MMD

Moyamoya Disease (MMD) is a rare, progressive cerebrovascular disorder characterized by the narrowing and blockage of the carotid arteries in the skull and the development of a network of tiny blood vessels that form to compensate for the blockage. This condition can lead to a stroke or transient ischemic attack (TIA), especially in children, though it can also affect adults. The name "Moyamoya" is derived from a Japanese term meaning "puff of smoke," which describes the appearance of the tangle of tiny vessels formed to compensate for the blockage.

Symptoms and Diagnosis

Symptoms of Moyamoya Disease vary depending on the individual and the stage of the disease. They may include headache, seizure, weakness, numbness or paralysis in the face, arm, or leg, typically on one side of the body, visual disturbances, and difficulties with speaking or understanding language. In children, the first symptom is often a stroke or recurrent TIAs, while adults may also experience bleeding in the brain (hemorrhagic stroke) due to the abnormal vascular networks.

Diagnosis of Moyamoya Disease involves a combination of clinical evaluation and imaging studies. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) are commonly used to visualize the structure of the brain and the blood vessels. In some cases, a conventional angiogram may be performed to provide a detailed view of the blood vessels in the brain.

Treatment

Treatment for Moyamoya Disease is primarily surgical. The goal of surgery is to bypass the blocked arteries and restore blood flow to the affected areas of the brain. The most common surgical procedures are direct and indirect revascularization techniques. Direct revascularization, such as the superficial temporal artery to middle cerebral artery (STA-MCA) bypass, involves connecting a scalp artery directly to a brain artery. Indirect revascularization methods, such as encephaloduroarteriosynangiosis (EDAS), involve laying a scalp artery on the surface of the brain to encourage the development of new blood vessel networks over time.

Epidemiology

Moyamoya Disease is most commonly diagnosed in Japan, Korea, and other East Asian countries, but it has been identified in patients worldwide. The disease tends to present in two peak age groups: children around 5 years of age and adults in their 40s. It is more common in females than in males.

Prognosis

The prognosis for individuals with Moyamoya Disease varies. Without treatment, the disease can lead to progressive neurological decline due to repeated strokes. However, with appropriate surgical intervention, many individuals can lead relatively normal lives, although they may continue to have some neurological deficits.

Research

Research on Moyamoya Disease is ongoing, with studies focusing on the genetic aspects of the disease, improvements in surgical techniques, and better understanding of the disease's natural history and optimal management strategies.