Postvaccinal GABA-B receptor antibody encephalitis after ChAdOx1 nCoV-19 vaccination.

Several cases of autoimmune encephalitis have been reported after ChAdOx1 nCoV-19 (AZD1222) vaccination. We encountered a male patient who presented with generalized tonic-clonic seizures, cognitive decline, and gait disturbance that occurred suddenly after the second dose of the ChAdOx1 nCoV-19 vaccine. Clinical presentation and magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) test results were compatible with limbic encephalitis. Synaptic autoantibody tests confirmed serum and CSF GABA B receptor antibodies were present. The patient was treated with immunotherapy with intravenous immunoglobulin and rituximab. This GABA-B receptor antibody encephalitis case occurred presumably due to transient autoantibody production following vaccine administration.