Cerebrospinal Fluid Procalcitonin-A Potential Biomarker for Post-Craniotomy Bacteria Meningitis

Background: The literature regarding the utility of cerebrospinal fluid (CSF) procalcitonin (PCT) in the diagnosis of post-craniotomy bacterial meningitis and differentiating it from aseptic meningitis is sparse. Materials and Methods: CSF total WBC count, sugar, protein, and PCT were measured in febrile patients with suspected post-craniotomy meningitis during the first 30 days following an intradural cranial procedure for non-trauma indications. Patients were diagnosed as postoperative bacterial meningitis if CSF culture was positive (PBM, n= 28) or postoperative aseptic meningitis if CSF culture was sterile and there was no evidence of systemic infection (PAM, n = 31). CSF cytochemical parameters and PCT values were compared between the groups. Normal values of CSF PCT were obtained from 14 patients with noninfectious indications with hydrocephalus. Results: There was no significant difference in CSF total WBC count, sugar, and protein levels between PAM and PBM groups. The median PCT level in CSF in the normal group was 0.03 ng/mL (interquartile range [IQR] 0.02-0.07 ng/mL). CSF PCT in the PBM group (median 0.37 ng/mL, IQR 0.2-1.4 ng/mL) was significantly higher than normal values as well as PAM group (median 0.12 ng/mL, IQR 0.07-0.26 ng/mL (P= 0.0004). The area under the receiver operating characteristic (ROC) curve for CSF PCT was 0.767. A cutoff value of 0.12 ng/mL yielded a sensitivity of 85.7% (95% CI: 67.3% to 96%), specificity of 51.6% (95% Cl: 33% to 69.9%), positive predictive value of 61.5% (95% CI: 51.9% to 70.3%), and negative predictive value of 80% (95% CI: 60.3.8% to 91.3%). Conclusions: CSF PCT assay in patients who are febrile during the first 30 days post-non-trauma neurosurgical procedures has a role in the early diagnosis of bacterial meningitis.