Traumatic Brain Injuries
Traumatic brain injury (TBI) is any injury to the brain caused by trauma to the head. Motor vehicle accidents are the major cause of TBI in people under age 75. These include accidents involving automobiles, motorcycles, bicycles, and pedestrians. About twenty percent of TBIs are due to violence, such as gunshots and child abuse, and three percent are due to sports injuries.
A blow or jolt to the head can cause a type of mild brain injury called a concussion. Some symptoms of a concussion are:
- Persistent low-grade headaches
- Having more trouble than usual remembering things, concentrating, or making decisions
- Feeling tired all the time
- Feeling sad, anxious, or listless
- Becoming easily irritated for little or no reason
An April 2008 Rand study found 19% of United States military personnel returning from Iraq and Afghanistan reported possible traumatic brain injuries. A researchers called the prevalence of TBI "a major health crisis". Most military members who suspect they got a TBI were not evaluated by a doctor.
Diffuse Axonal Injury
Neurons (cells in the brain and central nervous system) communicate with
each other via long fibers called axons. Diffuse axonal injury results from
microscopic tearing of these axons caused by stretching and twisting the
brain. Torn axons release chemicals that are toxic to nearby neurons, creating
additional damage. Diffuse axonal injury can be caused by car accidents
(e.g., whiplash), concussions, or abusive or violent events (such as violently
shaking a baby). The symptoms of diffuse axonal injury depend on the severity
and location of tearing, and can include temporary or permanent cognitive
(thinking) impairment, fever, muscle rigidity, high blood pressure, coma,
or death. Treatment of diffuse axonal injury is designed to prevent additional
damage from occurring and can include medications and/or neurosurgery.