Area postrema syndrome in aquaporin-4-positive neuromyelitis optica spectrum disorder: clinical and imaging correlation: three case presentations

Abstract Background Area postrema syndrome (APS), characterized by persistent nausea, vomiting, and hiccups, is a distinctive but often under-recognized manifestation of neuromyelitis optica spectrum disorder (NMOSD). Owing to the absence of a blood–brain barrier and high aquaporin-4 (AQP4) expression, the area postrema is particularly susceptible to immune-mediated injury. Early identification of this entity is crucial, as APS may precede other classical manifestations of NMOSD. Aim To evaluate the clinical presentation and characteristic MRI findings of area postrema syndrome in aquaporin-4-positive neuromyelitis optica spectrum disorder, and to emphasize the importance of early radiological recognition in a three case series. Case series We report three patients with AQP4-IgG-positive NMOSD who presented initially with features of APS. Magnetic resonance imaging demonstrated characteristic T2/FLAIR hyperintensity involving the dorsal medulla at the level of the area postrema, with variable extension into the cervicomedullary junction, upper cervical spinal cord, and ventral medulla. All patients were negative for myelin oligodendrocyte glycoprotein antibodies. Acute management included high-dose intravenous methylprednisolone followed by oral corticosteroid tapering; one patient with suboptimal steroid response required therapeutic plasmapheresis. Long-term relapse prevention was achieved with rituximab therapy in all cases. Conclusion This case series highlights the importance of recognizing APS as an early clinical and radiological marker of AQP4-positive NMOSD. Careful evaluation of the dorsal medulla on MRI in patients presenting with unexplained persistent emesis can facilitate timely diagnosis and initiation of appropriate immunotherapy, thereby improving clinical outcomes.