Predictive factors of bacterial meningitis in the patients seen in emergency departments.

Objetives: To analyse and compare predictive factors of bacterial meningitis in the patients seen in the Emergency Departments (ED) due to an episode of acute meningitis (AM).

Methods: A prospective, observational study was carried out in patients aged 15 years and older seen in ED due to AM between August 2009 and November 2015. Thirty-two variables for predicting bacterial meningitis were assessed. They covered epidemiological, comorbidity, clinical and analytical factors. Multivariate logistic regression analysis was performed.

Results: The study included 154 patients. The diagnosis was bacterial meningitis in 53 (34.4%) patients. Four variables were significantly associated with bacterial aetiology: cerebrospinal fluid (CSF) lactate concentration ≥33mg/dl (odds ratio [OR] 50.84; 95% confidence interval [CI]: 21.63-119.47, P<.001), serum procalcitonin (PCT) ≥0.8ng/ml (OR 46.34; 95%CI: 19.71-108.89; P<.001), CSF glucose <60% of blood value (OR 20.82; 95%CI: 8.86-48.96; P=.001), CSF polymorphonuclears greater than 50% (OR 20.19; 95%CI: 8.31-49.09; P=.002]. The area under the curve for the model serum PCT≥0.8ng/ml plus CSF lactate ≥33mg/dl was 0.992 (95%CI: 0.979-1; P<.001), and achieved 99% sensitivity and 98% specificity for predicting bacterial meningitis.

Conclusions: Serum PCT with CSF lactate, CSF glucose and CSF polymorphonuclears evaluated in an initial assessment in the ED for patients with AM, achieved an excellent diagnostic usefulness for predicting bacterial meningitis.