Effects of Head and Extracranial Injuries on Serum Protein S100B Levels in Trauma Patients

摘要

Background: Serum protein S100B determinations have been recently suggested as markers of traumatic brain injury. However, little is known about the effects of extracranial injuries on S100B levels in trauma patients.Methods:We studied 224 patients with head trauma (54 of whom also had extracranial injuries), 155 patients with various types of extracranial injuries, and 8 healthy pilots exposed to high Gz forces. The head trauma patients had either no brain injury (n = 35), mild brain injury (n = 165), or moderate to severe brain injury (n = 24). The extracranial injuries were divided into small and large injuries. Serum protein S100B levels were determined from samples taken within 6 hours after the trauma event.Results:The head trauma patients had a significantly higher median S100B (0.17mug/L) than the patients with extracranial injuries (0.07mug/L) (p < 0.001). Serum S100B levels also correlated with the severity of brain injury (p < 0.001), the highest values occurring in the patients with moderate to severe brain injury (1.27mug/L). However, large extracranial injuries also elevated S100B levels (0.35mug/L), whereas small extracranial injuries in the absence of head trauma did not significantly affect S100B levels (0.07 mug/L). Above the cutoff level of 0.13mug/L, there were 61% of the head trauma patients and 26% of those with extracranial injuries (Pearson x~2 test,p< 0.001). However, only 4% of the patients with purely extracranial injuries had a concentration of S100B above the cutoff level of 0.50 mug/L, whereas the head trauma patients with moderate to severe brain injury exceeded this cutoff in 67% of the cases. Exposure to high Gz forces did not influence serum S100B levels in healthy individuals.Conclusion:We conclude that serum S100B is a sensitive marker of brain injury, which correlates with the severity of the injury. Large extracranial injuries also elevate S100B levels. However, S100B has a high negative predictive power, and the finding of a normal S100B value shortly after trauma should thus exclude significant brain injury with a high accuracy.