Neuromyelitis Optica Spectrum Disorder Initially Presenting With Meningitis-Like Symptoms: A Case Report.

We report a case of neuromyelitis optica spectrum disorder (NMOSD) relapse in a 45-year-old woman with a known 11-year history of NMOSD, who initially presented with meningitis-like symptoms, including fever, headache, and neck stiffness. Physical examination revealed neck stiffness and positive jolt accentuation, without any other neurological abnormalities. Cerebrospinal fluid (CSF) analysis revealed mononuclear-predominant pleocytosis and hypoglycorrhachia, raising concerns of meningitis. On hospital day 2, brain magnetic resonance imaging (MRI) revealed new hyperintense lesions in the right lateral midbrain and bilateral subcortical regions. That night, the patient developed acute right-sided visual impairment. The patient was diagnosed with NMOSD relapse and was treated with intravenous methylprednisolone pulse therapy, achieving gradual visual improvement. This case highlights that NMOSD can initially present with meningitis-like symptoms, and CSF profiles may resemble those of infectious meningitis. Clinicians should therefore maintain diagnostic vigilance for NMOSD in patients presenting with meningitis-like symptoms, particularly in those with a prior diagnosis of NMOSD or nonadherence to treatment.