A primary brain injury occurs at the time of initial mechanical trauma. An additional secondary brain injury begins immediately after impact. Inflammatory and neurotoxic processes result in raised intracranial pressure, decreased cerebral perfusion and ischaemia. This secondary injury is worsened by further physiological insults such as hypotension and hypoxia.

Assessment of the patient begins with an ABCD approach and should take place alongside resuscitation. Airway management is the priority, and this must be safely secured when indicated. Cervical spine injury is often associated with a head injury. The neck should be immobilised. Hypoventilation causes hypoxia and hypercapnia. Controlled ventilation to achieve a PaCO2 of 4.5 - 5 kPa and a PaO2 of > 13 kPa is recommended to control intracranial pressure. Hypotension reduces cerebral perfusion; a mean arterial pressure of > 90 mmHg should be targeted. Neurological assessment is undertaken using the Glasgow Coma Scale (GCS). A GCS less than 8 is considered a serious head injury and is often an indication for tracheal intubation. Other indications are described. Transfer to a neurosurgical unit is often required. Safe transfer guidelines must be followed.