Acute varicella zoster virus encephalitis in adults - relationship between viral load, time, clinical features and outcome
7 slide(s) – English – 2011-09-10
Background. To determine how the viral load of varicella zoster virus (VZV) in the cerebrospinal fluid (CSF) of patients with encephalitis varies with time and whether this predicts outcome.
Methods. The Liverpool virology laboratory electronic records were screened for patients with VZV polymerase chain reaction (PCR) positive CSF over 5 years. Viral load was determined by quantitative PCR. A poor outcome was defined as moderate disability to death (Glasgow outcome score [GOS] 2-5) and a high viral load as (>5x104 copies/μl of CSF).
Results. Of 608 patients screened; 36 had VZV PCR; 12 were positive and had encephalitis. In this, the first study to assess the temporal relationship, we identified a strong negative correlation between time to LP and viral load (tau b= -0.59, p=0.036). There was no significant correlation between viral load and outcome overall (tau b= 0.35, p=0.26). However, all three patients with a high viral load had a poor outcome and four of six patients with a low viral load had a good outcome (p=0.14).
Conclusions. CSF viral load appears to more closely relate to time of LP from symptom onset than to outcome. Timing of LP should be taken into account in future studies.