Sermkiat Lolak1, Krishnapundha Bunyaratavej. 1. Department of Neurosurgery, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. macsermkiat@yahoo.com
Abstract
BACKGROUND: C-reactive protein (CRP) is an inflammatory marker believed to be of value in the early detection of meningitis. We evaluated its potential as a marker for prediction of shunt-related infection in high-risk subjects. METHODS: We conducted a prospective pilot study in 26 ventriculoperitoneal shunt procedures; 18 of the patients were considered to be at high risk of infection at the time of shunt insertion. All patients were screened for other disease that could cause, an increase in CRP. RESULTS: The serum CRP medians were 3.90 mg/L in the whole sample and 5.36 mg/L in the high-risk participants. All four shunt infections occurred in the high-risk group (22.2% of the group), three (75%) of which were in patients with meningitis. The logistic regression model showed that CRP concentrations above the cut-off value of ≥ 7 mg/L were related to shunt infection (p=0.042). The receiving-operating characteristic curve revealed a cutoff point at ≥ 10.1 mg/L (sensitivity 0.75, 1 - specificity 0.18). The calculated area under the curve was 0.744. The sensitivity and specificity in the whole sample and high-risk group were not different (75% and 79%-80%, respectively). The positive post-test probability was 40% in the whole sample and 50% in the high-risk group. The negative post-test probability was 5% and 7%, respectively. CONCLUSION: Our data suggest that in a patient at high risk of shunt-related infection, the serum CRP concentration can be a valuable predictor of the risk of infection. Further studies in larger samples would be worthwhile.
BACKGROUND:C-reactive protein (CRP) is an inflammatory marker believed to be of value in the early detection of meningitis. We evaluated its potential as a marker for prediction of shunt-related infection in high-risk subjects. METHODS: We conducted a prospective pilot study in 26 ventriculoperitoneal shunt procedures; 18 of the patients were considered to be at high risk of infection at the time of shunt insertion. All patients were screened for other disease that could cause, an increase in CRP. RESULTS: The serum CRP medians were 3.90 mg/L in the whole sample and 5.36 mg/L in the high-risk participants. All four shunt infections occurred in the high-risk group (22.2% of the group), three (75%) of which were in patients with meningitis. The logistic regression model showed that CRP concentrations above the cut-off value of ≥ 7 mg/L were related to shunt infection (p=0.042). The receiving-operating characteristic curve revealed a cutoff point at ≥ 10.1 mg/L (sensitivity 0.75, 1 - specificity 0.18). The calculated area under the curve was 0.744. The sensitivity and specificity in the whole sample and high-risk group were not different (75% and 79%-80%, respectively). The positive post-test probability was 40% in the whole sample and 50% in the high-risk group. The negative post-test probability was 5% and 7%, respectively. CONCLUSION: Our data suggest that in a patient at high risk of shunt-related infection, the serum CRP concentration can be a valuable predictor of the risk of infection. Further studies in larger samples would be worthwhile.