Head Trauma

General Principles

Traumatic brain injury (TBI) can occur with head injury due to contact and/or acceleration/deceleration forces.
Concussion: Trauma-induced alteration in mental status with normal radiographic studies that may or may not involve loss of consciousness.
Contusion: Trauma-induced lesion consisting of punctate hemorrhages and surrounding edema.

Closed head injuries may produce diffuse axonal injury.
Contusion or hemorrhage can occur at the site of initial impact, “coup injury,” or opposite to the side of impact, “countercoup injury.”
Penetrating injuries (including depressed skull fracture) or foreign objects cause brain injury directly.
Secondary increases in intracranial pressure may compromise cerebral perfusion.

Head injury is the most common cause of neurologic illness in young people.
The overall incidence of TBI in the US population is estimated at approximately 750 per 100,000 (i.e., approximately 2.5 million per year with approximately 11% requiring hospitalization).¹
Two-thirds of TBIs are considered “mild,” whereas 20% are severe and 10% are fatal. Note that although designated as “mild,” mild TBI can still translate into significant disability (permanent in 15%).
Rates of TBI are highest in the very young, adolescents, and the elderly.

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