How does extracerebral trauma affect the clinical value of S100B measurements?

BACKGROUND: Protein S100B has proven to be a useful biomarker for cerebral damage. The predictive ability of S100B may, however, be affected by extracerebral injuries. The aim of this study was to investigate serum levels of S100B in patients with either isolated head injury (IHI), multi trauma with head injury (MTHI), or no head injury (NHI). The primary aim was to assess if a significant difference in serum levels of S100B could be found between IHI and MTHI patients. METHODS: Patients (233) were primarily admitted to the trauma centre. Serum samples were drawn on admission and 6 h after trauma and then stored at −80°C until analysed. Variables included Abbreviated Injury Scale (AIS) for head trauma, Injury Severity Score (ISS) and 30-day survival. RESULTS: Two patients could not be classified. IHI occurred in 28, MTHI in 102 and NHI was found in 101. The median S100B concentrations on arrival were 0.47, 1.68 and 0.49 μg/l, respectively (p<0.0001). The corresponding values at 6 h were 0.14, 0.31 and 0.15 μg/l, respectively (p<0.0001). S100B was significantly higher in patients with MTHI than in patients with IHI at both time points (p values 0.0005 and 0.01). There was no significant difference in S100B between patients having IHI and patients with NHI (p=0.81 and p=0.67). CONCLUSIONS: High serum levels of S100B were found early after trauma. The highest concentrations of S100B were found in patients with multi trauma. This suggests that S100B serum concentrations are significantly affected by extracerebral injuries.