[B] serum procalcitonin level may discriminate bacterial and viral meningitis in children

Acute childhood meningitis is a life threatening condition often leaving the survivors with neurological impairments. Latex agglutination test is negative in early meningitis cases and is unreliable in the detection of St. pneumoniae, Staphylococci, H. influenzae and Enteric bacilli. Antibiotic treatment should not be deferred until awaiting the result of CSF cultures, nor aggressive antimicrobials should be given unnecessarily in cases of viral meningitis. Procalcitonin [PCT] is a potentially sensititve and rapid marker for invasive bacterial infections but remains low in viral infections. We aimed to assess the reliability of serum PCT in differentiating bacterial from viral meningitis in children. We measured serum PCT and C-reactive protein [CRP] levels and cerebrospinal fluid [CSF] total protein [TP], and absolute neutrophil count [ANC] in fifty children admitted for meningitis. Bacterial cultures of CSF were positive in 17 children [group of bacterial meningitis] and 33 patients were diagnosed as acute viral meningitis. Serum PCT levels were measured by immunoluminometric assay: "BRAHMS Diagnostica, Berlin". CRP levels were determined by rate nephelometry. PCT and CRP levels and CSF ANC and TP were significantly higher [P< 0.001] in the group of bacterial meningitis than the group of viral meningitis. Assay of serum CRP and CSF proteins and cells showed a zone of overlapping values between the two groups. Receiver operating characteristic [ROC] curves were plotted for serum PCT and CRP levels to determine the optimal cut off points that maximized the sum of the sensitivity and specificity of each test. A serum PCT level of 2microg/l was retained as the diagnostic threshold since at this value both the sensitivity and negative predictive value [NPV] were 100%. Area under the receiver operating characteristic curve [AUROCC] was 1.0 for PCT which was significantly higher than that for CRP [0.93; P< 0.05]. These data suggest that serum PCT at the cut off value 2microg/l might be discriminant of bacterial and viral meningitis in children