Accuracy of clinical presentation for differentiating bacterial from viral meningitis in adults: a multivariate approach.

OBJECTIVE: To determine whether bacterial (BM) and viral (VM) meningitis can be differentiated based on initial clinical presentation. DESIGN AND SETTING: Retrospective cohort study in a medical emergency department and intensive care unit in a university hospital. PATIENTS: 144 adults, including 90 with confirmed BM and 54 unpretreated VM. MEASUREMENTS AND RESULTS: Symptoms, examination findings, paraclinical data, and clinical outcome were assessed. Severity was defined by the presence at referral of one of the following criteria: altered consciousness, seizures, focal neurological findings, and shock. After univariate analyses we performed stepwise logistic regression to determine predictors for BM available at referral (except for CSF Gram stain) and logistic regression using previously validated CSF cutoffs. Univariate methods identified the presence of one sign of severity as the most important predictor for BM (sensitivity 0.989, specificity 0.981, positive predictive value 0.989, negative predictive value 0.981, odds ratio 4,770) and showed that CSF results differ in BM and in VM (except for CSF glucose). Logistic regression analysis revealed severity and CSF absolute neutrophil count as the two predictors of BM (R2=0.876). Logistic analysis showed that BM was related to severity (beta=6.46+/-1.27) and a CSF absolute neutrophil count above 1,000/mm3 whereas CSF glucose below 2 mmol/l and CSF protein higher than 2 g/l were not predictive. CONCLUSIONS: The presence of at least one sign of severity at referral and a CSF absolute neutrophil count above 1,000/mm3 mm are predictive of BM.

Increased diffusion of soluble adhesion molecules in meningitis, severe sepsis and systemic inflammatory response without neurological infection is associated with intrathecal shedding in cases of meningitis.

OBJECTIVE: Sepsis and systemic inflammatory response syndrome (SIRS) result in the release in plasma of inflammatory cytokines and soluble forms of adhesion molecules in relation to endothelial activation. This study was designed to compare cerebrospinal fluid (CSF) concentrations of adhesion molecules in meningitis and SIRS without neurological infection and to evaluate in meningitis whether they originate from passive diffusion through damaged blood-CSF barrier or from local production. DESIGN: Prospective observational study. SETTING: University hospital medical intensive care unit. PATIENTS: Nineteen patients with meningitis and 41 patients with sepsis or SIRS without cerebrospinal infection consecutively admitted to the critical care unit over an 18-month period. INTERVENTIONS: Soluble forms of adhesion molecules (ICAM-1, VCAM-1, E-selectin) and cytokines (interleukin (IL)-1beta and TNF-alpha) were measured in paired CSF and blood samples. RESULTS: Serum concentrations of soluble adhesion molecules and cytokines were increased in the two groups, without significant differences. The CSF concentrations were elevated in both cases, whereas patients with meningitis demonstrated significantly higher CSF concentrations of soluble ICAM-1, VCAM-1, E-selectin, and TNF-alpha ( p<0.001), with higher corresponding CSF/serum ratios. Correlations between CSF and serum concentrations were found only in meningitis. These correlations were strong for soluble ICAM-1 (r(2)=0.7, p<0.001) and E-selectin (r(2)=0.9, p<0.001), but weaker for VCAM-1. VCAM-1 CSF/serum ratios were increased, in comparison with ICAM-1 and E-selectin CSF/serum ratios, despite similar molecular weights. Serum and CSF levels of cytokines and adhesion molecules were not predictive of death for the whole population, except concentrations of ICAM-1 significantly increased in non-surviving patients ( p<0.05). CONCLUSIONS: The CSF soluble adhesion molecules are increased in sepsis, SIRS and meningitis. In meningitis, the correlation between CSF and serum concentrations of adhesion molecules and the presence of a discrepancy of CSF/serum ratios for molecules of the same molecular weight may suggest intrathecal shedding in addition to diffusion through blood-CSF barrier.