[A case of suspected neuromyelitis optica spectrum disorder preceded by aseptic meningitis-like symptoms].

A 20-year-old woman was hospitalized after experiencing headaches, high fever, and nausea for 1 week. She was conscious and had no abnormal neurological findings or neck stiffness. Examination of her cerebrospinal fluid showed a pronounced elevation of mononuclear cells. She was admitted to our hospital with the diagnosis of meningitis and had hypersomnia 3 days later. Brain MRI (FLAIR) demonstrated high-intensity lesions at the dorsal pons, and bilateral hypothalamus and spinal MRI demonstrated longitudinal T₂ high-intensity lesions extending from C2 to C4 and from C6 to Th6. We suspected neuromyelitis optica spectrum disorder (NMOSD) and administered intravenous methylprednisolone after which her symptoms and MRI abnormalities improved immediately. Serum anti-aquaporin-4 antibody and anti-myelin oligodendrocyte glycoprotein antibody were negative. Thus, it is important to perform MRI imaging early in the onset of aseptic meningitis due to numerous case reports of patients diagnosed with neuromyelitis optica or NMOSD with initial meningitis-like symptoms.