Herpes simplex viruses (1 and 2) and varicella-zoster virus infections in an adult population with aseptic meningitis or encephalitis: A nine-year retrospective clinical study

Three α-herpesviruses are known to be associated with central nervous system (CNS) infection; however, there are limited data on the incidence and clinical characteristics of α-herpesviruses CNS infections. This study aimed to assess the clinical manifestations, laboratory findings, and outcomes in patients with human herpes simplex virus 1 (HSV-1), human herpes simplex virus 2 (HSV-2), and varicella-zoster virus (VZV) CNS infections. We identified cases of HSV-1, HSV-2, and VZV CNS infections and reviewed their clinical and laboratory characteristics. The study population was drawn from patients with HSV-1, HSV-2, and VZV polymerase chain reaction positivity in cerebrospinal fluid (CSF) who visited Pusan National University Hospital between 2010 and 2018. During the 9-year study period, a total of 727 CSF samples were examined, with 72.2% (525/727) patients identified as having a CNS infection. Of 471 patients with aseptic meningitis and encephalitis, the causative virus was identified in 145 patients, and no virus was detected in 337 patients. A total of 15.2% (80/525) were diagnosed with one of the 3 herpesviruses as causative agents, 59 patients had meningitis, and 21 patients had encephalitis. Eleven patients with HSV-1, 27 patients with HSV-2, and 42 patients with VZV CNS infections were included. The distribution of cases by age showed different patterns depending on the type of herpesvirus infection. Compared with the HSV-1 group, the median age in the HSV-2 group was younger (HSV-1: 58 years; HSV-2: 38 years; P = .004), and patients with VZV infections showed a bimodal age distribution. Encephalitis was more common in the HSV-1 group, and HSV-1 infection was associated with a poor prognosis at discharge. CSF white blood cell counts were significantly lower in patients infected with HSV-1 (117 × 10(6) cells/L) than in patients infected with VZV (301 × 10(6) cells/L) (P = .008). These 3 herpesviruses are important causes of CNS infections regardless of immunologic status. HSV-1 infection was commonly associated with encephalitis and poor prognosis; HSV-2 and VZV CNS infections were associated with a low risk of mortality and neurological sequelae.