title: Secondary peaks of S100B in serum relate to subsequent radiological pathology in traumatic brain injury.
abstract: BACKGROUND
  Patients suffering from severe traumatic brain injury (TBI) often develop secondary brain lesions that may worsen outcome. S100B, a biomarker of brain damage, has been shown to increase in response to secondary cerebral deterioration. The aim of this study was to analyze the occurrence of secondary increases in serum levels of S100B and their relation to potential subsequent radiological pathology present on CT/MRI-scans.
  
  
  METHODS
  Retrospective study from a trauma level 1 hospital, neuro-intensive care unit. 250 patients suffering from TBI were included. Inclusion required a minimum of two radiological examinations and at least three serum samples of S100B, with at least one >48 h after trauma.
  
  
  RESULTS
  Secondary pathological findings on CT/MRI, present in 39 % (n = 98) of the patients, were highly correlated to secondary increases of ≥0.05 μg/L S100B (P < 0.0001, pseudo-R (2) 0.532). Significance remained also after adjusting for known important TBI predictors. In addition, secondary radiological findings were significantly correlated to outcome (Glasgow Outcome Score, GOS) in uni-(P < 0.0001, pseudo-R (2) 0.111) and multivariate analysis. The sensitivity and specificity of detecting later secondary radiological findings was investigated at three S100B cut-off levels: 0.05, 0.1, and 0.5 μg/L. A secondary increase of ≥0.05 μg/L had higher sensitivity (80 %) but lower specificity (89 %), compared with a secondary increase of ≥0.5 μg/L (16 % sensitivity, 98 % specificity), to detect secondary radiological findings.
  
  
  CONCLUSIONS
  Secondary increases in serum levels of S100B, even as low as ≥0.05 μg/L, beyond 48 h after TBI are strongly correlated to the development of clinically significant secondary radiological findings.
authors.affiliation: Department of Clinical Neuroscience, Section for Neurosurgery, Karolinska Institutet, Karolinska University Hospital Solna, R2:02, 171 76, Stockholm, Sweden, eric.thelin@ki.se.
authors.forename: Eric P
authors.initials: EP
authors.lastname: Thelin
authors.forename: David W
authors.initials: DW
authors.lastname: Nelson
authors.forename: Bo-Michael
authors.initials: BM
authors.lastname: Bellander
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology*; D001930:Brain Injuries / Q000097:blood* / Q000150:complications / Q000000981:diagnostic imaging; D015600:Glasgow Coma Scale; D023261:Glasgow Outcome Scale; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D064568:S100 Calcium Binding Protein beta Subunit / Q000097:blood*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D015415:Biomarkers; D064568:S100 Calcium Binding Protein beta Subunit