Role of Cerebrospinal Fluid Lactate and C-Reactive Protein in Differential Diagnosis of Meningitis in Adults

Abstract

Introduction: Differentiating various types of meningitis is still a challenge as yield of microbiological tests are generally low in these disorders. Aim: To find out the role of Cerebrospinal Fluid (CSF) lactate and CSF C-reactive Protein (CRP) for the differentiation of bacterial, tuberculous and viral meningitis. Materials and Methods: A cross-sectional study was conducted in which 90 adult patients were included and in them CSF lactate and CRP measurements were done in 26 patients of tuberculous meningitis, 23 patients of bacterial meningitis and 43 patients of viral meningitis. Data were analysed using SPSS version 17.0. Descriptive statistics are represented using mean with standard deviation or median with interquartile range for continuous variable. Categorical data were represented using frequency with percentages. Continuous variable between the groups tested using ANOVA/Kruskal wallis test for more than two groups. Results: The mean CSF Lactate level in bacterial, tuberculous and viral meningitis was 10.67, 4.46 and 2.84 respectively. The mean CSF lactate level was significantly raised in bacterial compared to tuberculous and viral meningitis (p <0.001). In a pair wise comparison, the mean CSF lactate in bacterial meningitis group differed significantly from both viral (p-value <0.001) and TB meningitis (p-value <0.001). However, CSF lactate did not differ between viral and TB meningitis. With a cut-off value of 4.35 mmol/L, CSF lactate was useful in differentiating bacterial from tuberculous and viral meningitis with a sensitivity of 90.5% and specificity of 82.6%. The mean CSF CRP level in bacterial, tuberculous and viral meningitis was 4.44, 3.04 and 3.16, respectively. The difference was not significant (p-value 0.39). In a pairwise comparison, mean CSF CRP-value in bacterial meningitis did not differ from both viral meningitis and TB meningitis. Conclusion: Lactate levels in CSF can be used as a good rapid screening test to differentiate bacterial meningitis from nonbacterial meningitis like tuberculous and viral meningitis along with other CSF parameters.

Keywords

• bacterial meningitis
• tuberculous meningitis
• viral meningitis