Immunotherapy for anti-NMDAR encephalitis: A review of paraneoplastic, autoimmune encephalopathy

Paraneoplastic immune-mediated encephalopathy is a recently described disease. Dalmau et al first linked the presence of Anti-N-methyl-d-aspartate receptor (anti-NMDAR) antibodies to paraneoplastic psychiatric and neurologic disease after encountering a case of anti-NMDAR encephalitis in a woman with ovarian teratoma in 2007. Nerve cells from a teratoma or previous viral infection could trigger autoantibodies, causing NMDA receptors to become dysfunctional in neurotransmission across synapses. Symptoms of anti-NMDAR encephalitis include prodromal symptoms, psychiatric symptoms, speech dysfunction, seizure, abnormal neurological movement, and autonomic dysfunction. This disease is reversible and treatable; however, early diagnosis and treatment are essential as they may prevent excess antibodies from causing severe or prolonged harm in the brain. First-line Immunotherapy includes intravenous high-dose steroids (methylprednisolone), intravenous immunoglobulin (IVIG), and/or plasmapheresis. Second-line immunotherapy includes targeted B-cell therapy with rituximab and cyclophosphamide. Taiwan is one of the countries where tests for detecting this disease, which are expensive, are not currently available. A cell-based indirect immunofluorescence test for the detection of IgG antibodies against the NMDA receptor should become more available for aiding diagnostics. Most importantly, early immune modulatory therapy including steroid, IVIG, and plasma exchange should become financially more feasible for use in treatment in Taiwan.