Management of psychiatric symptoms in anti-NMDAR encephalitis: a case series, literature review and future directions

Anti-NMDA receptor (NMDAR) encephalitis, formally recognized in 2007, has been increasingly identified as a significant cause of autoimmune and paraneoplastic encephalitis. Approximately 80% of the patients are females. The characteristic syndrome evolves in several stages, with approximately 70% of the patients presenting with a prodromal phase of fever, malaise, headache, upper respiratory tract symptoms, nausea, vomiting and diarrhoea. Next, typically within two weeks, patients develop psychiatric symptoms including insomnia, delusions, hyperreligiosity, paranoia, hallucinations, apathy and depression. Catatonic symptoms, seizures, abnormal movements, autonomic instability, memory deficits may also develop during the course of the disease. Presence of antibodies against the GluN1 subunit of the NMDAR in the CSF and serum confirm the diagnosis of NMDAR encephalitis, which also should prompt a thorough search for an underlying tumor. Age, gender, and ethnicity may all play a role, as black females older than 18 years of age have an increased likelihood of an underlying tumor. Treatment is focused on tumor resection and first-line immunotherapy [corticosteroids, plasma exchange, and intravenous immunoglobulin]. In non-responders, second- line immunotherapy [rituximab or cyclophosphamide or combined] is required. More than 75% of the patients recover completely or have mild sequelae, while the remaining patients end up demonstrating persistent severe disability or death. There is a paucity of literature on the management of psychiatric symptoms in this population. Given the neuropsychiatric symptoms in the relatively early phase of the illness, approximately 77 % of the patients are first evaluated by a psychiatrist. Earlier recognition of this illness is of paramount importance as prompt diagnosis and treatment can potentially improve prognosis. We describe two patients diagnosed with NMDAR encephalitis presenting with two different psychiatric manifestations. The first patient presented with psychotic mania and catatonic symptoms, while the second suffered from depression with psychotic and catatonic features refractory to psychotropic medications. We review of the use of psychotropic medications and ECT to address insomnia, agitation, psychosis, mood dysregulation and catatonia in NMDAR encephalitis.