Peripheral white blood cell counts and bacterial meningitis: implications regarding diagnostic efficacy in febrile children.

In order to investigate the clinical value of peripheral white blood cell variables for the diagnosis of bacterial meningitis among young, febrile children, we compared total peripheral white counts, total segmented neutrophil counts, total band counts, and the ratio of immature-to-total neutrophils (I:T ratio) among 46 children with bacterial meningitis, 130 children with aseptic meningitis, and 56 febrile children with culture confirmed extrameningeal bacterial infection. Children with bacterial meningitis were comparable to those with aseptic meningitis with respect to median total white blood cell counts and median total segmented neutrophil counts but had a significantly higher median total band count (1760/microliters vs 378/microliters, P = 0.0001) and a significantly higher median I:T ratio (0.40 vs 0.09, P less than 0.001). In contrast, children with bacterial meningitis were comparable to those with an extrameningeal bacterial infection with respect to median total band count but had a significantly lower median total peripheral white count (10,650/microliters vs 15,300/microliters, P = 0.0013), a lower median total segmented neutrophil count (4511/microliters vs 6796/microliters, P = 0.023), and a significantly higher median I:T ratio (0.40 vs 0.15, P less than 0.001). Children with meningitis who were bacteremic at presentation had a significantly lower total white cell count (P = 0.001) and significantly higher I:T ratio (P = 0.005) when compared with children who had an extrameningeal infection and concurrent bacteremia at presentation.(ABSTRACT TRUNCATED AT 250 WORDS)