What is the main feature of Moyamoya disease?

Moyamoya disease is characterized primarily by the progressive stenosis (narrowing) of the internal carotid arteries and their proximal branches, particularly affecting the anterior and middle cerebral arteries. This narrowing leads to the formation of collateral vessels that are small and tangled, which is what creates the "moyamoya," a Japanese term meaning "hazy fog." This pathology often results in decreased blood flow to the brain, particularly affecting areas like the basal ganglia and resulting in ischemic strokes or transient ischemic attacks.

The key feature here is the blocked arteries in the basal ganglia, which directly contributes to the symptoms associated with the disease, such as strokes and neurological deficits, due to insufficient blood supply to critical brain regions. Understanding this feature is essential, as it informs treatment strategies and the overall management of patients with Moyamoya disease.