Stroke after adenotonsillectomy in patients with undiagnosed moyamoya syndrome.

IMPORTANCE: Moyamoya syndrome is a rare, occlusive cerebrovascular arteriopathy with significant risk for stroke. Populations that frequently undergo otolaryngologic procedures, including patients with Down syndrome and sickle cell disease, are particularly at risk for moyamoya. The initial presentation of moyamoya syndrome as stroke in the perioperative period of an otolaryngologic procedure has not been reported. OBSERVATIONS: A retrospective medical record review assessed the relationship of otolaryngologic operations and the onset of moyamoya symptoms. Moyamoya syndrome was present in 137 patients. Of these, 19 patients underwent otolaryngologic procedures; 3 children had strokes 2 to 4 days after adenotonsillectomy, including 2 children with Down syndrome. Intraoperative carotid artery injury was considered but was proven not to be the cause of stroke. Bilateral moyamoya disease was diagnosed in all 3 patients via vascular imaging studies; all subsequently underwent revascularization procedures. CONCLUSIONS AND RELEVANCE: Clinicians should be aware of an elevated prevalence of moyamoya syndrome in Down syndrome and sickle cell disease populations and should consider moyamoya syndrome in the differential diagnosis of postoperative stroke. Stroke risk is magnified in the perioperative setting related to perioperative dehydration and hypotension. Awareness and screening for cerebral vasculopathy in high-risk populations could prompt measures to decrease the occurrence of postoperative strokes after adenotonsillectomies.