The Effect of S-100B Protein and Risk Factors on Indication of Cranial Computed Tomography in Patients with Minor Head Injury

ABSTRACT

PURPOSE: S-100B protein is a reliable biomarker of brain injury. The clinical decision rules for screening of a cranial computed tomography (CCT) in minor head injury patients remain controversial. The purpose of this study was to determine whether S-100B protein and risk factors for minor head injury patients can provide meaningful insights to improve initial CCT scanning of patients with MHI. METHODS: Fifty patients with MHI were enrolled in this prospective study from July 2007 to September 2007. All patients who fulfilled the following inclusion criteria were enrolled history of head trauma, initial GCS score of 14 to 15, and one or more clinical findings. Risk factors of patients presented in this study included age younger than 2 years or above sixty years, focal neurologic deficit (FND), post-traumatic seizure, skull fracture, extra-cranial injury, coagulopathy, previous neurologic deficit and ingestion of toxicants (drugs or alcohol). A venous blood sample for assessment of S-100B protein was drawn and a CCT scan was undergone. The reference value of S-100B protein was 0.105 microgram/L. All CCT findings were confirmed by radiologists. RESULTS: Of the 50 patients studied, 15 patients exhibited trauma-relevant intracranial lesions on the CCT scan (CCTpositive). The subgroups of CCT-positive and -negative showed no statistically difference in S-100B level (p=0.068). Of the fifty patients, thirteen had no risk factors (RF). However, statistically significant differences were observed in S-100B level when the subgroups were classified into RF-positive and RF-negative groups (p=0.016). The CCTpositive findings of 13 patients with no RF were identified with 100% sensitivity, 54.6% specificity, 28.6% positive predictive value and 100% negative predictive value through assessment of S-100B protein level. CONCLUSION: In patients with MHI, S-100B protein level and risk factors may give us reliable predictive information prior to CCT screening in emergency department.