Anti-NMDAR encephalopathy: Treatment

Anti-NMDAR encephalopathy is included in paraneoplastic limbic encephalopathy and show the good response to treatment compared to other paraneoplastic syndromes. Treatment of anti-NMDAR encephalopathy includes immunotherapy and/or tumor removal. About 65% of patients with anti-NMDAR encephalopathy had fully or near-full recovery. Immunotherapy is principally necessary and effective in patients with and without tumor. Corticosteroids and intravenous immunoglobulin are most frequently used. It is likely that patients who do not respond to one form of immunotherapy might respond to others regimens including plasmapheresis, cyclophosphamide, and rituximab. A tumor was found in 58% of patients with anti-NMDAR encephalopathy. Early removal of tumor should be considered based on following reasons. First, patients with ovarian teratoma showed higher mortality and higher titer of anti-NMDAR antibody compared with those without. Second, relapsing neurological symptoms occurred in 13% of patients, usually related to a delay in tumor diagnosis. Third, when a tumor was found and removed, recovery was faster and predictable. However, early removal of tumor cannot be conducted because of unstable conditions such as hypoventilation and dyskinesias. In supportive cares, severe central hypoventilation requires mechanical ventilation. The involuntary movements and facial dyskinesias are refractory to anti-epileptic drugs. In conclusion, search for and removal of an ovarian teratoma should be promptly considered after the diagnosis of anti-NMDAR encephalopathy.