C-reactive protein is useful in distinguishing Gram stain-negative bacterial meningitis from viral meningitis in children

Objective: To clarify to what extent Gram stain-negative bacterial meningit is can be distinguished from viral meningitis by assessment of cerebrospina l fluid (CSF) and blood indices and serum C-reactive protein (CRP) in child ren over 3 months of age. Design: Common CSF indices, blood leukocyte counts, and serum CRP Values we re compared between patients with bacterial meningitis who had a positive C SF bacterial culture but a negative Gram stain and patients with viral meni ngitis. Population: Three hundred twenty-five consecutive patients with CSF culture -proven bacterial meningitis, for whom Gram stain was negative in 55 cases, and 182 children with proven or presumed viral meningitis. Results: Significant differences between patients with bacterial and viral meningitis were found in all indices with large overlap in all except serum CRP. In patients with bacterial meningitis, the mean CSF glucose concentra tion, protein concentration, leukocyte count, blood leukocyte count, and se rum CRP were 2.9 mmol/L (52 mg/dL), 1.88 g/L, 4540 x 10(6)/L, 18.0 x 10(9)/ L, and 115 mg/L; and in those with viral meningitis, mean values were 3.3 m mol/L (59 mg/dL), 0.52 gn, 240 x 10(6)/L, 10.6 x 109/L, and <20 mg/L, respe ctively. Of the tests investigated in this study, only serum CRP was capabl e of distinguishing Gram stain-negative bacterial meningitis from viral men ingitis on admission with high sensitivity (96%), high specificity (93%), a nd high negative predictive value (99%). Conclusion: Exclusion of bacterial meningitis with only the conventional te sts is difficult. Combined with careful physical examination and CSF analys es, serum CRP measurement affords substantial aid.