High-dose diazepam controls severe dyskinesia in Anti-NMDA receptor encephalitis

Objective Since there is no standard treatment to control dyskinesia in anti-NMDA receptor (NMDAR) encephalitis, we analyzed therapeutic efficacy of high-dose diazepam in dyskinesia associated with NMDAR encephalitis.

Methods We reviewed NMDAR encephalitis patients with dyskinesia, who were admitted to Seoul National University Hospital between November 2012 and July 2018. High-dose diazepam was administered orally or via a nasogastric tube, 3–6 times a day. We assessed the treatment effect by comparing dyskinesia severity on the first day when the diazepam treatment reached the highest dose, with after 1 week of highest dose of diazepam treatment.

Results Among 68 NMDAR encephalitis patients during study period, 33 patients were treated with enteral diazepam (ranging from 6 mg to 180 mg) to control dyskinesia, along with immunotherapy. The severity of dyskinesia improved from average grade 2.4 ± 0.6 to 1.1 ± 0.7, after 1 week of the highest dose of diazepam (mean severity change −1.4 ± 0.6, 95% confidence interval −1.2 to −1.6; p < 0.001). No patients had serious adverse events except mild sedation.

Conclusions Dyskinesia in NMDAR encephalitis improved after treatment with enteral diazepam without significant side effects. This study suggests enteral diazepam could be a treatment option for control dyskinesia in NMDAR encephalitis.

Classification of evidence This study provides Class IV evidence that for patients with dyskinesias associated with NMDAR encephalitis, enteral diazepam is effective and safe in dyskinesia control.