Herpes simplex virus‐induced anti‐N‐methyl‐d‐aspartate receptor encephalitis: a systematic literature review with analysis of 43 cases

Aim To conduct a systematic literature review on patients with biphasic disease with herpes simplex virus (HSV) encephalitis followed by anti‐N‐methyl‐D‐aspartate receptor (NMDAR) encephalitis. Method We conducted a case report and systematic literature review (up to 10 December 2016), focused on differences between herpes simplex encephalitis (HSE) and anti‐NMDAR encephalitis phases, age‐related characteristics of HSV‐induced anti‐NMDAR encephalitis, and therapy. For statistical analyses, McNemar's test, Fisher's test, and Wilcoxon rank sum test were used (two‐tailed significance level set at 5%). Results Forty‐three patients with biphasic disease were identified (31 children). Latency between HSE and anti‐NMDAR encephalitis was significantly shorter in children than adults (median 24 vs 40.5d; p=0.006). Compared with HSE, anti‐NMDAR encephalitis was characterized by significantly higher frequency of movement disorder (2.5% vs 75% respectively; p