Head injury outcome prediction: A role for protein S-100B?

Introduction: Prediction of the likely outcome of head injury from the outset would allow early rehabilitation to be targeted at those with most to gain. Clinical evaluation of a head injured patient may be confounded by intoxicants such as alcohol. Imaging modalities are insensitive (CT) or impractical (MR) for screening populations of such patients. A peripheral marker that reflected the extent of brain injury might offer an objective indication of likely adverse sequelae. This review evaluates the evidence for Protein S-100B as such a marker. Methods: A search of published literature revealed 18 studies designed to evaluate the relation between serum S-100B and measures of outcome after head injury. Results: A cut-off point of 2.5 μg/L is related to dependent disability in those presenting with low conscious level, and may be a specific test for this. There appears to be a relation between initial serum S-100B concentration and measures of disability as well as post-concussion symptoms for those with seemingly mild injuries. There does not appear to be a relation between S-100B and measures of neuropsychological performance. Conclusion: Patients with high levels of S-100B at initial assessment (>2.5 μg/L) may represent a high risk group for disability after head trauma.