Autoimmune Glial Fibrillary Acidic Protein (GFAP) Astrocytopathy Presenting as Viral Encephalitis: A Case Report and Literature Review.

Glial fibrillary acidic protein astrocytopathy is a rare autoimmune condition characterized by antibodies against glial fibrillary acidic protein in astrocytes of the central nervous system. It can present with features of myelitis or meningoencephalitis. Diagnosis is based on the presence of serum or cerebrospinal antibodies against glial fibrillary acidic protein. Most cases respond to immunosuppressive therapy in the form of steroids. A 47-year-old woman with dizziness, tremors, and coryzal symptoms progressed over a period of a few weeks to develop clinical features of brainstem encephalitis. She was started on empirical antimicrobials and anti-convulsive therapy. Although initial MRI showed features of viral encephalitis, this was ruled out after CSF testing, and she was given high-dose methylprednisolone. She was admitted to the intensive care unit in view of her deteriorating level of consciousness. There was an excellent response to steroids, raising the probability of an autoimmune process, and she was extensively investigated over the next two weeks by a multidisciplinary team. Glial fibrillary acidic protein immunoglobulin G antibodies were detected in her serum and cerebrospinal fluid. She was started on a dose-tapering regimen of steroid and anti-convulsant medication along with rehabilitation therapy. She continues to make good progress. In conclusion, autoimmune glial fibrillary acidic protein astrocytopathy is a rare clinical entity that can be a diagnostic challenge. It's essential to consider this in the differentials of cases presenting with infectious meningoencephalitis to institute early immunosuppressive therapy and improve clinical outcome.