RESPONSE OF ANTI-NMDA RECEPTOR ENCEPHALITIS WITHOUT TUMOR TO IMMUNOTHERAPY INCLUDING RITUXIMAB

Abstract

Paraneoplastic encephalitis with antibodies against NR1/NR2 heteromers of the NMDA receptor associates frequently with ovarian teratoma and has recently been established as a distinct clinical entity.1 Most patients are young women who develop a syndrome with prodromal cold-like illness, intractable seizures, psychosis, dyskinesia, and hypoventilation.1,2 However, about 40% of patients do not have a detectable tumor,3 and the treatment of these patients remains unclear. We report a patient with anti-NR1/NR2 encephalitis without teratoma who showed a nearly complete recovery after intensive immunotherapy including rituximab. ### Case report. A 42-year-old woman had cough and headache for 3 weeks. On the day before admission, she was found to be unresponsive for several minutes, and subsequently developed generalized seizures. On admission, her temperature was 38.2°C, and she had meningeal signs. CSF revealed mild pleocytosis (10/mm3) and slightly elevated protein concentration (45 mg/dL) with normal glucose concentration and IgG index. MRI (figure, A) and EEG were unremarkable. After the seizures were controlled, minimal disorientation was observed. Acyclovir and ceftriaxone were started. Figure MRI and FDG-PET studies of the brain (A) On day 2, the FLAIR MRI was normal. (B) On day 18, the FLAIR image revealed new high-intensity areas in the right temporal cortex, insula, parts of the frontal, parietal, and occipital cortices, and hippocampus. These findings were accompanied by mild edema. High-intensity areas were also observed in the left inferior temporal cortex and hippocampus. (C) On day 18, the gadolinium-enhanced T1-weighted …