In community-acquired bacterial meningitis(CABM) intracranial vascular alterations are devastating complications which are triggered by neuroinflammation and result in worse clinical outcome. The neutrophil-to-lymphocyte ratio(NLR) represents a reliable parameter of the inflammatory response. So far, in CABM-patients the association between NLR and elevated cerebral blood flow velocity(CBFv) remains unclear.
This study included all (CABM)-patients admitted to a German tertiary center between 2006-2016. Patient demographics, in-hospital measures and neuroradiological data were retrieved from institutional databases. CBFv was assessed by transcranial Doppler sonography transcranial doppler(TCD). Patients’, radiological and laboratory characteristics were compared between patients with/without elevated CBFv. Multivariate-analysis investigated parameters independently associated with elevated CBFv. Receiver operating characteristic(ROC-)curve analysis was undertaken to identify the best cut-off for NLR to discriminate between increased CBFv.
108 patients with CABM were identified. 27.8%(30/108) showed elevated CBFv. These patients had a worse clinical status on admission(Glasgow Coma Scale:12[9-14vs.14[11-15]; p=0.005) and required more often intensive care (30/30[100%]vs.63/78[80.8%];p=0.01).The causative pathogen was S. pneumoniae in 70%. These patients developed more often cerebrovascular complications with delayed cerebral ischemia(DCI) within hospital stay(p=0.031). A significantly higher admission-NLR was observed in patients with elevated CBFv(median[IQR]:elevated CBFv:24.0[20.4-30.2]vs. normal CBFv:13.5[8.4-19.5];p<0.001). After adjusting for significant parameters in univariate testing, NLR on admission was significantly associated with increased CBFv(Odds ratio[95%CI]:1.042[1.003-1.084];p=0.036). ROC-analysis identified a NLR of 20.9 as best cut-off value to discriminate between elevated CBFv(area under the curve=0.713, p<0.0001,Youden's Index=0.441;elevated CBFv:NLR>20.9 19/34[55.9%]vs.NLR<20.9 11/74[14.9%];p<0.001).
Intracranial vascular complications are common among CABM-patients and are a risk factor for unfavorable outcome at discharge. NLR is independently associated with elevated CBFv.