Autoimmune encephalitis in pediatrics: Fifteen-yearlongitudinal study at HNERM, Lima - Peru 2009-2024

Abstract

Objective: To describe the clinical-laboratory, neurophysiological and neuroimaging spectrum of pediatric patients diagnosed with autoimmune encephalitis (AIE), as well as the evolution and prognosis after intervention with the administration of standard immunomodulatory treatment. Materials and methods: This is a longitudinal, descriptive, and observational study, carried out in the Clinical Specialties Pediatric Service (SPEC), at HNERM, Lima – Peru, in the period 2009-2024. The identification of the cases was carried out, the follow-up of both the prodromal symptoms, the course of the clinical, laboratory, imaging and neurophysiological symptoms was carried out, as well as confirmation through anti-neuronal surface antibody (AANS) studies. AIE were characterized as clinically probable, definitive or confirmed, following the Graus and Celluci diagnostic criteria. The isolation of antibodies from CSF/serum was carried out using the hekw293 cell technique, as well as the determination of antibodies, by
immunocytochemistry and enzyme-linked immunosorbent assay (ELISA), in the Laboratory of the University of Pennsylvania, and the Hospital Clinic Barcelona (Dr. Dalmau). Results: Of the total number of admission diagnoses, 342 patients were admitted to the SPEC for demyelinating
and inflammatory conditions of the central nervous system (CNS). Of these, 98 patients were diagnosed as AIE, in 24 patients anti-neuronal surface antibodies were isolated: the anti NMDA-R antibody was confirmed in 21 patients, corresponding to 21.4%. The other reported antibodies were GluR5, GABA A, and anti-neuropil, in one patient each one. Conclusions and recommendations: EAI is a prevalent condition that puts the pediatric population at risk. A clinical picture of subacute encephalopathy plus subtle orolingual movements or dystonic postures may be indicative of assuming the patient has probable AIE and starting early treatment.