Pediatric anti-NMDA receptor autoimmune encephalitis masquerading as depression: A case report from a tertiary care center in South India

Autoimmune disorders are now widely recognized as playing a larger role in encephalitis than previously thought. The most common disorder appears to be anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. Psychological symptoms, memory difficulties, and autonomic instability are all part of the complicated presentation and are being considered an important differential diagnosis for children presenting with acute behavioral disturbances. We present the case of a 17-year-old girl, who presented with a 1.5-year history of psychiatric symptoms such as pervasive low mood, decreased ability to concentrate on her studies, academic decline, memory disturbances along with poor social interaction, decreased self-esteem, and ideas of guilt. This was accompanied by altered biological functions. Within a week, the symptoms changed dramatically, with labile mood, over familiarity, over identification, déjà vu, auditory hallucinations and anxiety symptoms, nonspecific somatic symptoms such as fever, vomiting, and neurological symptoms including seizures and dyskinesia. Diagnosis of anti-NMDAR encephalitis was made by electroencephalography and serum antibody testing. Symptom improvement was noted with five cycles of plasmapheresis and injection of rituximab. Psychiatric manifestations are common, and child and adolescent psychiatrists are frequently the first to be contacted for patients with anti-NMDAR encephalitis. There is, therefore, an increasing need for them to become aware of the disorder and consider it in their differential diagnosis. A better prognosis can be achieved with appropriate evaluation by a multi-disciplinary team.