The indication of cranial computed tomography (CCT) is difficult to define for patients with mild traumatic brain injury (mTBI). For mTBI patients with a medium risk of intracranial complications, CCT scans are indicated although 90% of them are normal.

The interest of the S100B protein has been widely demonstrated in the management of mTBI in adults. Its serum concentration (for blood sampling drawn less than 3 hours after trauma) can accurately predict a normal CCT scan for mTBI patients with a medium risk of intracranial complications. That's why, serum assay of the S100B protein is routinely used in the Emergency Department of Clermont-Ferrand University Hospital for the treatment of patients with mTBI.

The objective of the study is to optimize the management strategy for mTBI patients by blood testing of new brain biomarkers. These biomarkers are synthesized by brain cells and are released into the blood in case of intracranial lesions.

Other biomarkers of brain damage, involved in the pathophysiology of head trauma, are also known. These are, for example, GFAP (Glial Fibrillary Acidic Protein), UCH-L1 (Ubiquitine Carboxy Terminal Hydrolase L1), NSE (Neurone Specific Enolase), Tau, SBDP (Spectrin Breakdown Products) or NFL (Neurofilament) protein. To date, the too limited number of studies doesn't enable the use of these biomarkers routinely. Therefore we will study the interest of these biomarkers in the management of adult patients' mTBI. We wish to set a collection of biological samples drawn from 1500 patients consulting for mTBI (with a medium risk of intracranial complications) at the Emergency Department of Clermont-Ferrand University Hospital, and requiring an assay of the S100B protein.

The study will take place over a period of 36 months at Clermont-Ferrand University Hospital. Patients cared for mTBI when they come to the Emergency Department will be recruited according to the inclusion criteria. In case of no opposition, when having their blood drawn, one more tube will be drawn per patient. Then, the obtained serum will be frozen at -80 ° C for the next assays of the cerebral biomarkers such as: GFAP, UCH-L1, NSE, Tau, SBDP, NFL, etc. A later 2-weeks' telephone call after the head trauma will be made by a member of the staff of the Department of Biochemistry and Molecular Genetics.

Inclusion Criteria:

• Male and female patient, major
• Patient admitted to the Emergency Department for mTBI, with a medium risk of intracranial lesions according to the SFMU (French Emergency Medicine Society) criteria, for which an S100B protein assay is indicated:
• GCS score of 15 with at least one associated risk factor: amnesia facts more than 30 minutes before the mTBI loss of consciousness, anti platelet aggregating agent
• Time between mTBI and blood draw (for the S100B protein assay) less than 3 hours.
• Patient covered by a Social Security scheme.

Exclusion Criteria:

• Patient classified in the high risk group of intracranial lesions according to SFMU criteria :
• GCS score less than 15, 2 hours after the trauma
• Focused neurological deficit
• Post-traumatic convulsion
• Suspicion of open fracture of the skull or embarrassment
• Any sign of fracture of the base of the skull (hemotympanum, bilateral periorbital bruise, otorrhea or rhinorrhea of cerebrospinal fluid)
• Treatment with anticoagulants
• More than one episode of vomiting.
• Patient classified in the group at low risk of intracranial lesions according to the SFMU criteria, presenting a GCS score of 15 without any criteria for moderate or high risk groups of intracranial lesions.
• Patient consulting for moderate or severe head trauma (GCS score less than 13).
• Refusal of the patient (signature of the opposition form).

Patients with mild Traumatic Brain Injury