[Prognostic value of VZV PCR in cerebrospinal fluid in neurological manifestations of varicella].

Varicella-zoster virus (VZV) is, like other alphaherpes viruses, neurotropic. Of the admissions to hospital for varicella, 7.6-25% are due to neurologic manifestations. Most of the time, the concomitant skin lesions facilitate the diagnosis. The justification of qualitative PCR (polymerase chain reaction) for VZV DNA in cerebrospinal fluid in the management of these patients is not clear. The aim of this study was to evaluate the prognostic value of qualitative PCR for VZV DNA in cerebrospinal fluid and to assess its impact on patient management. We conducted a retrospective monocentric study in Versailles Hospital (France). It included every child admitted for neurologic manifestations associated with varicella and compared the patients with positive PCR for VZV DNA to those with a negative PCR in the cerebrospinal fluid. Seven patients with positive PCR and 16 patients with negative PCR were included. The median age of the children included was 3 years (range, 1.6-12 years) and 2 years (range, 0.6-5 years), respectively. In the positive PCR group, 86% of the children had fever on first examination and the average time between the onset of skin lesions and neurological signs was +1.28 days (range, -2 to +5 days). In comparison, in the negative PCR group, 81% of the children had fever and the average time delay was +1.75 days (-2 to +7 days). There was no significant difference in terms of length of hospitalization; 3 days (range, 0-6 days) and 3 days (range, 2-7 days), respectively. All patients discharged from our department went home. In addition, there was no significant difference between the two groups in terms of treatment with acyclovir; two children (28.5%) were treated in the positive PCR group versus four (25%) in the negative PCR group. Our study showed no prognostic value for qualitative PCR for VZV DNA in the cerebrospinal fluid of patients with neurologic manifestations of varicella. Therefore, its relevance can be questioned in clinical practice. However, in case of encephalitis and meningitis during primary infection with VZV, quantitative PCR for VZV DNA might have a prognostic value and therefore requires further study.