Clinical characteristics and treatment of varicella zoster virus central nervous system infection in an Australian tertiary hospital.

Background and aim: Varicella zoster virus (VZV) is a neurotropic herpesvirus. With improved access to molecular diagnostics, there is increasing recognition of VZV with central nervous system involvement. This study aimed to describe the demographic, clinical and treatment characteristics of patients admitted to an Australian tertiary hospital with VZV central nervous system infection.

Methods: Retrospective study of all adult patients (aged ≥18 years) presenting to an Australian tertiary hospital between November 2010 and May 2023 with a clinical syndrome of or imaging consistent with meningitis or encephalitis and detectable VZV DNA in cerebrospinal fluid using polymerase chain reaction.

Results: There were 48 cases of VZV meningitis and 13 cases of VZV encephalitis identified during the study period. The median age of patients with VZV meningitis and encephalitis was 34 years (range 21-86 years) and 73 years (range 22-94 years) respectively. All patients with VZV encephalitis and 37 of 48 (77.1%) with meningitis received intravenous (IV) acyclovir. Eight patients with VZV meningitis were treated with oral antivirals alone and seven were managed without antivirals or with ≤48 h of empiric antiviral therapy only; none of these patients experienced an adverse clinical outcome. Two patients with VZV encephalitis died. Seven patients experienced neurological complications, three with VZV meningitis and four with VZV encephalitis. Age and length of stay were associated with adverse clinical outcomes.

Conclusion: VZV encephalitis predominates in older patients while VZV meningitis predominates in younger patients. IV acyclovir remains the standard of care for treatment of VZV encephalitis; however, its role in VZV meningitis is less clear. Controlled trials should be conducted to inform its use, particularly in low-risk patients with VZV meningitis.