Pediatric anti-CaVα2δ autoimmune encephalitis: A case report and literature review.

Anti-voltage-gated calcium channel alpha-2/delta subunit (anti-CaVα2δ) encephalitis is a rare autoimmune encephalitis (AE), with only two cases of anti-CaVα2δ AE have been reported in the literatureto date. The clinical characteristics and prognosis of this rare AE need to beexpanded.We present the case of a 9-year-oldgirl, who initially presented with fever and lymphadenitis, which progressed to headaches, drowsiness, frequent seizures, cognitive impairment, memory loss, and involuntary movements. Brain magnetic resonance imaging revealed lesions in the bilateral external capsule. Moreover, anti-CaVα2δ antibodies were detected (1,30) 3 and 5 weeks after symptom onset. Video electroencephalography revealed slow, severely diffuse, background activity with multifocal epileptiform discharges. Although the patient was administered a combined immunotherapy consisting of intravenous immunoglobulin, intravenous methylprednisolone, and rituximab, sheexhibited persistent neurological sequelae at the last follow-up (Modified Rankin Scale score of 4; Pediatric Quality of Life Inventory score of 75). Whileour case shares similar clinical characteristics with previously reported anti-CaVα2δ AE cases, our patientwas unresponsive to immunotherapy and experienced severe neurological sequelae during follow-up. This report broadens the clinical phenotype and prognosis associated with this rare condition, providing further information and clinical insights for the management of future cases.