1 Department of Pediatrics, University of Tsukuba Hospital, Ibaraki, Japan, AND Department of Emergency and Critical Care Medicine, University of Tsukuba Hospital, Ibaraki, Japan.

2 Department of Child Health, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.

3 National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, NHO, Shizuoka, Japan.


Anti-N-methyl- d-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune neurological disorder that usually occurs as a paraneoplastic syndrome and is particularly associated with ovarian teratoma. Standard therapy for severe cases is not established and the prognosis in patients who do not respond to first-line treatment is poor.
Case Report
An 11-year-old boy complained psychiatric symptoms and rapidly lost consciousness. CT scan revealed mediastinal teratoma and serum/spinal fluid was positive for anti-NMDAR antibody. He kept comatose and his brain stem function was profoundly disturbed. His symptoms were refractory to first-line therapy, which involved tumor resection, methylprednisolone (mPSL) pulse, Intravenous immunoglobulin (IVIG), and plasma exchange. We administered a combination therapy of rituximab and cyclophosphamide as second-line therapy and achieved complete recovery without adverse effects related to treatment.
 We consider early intensive treatment with a combination of rituximab and cyclophosphamide to be a safe and effective option for severe cases of anti-NMDAR encephalitis.