Unveiling the Uncommon: Glial Fibrillary Acidic Protein Autoimmune Meningitis with Myelitis Mimicking Infectious Etiologies.

A 25-year-old previously healthy female presented with a week-long history of headache, fever, bilateral lower limb weakness, and urinary retention. Initial examination and investigations pointed toward an infectious cause, with magnetic resonance imaging (MRI) suggestive of leptomeningitis with myelitis, and cerebrospinal fluid (CSF) analysis revealing lymphocytic pleocytosis and a low glucose ratio. Empirical treatment for meningoencephalitis was initiated, including broad-spectrum antibiotics and high-dose steroids for myelitis. A diagnosis of glial fibrillary acidic protein (GFAP) autoimmune meningitis was confirmed by positive GFAP antibody titers. The patient showed significant recovery following immunosuppressive therapy and was discharged from the intensive care unit (ICU). This case underscores the importance of a multidisciplinary approach, prompt intervention, and the role of autoimmune testing in atypical presentation.