S100B serum protein cannot predict secondary intracranial haemorrhage after mild head injury in patients with low-dose acetylsalicylic acid prophylaxis

Abstract

Introduction: The goal of this study was to investigate if S100B serum protein could predict secondary intracranial haemorrhagic events (SIHEs) after mild head injury (mHI) in patients taking low-dose acetylsalicylic acid (LDA), making routinely repeated head computed tomography (RRHCT) scans unnecessary.

Methods: Three hundred and eight-two patients with mHI, older than 60 years and taking LDA prophylaxis were enrolled. Primary head CT and RRHCT scans within 3 and 48 hours to trauma were performed. Additionally, S100B serum protein levels were evaluated at admission and predictive power for SIHEs was analysed.

Results: Fifty-nine per cent were female and the mean age of all included patients was 81.8 ± 8.9 years. In four patients SIHEs were diagnosed. Sensitivity and the negative predictive value of S100B serum protein (cut-off value 0.10 µg l⁻¹) were 75.0% and 98.6%, respectively. Specificity was 19.0% and the positive predictive value 1.0% (306 false positive values). In patients without bleeding, the median S100B value was 0.18 (IQR = 0.12–0.34) and in the ones with SIHEs, the median was 0.11 (IQR = 0.10–1.16) (p > 0.05). The discriminatory power of S100B in the ROC analysis was 0.399 (95% CI = 0.079–0.720; p > 0.05).

Conclusion: S100B cannot be considered as an effective diagnostic tool in the prediction or exclusion of SIHE in older patients with mHIs taking LDA prophylaxis.

• Head computed tomography
• receiver operating characteristic curve

Acknowledgements

Foremost, Lukas Ernstbrunner would like to thank Philipp Moroder, MD, at the Department for Traumatology and Sports Injuries, Salzburg, for the possibility to work with him and the team of the department. His guidance helped throughout all the time of research. Furthermore, Ernstbrunner thanks Gundobert Korn, MD at the Department for Traumatology and Sports Injuries, Salzburg, who steadily supported his work and also guided him through the recent project. The same counts for Mark Tauber, Alexander Auffarth and Professor Herbert Resch (Head of the Department for Traumatology and Sports Injuries, Salzburg). Last but not least, Ernstbrunner thanks his father, Erich Ernstbrunner, MD, in his General Practitioner Office, Vienna, for his ideas, patience and help throughout the whole project.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.