Traumatic Brain Injury

Traumatic brain injury, or TBI, is an acquired brain injury (ABI) caused by physical damage to the brain. This may be the result of a blow to the head or from the brain impacting with the skull via a whiplash motion of the head. Bruising, bleeding, swelling, or tearing of brain tissue may occur, as well as loss of consciousness.

Symptoms of TBIs range from temporary to permanent and from mild to severe. A sufferer may black out briefly after a punch to the head and then experience no more symptoms, or may remain unconscious for days or even years.

Like the symptoms, TBI effects may be temporary or permanent. They range from mild injury, such as being momentarily stunned while playing football, to a very severe injury that may cause prolonged loss of consciousness. 

Concussions are a form of mild TBI. Most sufferers will recover fully, but some experience lasting effects that may present significant challenges.

How the brain is injured

Three separate processes work to injure the brain in a traumatic event: bruising (bleeding), tearing, and swelling. In a traumatic brain injury, the soft tissue of the brain is propelled against the very hard bone of the skull and then bounced backwards. 

Blood vessels may tear, releasing blood into areas of the brain. The skull does not expand, so the blood begins to press on softer things like brain tissue. Brain tissue is very delicate and will stop working properly or may even die off.

This tearing of brain tissue can break the connections between neurons. This happens on a microscopic level and may not show up in standard medical tests.

Finally, the brain swells in the same way a damaged muscle does. This pressure pushes down on the brain and damages its structures. If there’s too much pressure, this can stop important functions like breathing or heart rate. Sometimes, doctors will install a “relief valve” to let off the excess pressure.

© 2015 BIC