Risk factors and prognostic indicators of bacterial meningitis in a cohortof 3580 postneurosurgical patients

In order to identify the incidence, risk factors and prognostic indicators of postneurosurgical bacterial meningitis, a 9-y retrospective cohort study was performed. The cohort comprised 3580 individuals who underwent neurosu rgical operations at the Department of Neurosurgery of Catholic University, Rome, a 1700-bed university hospital. We observed 52 episodes of postneuro surgical meningitis, with infection rates of 1.4/100 patients, 0.8/100 oper ations for craniotomies and 2.6/100 operations for internal cerebrospinal f luid (CSF) shunt or ventriculostomy with external drainage. The overall inf ection rate decreased from 2.5/100 operations in 1989 to 0.9/100 in 1997 (p = 0.03). Logistic regression analysis indicated that duration of ventricul ostomy with external drainage [p < 0.01; odds ratio (OR) = 9.67; 95% confid ence interval (CI) = 2.44-38.32] and increasing value of the APACHE III sco re (p < 0.01; OR = 8.51; 95% CI = 2.15-33.68) were independent risk factors for development of meningitis. The overall case fatality rate was 8%. Pred ictors of mortality were low ( < 1.66 mmol/l) CSF glucose concentration (p = 0.001), increasing value of the APACHE III score (p = 0.002) and Gram-neg ative aetiology (p = 0.003).