Contusions are a form of bruising or mild bleeding. In the event of head injuries resulting in TBI, a contusion typically accompanies a concussion, and when it does not heal on its own, it may become a hematoma. The severity of a contusion on the brain depends on its location and size.
3. Coup-Contrecoup Brain Injury
As the French words coup, meaning blow, and contrecoup, meaning counterblow, imply, a coup-contrecoup brain injury is actually two separate injuries. These are most common in car accidents where a person’s head hits a hard surface, such as the steering wheel or window, and the brain collides with the skull at the place of impact before bouncing back and hitting the other side of the skull. The coup injury is the initial injury from the point of impact, and the rebound causes the contrecoup injury.
4. Diffuse Axonal Injury
A diffuse axonal injury (DAI) occurs when a violent shake or twist of the brain causes cerebral tissue to slide back and forth until the axons, or connecting fibers, tear. Medical professionals refer to these tears as axonal shearing, and it can result in a loss of brain function. The severity of a DAI depends on the size and location of the tears. Larger, more numerous tears result in more serious effects. DAIs are among the most serious traumatic brain injuries.
5. Intracranial Hematomas
An intracranial hematoma is the collection of blood outside of the blood vessels. These sometimes take days or weeks to develop and are potentially deadly if left untreated.
The most common types of hematomas are:
- Intracerebral hematoma, which occurs in the brain
- Epidural hematoma, which occurs between the brain and skull
- Subdural hematoma, which occurs between the brain and the thin layer surrounding it
A hematoma usually shows up in the medical imaging an auto accident doctor orders following a collision.
6. Penetrating Brain Injury
A penetrating brain injury occurs when an object penetrates the skull and brain. These are less common in auto accidents, but people who have suffered penetrating head wounds have a higher likelihood of developing epilepsy and needing long-term treatment for traumatic brain injuries.
Uncontrolled bleeding in or around the brain is brain hemorrhage. The two types are subarachnoid hemorrhages, which occur outside of the brain in the surrounding area, and intracerebral hemorrhages, which occur inside the brain.
8. Recurrent Traumatic Brain Injury
Second impact syndrome, or recurrent traumatic brain injury, occurs when a person suffers two brain injuries within a short period of time. The second injury typically causes more damage and is sometimes overlooked if the person did not lose consciousness after the second.