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.

P11.07.B What is the role of brain biopsy in the diagnosis of brain lesions?

Background

Brain biopsies have a role in establishing histological diagnoses for intrinsic tumours not amenable to surgical resection or lesions with an uncertain radiological diagnosis. Despite their utility, they are associated with several risks, particularly surgical complications and non-diagnostic samples. On this background, this study sought to determine the diagnostic yield and outcomes of brain biopsies carried out in a tertiary centre and explore factors which could influence the overall success of such procedures.

Material and Methods

All non-endoscopic brain biopsy procedures performed over a 1-year period (01/04/2020 to 01/04/2021) at one of the largest neurosurgical units in the UK were included. Hospital electronic records were used to identify eligible patients and determine relevant patient, procedure and outcome data. Mortality data were obtained with a minimum follow-up period of 1 year.

Results

A total of 75 cases were identified, including 55 burr hole biopsies and 20 open procedures. Overall, 16 (21%) biopsies were non-diagnostic, including 25% of burr hole biopsies and 10% of open biopsies. Procedures performed by a consultant had a lower non-diagnostic rate (17%) than cases with no consultant involvement (27%). Suspected inflammatory conditions had a higher non-diagnostic rate (55%) than suspected tumours (11%). Excluding non-diagnostic cases, histological diagnosis was in line with suspected pre-operative diagnosis in 70% of cases. Post-operative complications included 3 symptomatic haematomas and 1 subdural empyema, which led to one post-operative death. A total of 40 (55%) patients died within the follow-up period, including 10 (13%) within 60 days of their procedure. Six-month and 1 year survival rates were 35% and 26% for glioblastoma, respectively, and 70% and 70% for lymphoma. The majority (68%) of patients with a performance status (PS) of 3 or 4 prior to surgery died within 1 year, as compared to 42% with a PS of 0-2.

Conclusion

Brain biopsies are an important adjunct to managing CNS lesions due to the limitations of a radiological diagnosis alone. The diagnostic yield was greater for suspected neoplastic lesions, in cases with consultant involvement, and with open procedures.