Infection of the central nervous system caused by varicella zoster virus reactivation: a retrospective case series study.

Background: Recent data suggest that varicella zoster virus (VZV)-associated complications of the central nervous system (CNS) are more common and diverse than previously thought. The main purpose of this article is to describe the clinical characteristics and the outcome of patients suffering from meningitis and encephalitis caused by VZV reactivation.

Methods: A retrospective case study of adult patients (≥16 years old) diagnosed with a VZV reactivation in the CNS was performed. The cases were identified by a qualitative PCR DNA assay of the cerebrospinal fluid (CSF) at the Regional Hospital of Lugano between January 1, 2003 and July 31, 2010.

Results: Eleven out of 519 CSF samples (2.1%), submitted from patients with a clinical diagnosis of viral meningitis or encephalitis, were positive for VZV. A vesiculo-pustular skin eruption was observed in only five patients (45%). In six cases (55%), a systemic inflammatory syndrome was absent. The clinical outcome was favorable in eight patients (73%). Only one out of 11 patients (9%) died. The four patients with encephalitis had a less favorable prognosis: one patient recovered without residual neurological sequelae; two had a chronic neuropsychological handicap, speech difficulties, facial nerve palsy, and focal seizures; one patient died. We estimated an annual incidence rate of VZV infection of the CNS of 1.02/100,000 inhabitants for southern Switzerland.

Conclusions: Screening of CSF for VZV by PCR is recommended for all patients with encephalitis and for those with viral meningitis of unclear origin in order to better target antiviral treatment.