diagnosis of moyamoya disease, an angiogram is required.

Surgery

The surgery is recommended for moyamoya patient with progressive TIAS or stroke. There are various kinds of surgeries available.

Cerebral bypass procedure: It is a method of revascularization. It involves connecting a blood vessel from the outside of brain to  inside vessel of brain, so that the reroute of blood flow around an artery which is blocked, damaged or narrowed. Most common bypass procedure is STA-MCA(Superficial Temporal Artery to Middle Cerebral Artery),this may help in instant improvement in the blood flow. If suppose, the superficial temporal artery is not available then another artery can be used.

EDAS(Encephalo Duro Arterio Synangiosis) procedure: It is a process of revascularization in which the superficial temporal artery is kept in contact with the surface of brain. A hole is made in skulljust below the artery. The artery is then stitched to the surface of brain and the bone replaced. After sometime, small arterial vessels form to the brain.

EMS(Encephalo Myo Synangiosis) procedure: It is a process in which the temporal muscle which is on side of the head is dissected, through an opening of skull and is placed onto the surface of brain. Then new vessels form between blood muscles and brain.

EDAMS (Encephalo Duro Arterio Myo Synangiosis) procedure: It is a combination of the technique of EDAS and EMS.