Lack of value of routine analysis of cerebrospinal fluid for prediction and diagnosis of external drainage–related bacterial meningitis

Abstract

Object. Routine microbiological and chemical analysis of cerebrospinal fluid (CSF) is often performed to diagnose external drainage-related bacterial meningitis (ED-BM) at an early stage. A cohort study was performed to investigate the value of several commonly used CSF parameters for the prediction and diagnosis of ED-BM.Methods. In a cohort of 230 consecutive patients in whom external drains had been placed, CSF samples were collected daily, prospectively evaluated for the presence of bacteria using Gram stain and microbiological culture, and analyzed for leukocyte count, protein concentration, glucose concentration, and ratio of CSF glucose to blood glucose. In addition, the CSF concentration of interleukin-6 (IL-6) was determined. The definition of ED-BM was based on positive culture results in combination with clinical symptoms. A matched case-control study was performed to evaluate the cohort longitudinally and to control for biasing factors such as duration of external drainage. External drainage-related bacterial meningitis developed in 22 patients (9.6%). Results from analyses of 1516 CSF samples showed no significant differences between the patients in whom ED-BM developed and a control group without ED-BM during the first 3 days of infection or during the 3 days preceding the infection with regard to leukocyte count, protein concentration, glucose concentration, and CSF/blood glucose ratio. No significant difference between groups was found for the CSF IL-6 concentration during the 3 days preceding the infection. In the matched case-control study, none of the parameters had significant predictive or diagnostic value for ED-BM in analyses using absolute values, ratios, and differences between the current and previous day's values. A comparison of the results from Gram stains and CSF cultures showed that the Gram staining had a very high specificity (99.9%) but a low sensitivity (18% [four of 22 patients] on the 1st day of infection and 60% [nine of 15 patients] on the 2nd day).Conclusions. Severe disturbances in the CSF of patients with external drains limit the value of routine CSF analysis for prediction or diagnosis of ED-BM. Routine Gram stain of CSF has also limited predictive or diagnostic value due to its low sensitivity in screening for ED-BM. KEY WORDS • bacterial meningitis • cerebrospinal fluid drainage • central nervous system infection E 101Abbreviations used in this paper: CSF = cerebrospinal fluid; ED-BM = external drainage-related bacterial meningitis; IL = interleukin; ROC = receiver operating characteristic.

Does release of antimicrobial agents from impregnated external ventricular drainage catheters affect the diagnosis of ventriculitis?

“…This would give different results from those used in our paper, which we consider to be more relevant to EVD catheter conditions in use. Their study covered only the first 24 hours, but samples of CSF for diagnosis are unlikely to be obtained so early after placement of the catheter, and practice varies: some obtain samples at 3 or 5 days, some 3 times weekly, and some only if clinically indicated, [5][6][7]14 and clinical concern regarding infection usually does not arise so soon as within 24 hours after placement. 8,9,15 The detection method of Stevens et al for drug release (capillary electrophoresis) did not allow quantitative determination of actual drug levels in the saline, whereas our methods (HPLC and LC-MS) were able to accurately determine the concentrations of drugs in the perfusates at each time point.…”

2017 Infectious Diseases Society of America’s Clinical Practice Guidelines for Healthcare-Associated Ventriculitis and Meningitis*

“…Note that CSF may not need to be obtained if another clear source of infection has been identified. Changes in CSF parameters may be subtle [14], thus making it hard to determine if the abnormalities are related to infection or secondary to the underlying reason for catheter placement or a result of neurosurgery [55,56]. Although high CSF white blood cell counts correlate with the presence of infection, infection may be present even in patients with normal CSF white blood cell counts.…”

“…All 7 patients with infection had fever (>38.5°C) and peripheral leukocytosis (>11 000/mm 3 ) on the day the infection was identified, and 1 had a change in CSF appearance. A prospective study also demonstrated no value of routine analysis of CSF for prediction and diagnosis of external drain-related bacterial meningitis [56]. Another study assessed whether the incidence of ventriculitis changed when CSF sampling frequency was reduced to once every 3 days [152].…”

“…Conversely, it should also be considered that in many patients with CSF shunts in the ventricular space, the lumbar cistern may not be in communication with the ventricular space, as is the case in obstructive hydrocephalus. In one cohort study of 230 consecutive patients with external CSF drains [56], CSF samples were collected daily and prospectively evaluated for the presence of bacteria using Gram stain and culture. In this study, lumbar catheters were placed in 125 patients (54.3%), ventricular catheters in 97 patients (42.2%), and more than 1 type of catheter in 8 patients (3.5%).…”

Fevers and abnormal blood and cerebrospinal fluid studies after pediatric cerebral hemispherectomy: impact of etiology and age at surgery

“…These findings indicate that elevated temperatures and abnormal blood and CSF studies are poor predictors of CNS infections after large cranial procedures, especially in children. 12,14 It should be recognized that our clinicolaboratory associations could be related to other variables strongly linked with etiology, such as perioperative blood loss and intravenous fluid management, as previously reported. 3 Why some seizure etiologies are associated with differential changes in blood and CSF studies rather than other etiologies is unclear and not a component of the present study design.…”