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

Abstract

Background: Diagnosis of internal external ventricular drain (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 were collected from 21 neurosurgical units in the United Kingdom from 2014 to 2015. Confirmed iERI was defined as clinical suspicion of infection with positive cerebrospinal fluid (CSF) culture and/or Gram stain. Cerebrospinal fluid, blood, and clinical parameters and antimicrobial management were compared between the 2 groups. Mortality and Modified Rankin Scores were compared at 30 days post-EVD insertion.

Results: Internal EVD-related infection was suspected after 46 of 495 EVD insertions (9.3%), more common after an emergency insertion. Twenty-six of 46 were confirmed iERIs, mostly due to Staphylococci (16 of 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, although 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 (10 days [interquartile range {IQR}, 7-24.5] for confirmed cases and 9.5 days [IQR, 5.75-14] for suspected, P = 0.3). Despite comparable baseline characteristics, suspected iERI was associated with lower mortality and better neurological outcomes.

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.

Keywords: antimicrobial treatment; aseptic meningitis; external ventricular drain; intraventricular antimicrobials; post-neurosurgical meningitis.

Figure 1.

Study cohort overview. *, Two organisms found in culture, matching morphology for 1 organism on Gram stain. EVD, external ventricular drain; ERI, EVD-related infection;

Figure 2.

Cerebrospinal fluid (CSF), blood, and clinical parameters. The CSF glucose results were recorded for 11 cases of suspected internal external ventricular drain-related infection (iERI) and 14 cases of confirmed iERI. Data points represent patients. Bars on dot plots show median and interquartile range. A: CSF parameters; B: Peripheral blood parameters; C: Clinical features. *, P < .05, ns: not significant.

Figure 3.

Flowchart of antimicrobials received.