A Case of Refractory Anti-GABAAR Encephalitis: Diagnostic Insights and Treatment Challenges.

A 59-year-old man developed olfactory dysfunction and behavioral changes that progressed to epilepsy. Brain magnetic resonance imaging (MRI) revealed multifocal cortico-subcortical T2-weighted fluid-attenuated inversion recovery (FLAIR) hyperintensities. Despite repeated plasmapheresis and immunotherapy with methylprednisolone, azathioprine, and cyclophosphamide, the response was limited. Follow-up MRI demonstrated recurrent cortical and subcortical lesions, sparing the brainstem, cerebellum, and basal ganglia. Gamma-aminobutyric acidA receptor (GABAAR) antibodies were subsequently detected in both serum and CSF, thus confirming the diagnosis. Anti-GABAAR encephalitis is an autoimmune disease characterized by refractory seizures and multifocal brain lesions. Multifocal lesions restricted to the cerebral hemispheres, sparing the brainstem, cerebellum, and basal ganglia, may suggest anti-GABAAR encephalitis.