Atypical anti-NMDA receptor encephalitis associated with varicella zoster virus infection

The triggering effect of herpes simplex virus infection on the development of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is now well established. However, there are very few reports that has linked a varicella zoster virus (VZV) reactivation with anti-NMDAR encephalitis. In this report, we describe a case of a 57-year-old man presented with atypical clinical presentation of anti-NMDAR encephalitis with gait ataxia, complete ophtalmoplegia, and abolished reflexes followed by drowsiness and confusion. Initial diagnosis of Bickerstaff's brainstem encephalitis was suspected. Few days later, the patient developed herpes zoster in a localized right T1-T2 dermatome. Cerebrospinal fluid (CSF) polymerase chain reaction (PCR) for VZV was negative. CSF anti-NMDA antibodies were proved positive. A diagnosis of anti-NMDAR encephalitis with concomitant VZV skin reactivation was retained. Favorable outcome with combined antiviral treatment and immunomodulatory therapy was observed. Concomitant VZV reactivation with autoimmune encephalitis is possible. Prognosis and therapeutic options in this rare condition remain to be clarified.