Autoimmune encephalitis due to anti-NMDA antibodies with neuropsychiatric presentation: case report

Abstract

Background: Encephalitis due to antibodies against the N-methyl-D-aspartate (NMDA) receptor has an incidence of 5-10/100,000 inhabitants per year. Due to its wide spectrum of neuropsychiatric manifestations, it can be confused with a psychiatric syndrome. Its etiopathogenesis has been associated with a history of infections and paraneoplastic processes, however, the presence of these is not essential to develop the disease. Clinical Case Description: The clinical case of a 17-year-old boy with a history of controlled epilepsy of 16 years of evolution that presents behavioral changes is presented, confusion, and hallucinations of 3 weeks of evolution, added to this a single tonic- clonic seizure, and state of agitation; reason why he is taken to the emergency service. Initially, it was managed as a psychotic syndrome with haloperidol at therapeutic doses. In subsequent evaluations, laboratory alterations of the CPK, alterations of movement, and consciousness were identified, for which reason neuroleptic malignant syndrome was suspected. The child with rapid, and progressive deterioration of his neurological status required attention in the Pediatric Intensive Care Unit (PICU) with ventilatory support, in addition, dysautonomia was evidenced due to which Autoimmune Encephalitis (AD) was suspected. Management with immunomodulators was started, showing good clinical evolution, and then the diagnosis was confirmed by means of positive anti-NMDA antibodies in CSF. Conclusion: AE against NMDA receptor is a rare entity that should be considered within the differential diagnoses of a psychiatric condition. Its late or erroneous diagnosis implies multiple neurological sequelae.