Serum S100B Levels Can Predict Computed Tomography Findings in Paediatric Patients with Mild Head Injury

Abstract

Introduction: Traumatic brain injuries (TBIs) are very common in paediatric populations, in which they are also a leading cause of death. Computed tomography (CT) overuse in these populations results in ionization radiation exposure, which can lead to lethal malignancies. The aims of this study were to investigate the accuracy of serum S100B levels with respect to the detection of cranial injury in children with mild TBI and to determine whether decisions regarding the performance of CT can be made based on biomarker levels alone.

Materials and methods: This was a single-center prospective cohort study that was carried out from December 2016 to December 2017. A total of 80 children with mild TBI who met the inclusion criteria were included in the study. The patients were between 2 and 16 years of age. We determined S100B protein levels and performed head CTs in all the patients.

Results: Patients with cranial injury, as detected by CT, had higher S100B protein levels than those without cranial injury (p < 0.0001). We found that patients with cranial injury (head CT+) had higher mean S100B protein levels (0.527 μg L^-1, 95% confidence interval (CI) 0.447-0.607 μg L^-1) than did patients without cranial injury (head CT-) (0.145 μg L^-1, 95% CI 0.138-0.152 μg L^-1). Receiver operating characteristic (ROC) curve analysis clearly showed that S100B protein levels differed between patients with and without cranial injury at 3 hours after TBI (AUC = 0.893, 95% CI 0.786-0.987, p = 0.0001).

Conclusion: Serum S100B levels cannot replace clinical examinations or CT as tools for identifying paediatric patients with mild head injury; however, serum S100B levels can be used to identify low-risk patients to prevent such patients from being exposed to radiation unnecessarily.

Figure 1

Box-and-whisker plots of serum S100B levels (μg/L) in patients with and without cranial injury. ^∗An extreme value within group.

Figure 2

Box-and-whisker plots of serum S100B levels (μg/L) according to the number of cranial injuries observed on CT: no cranial injury (No), one cranial injury (1), two cranial injuries (2), three cranial injuries (3), four cranial injuries (4), and five cranial injuries (5). ^∗An extreme value within group.

Figure 3

S100B serum concentrations according to patient GCS scores upon admission to the emergency department. This graph groups the median (and interquartile range) serum S100B concentrations according to the patients' initial GCS scores upon their admission to the emergency department. The black squares indicate the concentrations of the patients without cranial injury (CT−), and the open squares indicate the concentrations of the patients with cranial injury (CT+). S100B concentrations were significantly increased in the patients with cranial injury (CT+) compared with those in the patients without cranial injury (CT−) in each GCS group (^∗p < 0.001 in the U test, CT+ versus CT−). Among the patients with cranial injury (CT+), S100B concentrations in the patients with GCS scores of 15 were significantly lower than those in the patients with GCS scores of 13 or 14 (p < 0.05 in ANOVA followed by Dunn's post hoc test for multiple comparisons). Among the patients without cranial injury (CT−), no significant differences were observed in S100B concentrations in the patients with GCS scores of 13, 14, or 15.

Figure 4

ROC analysis comparing sensitivity and specificity 3 h after TBI.