First Pediatric Case of Autoimmune Encephalitis Associated With COVID-19 in Costa Rica.

Very few COVID-19-associated autoimmune encephalitis cases have been documented in children. This case report focuses on a previously healthy four-year-old girl who presented to the emergency room of the National Children's Hospital in Costa Rica in a postictal state due to a tonic-clonic seizure that progressed to status epilepticus. She had no previous history of fever or associated trauma. She was considered severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive by epidemiological linkage four weeks prior to the event, and her immunoglobulin G (IgG) levels for SARS-CoV-2 were positive. She presented with generalized decrease in muscle strength, she couldn't even walk, also dyskinetic movements in upper extremities, language impairment, frequent seizures, retrograde amnesia, and orolingual dyskinesias. An extensive diagnostic workup was performed, including bacterial and viral panel in cerebrospinal fluid, however the only positive result was the IgG for SARS-CoV-2. Electroencephalogram (EEG) and magnetic resonance imaging (MRI) findings were compatible with autoimmune encephalitis.  An antibody panel was performed, which was negative in cerebrospinal fluid and positive for anti-gamma-aminobutyric acid (GABA)/b1 in serum. She received three antiseizure drugs, plasmapheresis, intravenous gamma-globulin, methylprednisolone, and rituximab, which partially improved her condition. She currently has refractory epilepsy, memory problems, loss of language skills, and neuropsychiatric dysfunction. To our knowledge, this is the first case of autoimmune encephalitis secondary to SARS-COV-2 infection in a pediatric patient in Costa Rica.