Anti-N-methyl-d-aspartate receptor encephalitis in a patient on long-term continuous immunomodulatory therapy

Background

Anti-N-methyl-d-aspartate [anti-NMDA] receptor encephalitis is one of the most common types of immune-mediated encephalitis. It is characterized by a neuropsychiatric syndrome associated with immunoglobulin G [IgG]-type antibodies against the NMDA receptor's GluN1 subunit in cerebrospinal fluid [CSF]. To our Knowledge, only six cases of autoimmune encephalitis with positive CSF NMDA receptor IgG autoantibodies have been reported among patients on long-term immunosuppressive therapies. The etiologies of all six cases were related to solid organ transplantation. Therefore, this report is the first to present a case of immunosuppression associated with an etiology other than post-transplant immunosuppression.

Case presentation

We present the case of a 59-year-old female patient who was on a long-term continuous immunomodulatory therapy for rheumatoid arthritis, and she consulted the emergency department several times for headache, symptoms of neurologic deficit, and subsequent progression to neuropsychiatric symptoms. CSF examination of the patient confirmed the presence of antibodies against the NMDA receptor; hence, the diagnosis of anti-NMDA receptor encephalitis was made.

Conclusions

It is important to recognize the clinical features of autoimmune encephalitis and to consider this condition in the differential diagnosis when neuropsychiatric symptoms are manifested in such patients. Patients on long-term immunomodulatory therapy present with atypical manifestations of anti-NMDA receptor encephalitis. The consideration of these manifestations in the differential diagnosis can ensure efficient diagnosis, management, and reduction in the consequences affecting morbidity and mortality of these patients.