C-reactive protein in cerebrospinal fluid and serum: A paraphernalia in the diagnosis of pyogenic meningitis

Meningitis is one of the commonest and most feared neurological diseases in children and adults with high morbidity and mortality. Analysis of cerebrospinal fluid (CSF) in meningitis by routine tests does not always provide rapid definite information as far as causative agent is concerned and there is need for additional tests on CSF. Estimation of CSF C-reactive protein (CRP) and comparing it with the levels of serum CRP levels can overcome this difficulty. In view of this background, the present study was undertaken to evaluate the sensitivity of CRP in CSF and its relation to the serum values. 32 cases of pyogenic meningitis between 18 to 65 years and 28 individuals undergoing lumbar puncture for various surgical procedures were taken as controls from Neurology department of Government General Hospital, Vijayawada. Lumbar puncture was done in all cases and CSF was collected in sterile bottles and blood was drawn within 1 hour of lumbar puncture. Analysis of the samples was done in the Departments of Biochemistry, Microbiology and Pathology of Siddharta Medical College, Vijayawada. CRP was estimated using Latex Slide Agglutination semi quantitative method (Accurex). ANOVA, Chi-Square test and Z test were used for statistical analysis. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) was defined for each test. Receiver operating characteristic (ROC) curves were plotted. CSF protein was significantly high and CSF/serum ratio was altered. In majority of cases CSF sugar was less than 2/3 of blood sugar and absent in many of them. CRP was positive in almost all cases and was in the range of 0.6 to 9.6 mg/dl and values were corresponding in the serum. CSF CRP is a novel marker with high sensitivity and specificity. CRP can be used as a supportive evidence of meningitis, as these tests are cost-effective and it can be used on regular basis along with other routine tests to diagnose pyogenic meningitis in adults.