Types of Traumatic Brain Injury
There are various types of traumatic brain injury, each of which can elicit serious after effects. Effective, life-saving treatment for traumatic brain injury depends on understanding brain injury's many forms. In what manner the head has been hit and with how much force the head has been hit dictate brain injury type. Head injuries are either open or closed, and injury to the brain itself is either diffuse axonal or focal brain injury.
Open Head Injury
Open head injury refers to skull fracture by blunt force or skull penetration by an object. Traumatic brain injury can result from brain tissue infection, brain tissue penetration, or laceration by an object or skull fragments. Infection is a common consequence. Open head injury can expose brain tissue to the environment, inviting viral and bacterial contamination of the tissue and wound. Brain tissue penetration or laceration by objects or skull fragments is common because the fractured skull can no longer protect delicate brain tissue.
Closed Head Injury
Even if the skull has not been fractured or penetrated, the brain can be injured. This is called closed head injury. Intense rotational forces, forceful head shake (whiplash), or blunt force can cause the brain to violently collide with the inside of the bony skull. A dangerous closed head injury complication is increased intracranial pressure. As there is no skull opening in closed head injury, brain swelling pressure has nowhere to escape and rapidly builds. An increase of intracranial pressure not only damages tissue, but it also prevents adequate oxygen and blood flow through the brain. Without blood and oxygen, the brain dies.
Diffuse Axonal Brain Injury
One of the most common and devastating types of traumatic brain injury is diffuse axonal brain injury. Diffuse brain injury is characterized by microscopic damage that occurs in several different parts of the brain. Nerve fibers such as axons are sheared and destroyed, preventing the nerve cells from communicating with each other to carry out brain functions. Hypoxic-ischemic injury (HII) is often a complication of diffuse axonal injury. When the brain swells, blood and oxygen flow is restricted, and hypoxic-ischemic injury occurs. Without oxygen, further brain damage or brain death is imminent.
Focal Brain Injury
Focal brain injury is damage to one part of the brain or damage at the point where an object, like a bullet or skull fragment, enters brain tissue. Errant bone shards from skull fractures that penetrate brain tissue can also cause focal brain injury.
The type, location, and severity of the brain injury can forecast the extent of brain damage or disability. Any type of traumatic brain injury can cause severe disability or neurological impairment. In more serious cases, a traumatic brain injury victim can succumb to coma, vegetative states, or death.
Each type of traumatic brain injury has unique symptoms, complications, and treatments. Please read other articles on the site to learn more about traumatic brain injury.
[Last revision: July 2009]