Intractable nausea and vomiting as an uncommon presentation in an anti-aquaporin 4-positive patient.

Autoantibodies targeting aquaporin 4 (AQP4) water channels are a sensitive and specific biomarker for neuromyelitis optica spectrum disorder (NMOSD). Presence of AQP4 antibodies distinguishes NMOSD from multiple sclerosis. We present our experience with an anti-AQP4 antibody-positive patient diagnosed with NMOSD who complained of intractable nausea and vomiting, not restricted to optic neuritis or acute myelitis during the first attack.