Acute Confusional State Revealing Moyamoya Disease in the Emergency Department: A Rare Entity.

A 54-year-old woman was admitted to the emergency department for an acute, fluctuating altered mental status and reduced perceptual awareness of her surroundings as well as disorganized thinking. Blood tests, including for drugs, were normal. A CT scan of the brain was normal. Magnetic resonance imaging and CT angiography of the supra-aortic vessels were both were consistent with moyamoya disease. The patient was hospitalized for further investigations. LEARNING POINTS: Moyamoya disease should be considered in the differential diagnosis of middle-aged patients presenting with an acute confusional state of unknown aetiology in the emergency department.The absence of focal examination findings does not exclude neurological disease as the cause of acute confusion, requiring further neuroimaging tests. © EFIM 2021.