Which statement best describes Moyamoya disease in children, including diagnosis and treatment?

• A. Acute hemorrhagic stroke due to hypertensive crisis; diagnosed by CT; treated with antiplatelet therapy
• B. Progressive steno-occlusive intracranial vasculopathy with collateral networks; diagnosed by cerebral angiography or MR angiography; treated with revascularization surgery (direct or indirect bypass)
• C. Demyelinating disease of white matter; diagnosed by MRI; treated with steroids
• D. Genetic metabolic disease; diagnosed by metabolic panel; treated with enzyme replacement

Answer: (B)

Moyamoya disease in children is a progressive narrowing of the intracranial portion of the internal carotid arteries and proximal cerebral vessels, leading to the formation of fragile collateral networks that give a smoky appearance on angiographic imaging. This description captures the core features: the gradual stenosis of major intracranial arteries, and the compensatory collateral vessels that develop to try to maintain blood flow.

Diagnosis hinges on imaging that reveals both the arterial narrowing and the collateral networks. Cerebral angiography is the gold standard, while MR angiography can also identify the characteristic findings of stenosis with extensive collaterals. The treatment goal is to improve cerebral blood flow and reduce stroke risk, achieved most effectively through revascularization surgery. This includes direct bypass procedures that connect a donor artery to a recipient cerebral artery, as well as indirect bypass techniques that promote long-term development of new blood vessels.

Other statements describe conditions or management not typical of Moyamoya in children—such as an acute hemorrhagic stroke with hypertensive emergency diagnosed by CT and treated primarily with antiplatelets, a demyelinating white-matter disease treated with steroids, or a genetic metabolic disease treated with enzyme replacement. These do not align with the characteristic progressive steno-occlusive vasculopathy with collateral networks and surgical revascularization approach that define Moyamoya.