Moyamoya disease

• Think “acute symptomatic seizures and stroke in an Asian patient”
• Chronic cerebrovascular condition
• Internal carotid artery or its terminal branches occlude progressively
• New vessels develop that bypass the stenotic arteries of the Circle of Willis, creating a rich network of small fragile arteries. This results in a dense angiographic appearance known as a “puff of smoke” and hence it’s translation as “moyamoya” in Japanese. Blood flow in the anterior and middle cerebral arteries are absent
• Rare 0.35 to 0.54 per 100 000 people in Asia, much lower in Western countries
• Youngest reported age: 2 months
• Female:Male::1.8:1.0 (less evident at younger ages)
• Mostly idiopathic; genetic origin may be present; 10% of patients have a family member with disease
• Also assoc with: NF1, Tris 21, fibromuscular dysplasia, congenital heart disease, cranial radiotherapy, intrathecal chemotherapy, sickle cell disease.
• Clinical presentation is age dependent
• Recurrent transient ischemic events; migraine-like headaches
• Children: ischemic stroke and seizures
• Adults: hemorrhagic stroke > ischemic stroke; rare seizures
• Dx
• History of acute neurologic deficits + “puff of smoke”
• MRI shows acute and chronic strokes
• MRI may be suggestive, but convential arterial arteriography is standard of dx
• Tx
• Drugs of of limited benefit (Steroids, Ca channel blockers, Anticoagulants, Antiplatelet drugs)
• Most promising tx is surgery: bypass between external and internal carotid systems; in children, indirect bypass is preferred via pial synangiosis
• Px
• Generally age related; younger = worse
• < 3yo: 53-58% favorable px
• > 6 yo: 86% favorable px

Arch Ped Adol Med. Feb 2009.