Is cerebrospinal fluid C-reactive protein a better tool than blood C-reactive protein in laboratory diagnosis of meningitis in children?

ABSTRACT

This study aimed to test whether C-reactive protein [CRP] measurement could differentiate between different types of meningitis and become a routine test. A prospective study included 140 children admitted to Manipal Teaching Hospital, Pokhara, Nepal, between July 2009 and June 2011. The subjects had a blood test and detailed cerebrospinal fluid [CSF] analysis, including blood and CSF CRP levels. Of those admitted, 31.1% had pyogenic meningitis [PM], 26.2% partially treated meningitis [PPM], 33% viral meningitis [VM], and 9.7% tubercular meningitis [TBM], with 26.4% controls. Organisms were isolated in 12.5% of the cases by blood culture and 25% of cases through CSF culture. Blood CRP was positive in all groups, with the highest values in PM [53.12 +/- 28.88 mg/dl] and PPM [47.55 +/- 34.34 mg/dl]; this was not statistically significant [P = 0.08]. The CSF CRP levels were significantly higher [P <0.001] in PM [45.75 +/- 28.50 mg/dl] and PPM [23.11 +/- 23.98 mg/dl]. The sensitivity and specificity of blood CRP was 90.62%, 88.88%, 64.7%, 70% and 32.4%, 30.97%, 24.52%, 26.12% and that of CSF CRP was 96.87%, 66.66%, 20.58%, 10% and 74.73%, 63.71%, 50.94%, 55.35% for PM, PPM, VM and TBM, respectively. Because of its high sensitivity, both CSF CRP and blood CRP can be used to screen for bacterial meningitis [both PM and PPM]. CSF CRP screening yielded results with a higher specificity than blood CRP; hence, it can be a supportive test along with CSF cytology, biochemistry, and microbiology for diagnosing meningitis