Comparison of suspected and confirmed internal EVD-related infections: a prospective multi-centre U.K. observational study

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.

Abstract WP15: Role Of Grade Among Glioma Patients And Risk Of Cerebrovascular Mortality: A Population-based Analysis

Introduction: Glioma is the most common malignant type of brain tumours. Glioma patients are at higher risk for cerebrovascular mortality compared to the general population and other cancer types. Whether the risk differs by the grade, a marker of aggressiveness in gliomas, remains unclear.

Methods: Using the US National Cancer Institute’s Surveillance Epidemiology and End Results program, we identified adult patients with a primary diagnosis of malignant gliomas in 2000 to 2018 (N=72,252). Age-, sex-, and calendar-year- adjusted standardized mortality ratios (SMRs) were calculated for cerebrovascular mortality comparing glioma patients with the general population. Gliomas were classified into four grades based on WHO definition in which increasing grade indicates the higher degrees of invasiveness. Hazard ratio (HR) and 95% confidence interval (CI) were calculated using Cox regression model to examine cerebrovascular mortality in patients with different grades of gliomas.

Results: Over 80% of patients were diagnosed with high grade gliomas (Grade 3 & 4). Patients with gliomas in all grades had excess cerebrovascular mortality compared with the general population (SMRs 2.64-4.18, p<0.001). Younger patients (< 50 years) with glioblastoma (Grade 4), the most aggressive type, had substantially greater risk (SMR 12.73, p<0.001) than the general population compared to those with lower grades (SMR 7.14 & 6.31 in Grade 2 & 3, p<0.001). In grade 4, Hispanic patients had highest risk (SMR 6.23, p<0.001) than other ethnic groups (SMR 3.67 & 4.92 in White and Black respectively, p<0.001). In case-only analysis, patients with Grade 4 were significantly associated with increased cerebrovascular mortality compared to the lower grade (HR=1.41, 95% CI 1.01-1.97, p<0.01) after adjustment of socio-demographic and treatment (surgery, radiation and chemotherapy) characteristics.

Conclusions: The findings of higher grades of gliomas associated with cerebrovascular mortality support further research to understand the role of aggressiveness and other risk factors in brain cancer-associated fatal stroke.