Moyamoya

Background

MoyaMoya is a cerebrovascular disease characterized by progressive stenosis/occlusion of the arteries around the Circle of Willis.

The narrowing or blockage stimulates angiogenesis to provide collateral circulation to the brain.

On X-ray Angiography these small blood vessels give off a puff of smoke appearance also known as MoyaMoya in Japanese.

The disease is found more commonly in Asian countries and was first descried in Japanese literature in 1957.

There is mounting evidence there is a genetic cause of the disease.

Clinical Features

The developed collateral circulation is prone to bleeding, aneurysm, thrombosis exhibiting: focal neurological deficits, TIA, epilepsy, and bowl/bladder incontinence.

Children predominately exhibit ischemic strokes.

Approximately 2/3rd of children exhibit Electroencephalography (EEG) abnormalities: high voltage slow waves that occur during hyperventilation.

Can be associated with atherosclerosis, meningitis, vasculitis, autoimmune diseases, hematological conditions, brain tumors, and chromosomal abnormalities

Differential Diagnosis

Hemorrhagic stroke/Ischemic stroke

Giant cell arteritis/Vasculitis

Cranial trauma

Basilar Artery Thrombosis

Blood Dyscrasias

Cavernous Sinus Syndrome

Cerebral Aneurysms

Dissection Syndromes

Carotid atherosclerosis

Fibromusclar Dysplasia

Craniopharyngioma

Evaluation

Head CT and/or brain MRI are important studies to visualize infarctions and brain hemorrhages.

CT can show dilation of the sulci accompanies by focal ventricular enlargement.

MRI has higher sensitivity for detecting ischemic regions.

Magnetic Resonance Angiographic studies can demonstrate occlusions within the circle of Willis and better visualize the collateral vasculature. It is preferred over CTA in most institutions.