Comparison of Suspected and Confirmed Internal External Ventricular Drain-Related Infections: A Prospective Multicenter United Kingdom Observational Study

Abstract

Background Diagnosis of internal EVD-related infections (iERI) is an area of diagnostic difficulty. Empiric treatment is often initiated on clinical suspicion. There is limited guidance around antimicrobial management of confirmed versus suspected iERI. Methods Data on patients requiring EVD insertion was collected from 21 U.K. neurosurgical units from 2014-2015. Confirmed iERI was defined as clinical suspicion of infection with positive cerebrospinal fluid (CSF) culture and/or Gram stain. CSF, blood, and clinical parameters, and antimicrobial management were compared between the two groups. Mortality and Modified Rankin Scores were compared at 30 days post-EVD insertion. Results iERI was suspected following 46/495 EVD insertions (9.3%), more common after an emergency insertion. 26/46 were confirmed iERIs, mostly due to Staphylococci (16/26). When confirmed and suspected infections were compared, there were no differences in CSF white cell counts or glucose concentrations, nor peripheral blood white cell counts or C-reactive protein concentrations. The incidence of fever, meningism and seizures was also similar though altered consciousness was more common in people with confirmed iERI. Broad-spectrum antimicrobial usage was prevalent in both groups with no difference in median duration of therapy (10d [IQR7-24.5] for confirmed cases and 9.5d [5.75-14] for suspected, p = 0.3). Despite comparable baseline characteristics, suspected iERI was associated with lower mortality and better neurological outcomes, suggestive of either. Conclusions Suspected iERI could represent sterile inflammation or lower bacterial load leading to false-negative cultures. There is a need for improved microbiology diagnostics and biomarkers of bacterial infection to permit accurate discrimination and improve antimicrobial stewardship.