Autoimmune glial fibrillary acidic protein astrocytopathy mimics infectious meningitis: Two case reports

•As a newly defined disease, A-GFAP-A has a variety of clinical manifestations and more attention is needed.•In our cases, the patients presented mainly with fever, headache, nuchal rigidity, pleocytosis and decreased glucose level in CSF, and which mimic a CNS infection. So, it's of important meaning to differentiate them in clinical work.•The authors have contributed some helpful tips in differentiation between these two diseases. Autoimmune glial fibrillary acidic protein astrocytopathy (A-GFAP-A) has been recently characterized as a novel autoimmune central nervous system (CNS) disorder with GFAP antibody as the biomarker. However, nonspecific symptoms of A-GFAP-A contribute to misdiagnosis. The patients presented with initial symptoms of fever, headache, and nuchal rigidity. Case 1 exhibited mild signs of irritability, active tendon reflexes, and dysuria; case 2 had transient loss of consciousness. Cerebrospinal fluid (CSF) revealed lymphocytosis, elevated protein level, and decreased glucose level. Magnetic resonance imaging (MRI) revealed radial gadolinium enhancement perpendicular to the lateral ventricle. Viral meningitis or tubercular meningitis was suspected. However, their inflammatory and pathogenic indicators showed no abnormal changes, and empirical antibiotic and antiviral drugs did not result in remarkable recovery. Subsequently, cases were detected with a strongly positive expression of GFAP antibody in CSF and the symptoms improved dramatically after high-dose methylprednisolone pulse treatment. A-GFAP-A with meningitis-like symptoms could initially masquerade as intracranial infection, and prompt detection of GFAP antibody is essential for differentiation.