A Missed Case of Area Postrema Syndrome Presenting with Neuromyelitis Optica Spectrum Disorder.

BACKGROUND Neuromyelitis optica spectrum disorder (NMOSD), which is also known as Devic disease, is a chronic disorder of the brain and spinal cord that includes inflammation of the optic nerve and spinal cord. Area postrema syndrome (APS) is due to involvement of the bulbar emetic reflex center, and has previously been described in NMOSD. Patients with APS may present with nausea, vomiting, or hiccups. This report is of a 33-year-old Asian American woman with history of APS who presented with NMOSD. CASE REPORT A 33-year-old Southeast Asian woman, 2 months postpartum, presented with fever, hypersomnolence, altered mental status, and difficulty ambulating. Neurological examination revealed a lethargic woman with poor attention span, broad-based gait ataxia, and positive Romberg's sign. Laboratory work-up showed sodium 123 milliequivalent/L (mEq/L). Brain magnetic resonance imaging (MRI) with contrast revealed bilateral, non-enhancing, patchy fluid-attenuated inversion recovery (FLAIR) hyperintensities in the anteroinferomedial thalamus extending to the mammillary bodies. Additional history revealed hospitalization for intractable nausea, vomiting, and hiccups 2 years ago. NMOSD was confirmed with positive AQP-4 antibody, prompting treatment with intravenous (i.v.) methylprednisolone, followed by plasmapheresis. Repeat brain MRI showed mild improvement of bilateral thalamic FLAIR hyperintensities and no clinical recurrence was reported with Rituximab treatment. CONCLUSIONS This case highlights the importance of the diagnostic diligence required for NMOSD diagnosis. Multiple etiologies can mimic the clinical presentation of acute diencephalic syndrome; thus, a broad differential needs to be considered. This report presents the diagnostic work-up and management of a patient with a complex neurological condition that was diagnosed as NMOSD.