Acute manic state with psychotic features in a teenager with autoimmune encephalitis: a case report

Autoimmune disorders have become increasingly acknowledged as having a more causative role in encephalitis than previously assumed. Anti-N-methyl-D-aspartate receptor encephalitis seems to be the most prevalent disorder. Symptoms of the neuropsychiatric phase in children and adolescents include abnormal behavior, seizures, and neurologic symptoms. We present a report on a teenage girl with predominantly psychiatric symptoms, highlighting the need for awareness of the disease and multidisciplinary collaboration.

Our patient, a 17-year-old girl of Middle Eastern origin, had no earlier medical history, but a family history of autoimmune disease. One morning, she could not recognize her mother and soon developed increased energy and pressured speech. The condition worsened, with paranoid delusions. In the emergency unit, she ran around speaking incoherently. The condition was interpreted as a full-scale mania. After pediatric clearance, the patient was admitted to the Department of Child and Adolescent Psychiatry. Mood-stabilizing treatment was initiated with second-generation psychotics and lithium, but this brought no improvement. A multidisciplinary discussion was held with physicians from psychiatry and neurology. A lumbar puncture showed N-methyl-D-aspartate receptor antibodies, and autoimmune treatment was initiated. Computed tomography thorax/abdomen revealed a right-sided ovarian tumor. After salpingo-oophorectomy, our patient's mental status gradually improved, as demonstrated by repeated testing. Seven months post discharge she was in a stable relationship and performing well in school.

This case underlines the importance of collaboration between child and adolescent psychiatry and pediatrics, and gives pointers for timely diagnosis. Manic adolescents who do not respond to mood-stabilizing treatment should be subjected to further consultations and investigations. Psychiatrists and neurologists should develop an integrated approach to the management of brain disorders.