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. Half of all traumatic brain injuries occur in patients between 15-34 years of age. Men are more likely to suffer a head-injury than women.

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

More on brain injuries

How can they be treated?

Over 50,000 people in the US die from a TBI every years, and an estimated 275,000 people are hospitalized. Millions live with a TBI-related disability. There are short-term things medicine can do and long-term rehabilitation can help survivors. It is estimated that 40% of people with brain injuries are able to return to their jobs after one or two years.

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 involve medications and/or neurosurgery.

Pathophysiology of TBI

Epidemiology of brain injury

In the United States there are over 1 million cases of traumatic brain injury occurrences reported every year. Between 75-95 percent of those cases are mild TBI (traumatic brain injury) injuries. Many cases go unreported. About 200,000 people need to go to the hospital every year because of TBI, and 52,000 die, making TBI responsible for 40% of deaths from trauma.

In the United States:
1) Automobile accidents cause an estimated 45% of traumatic brain /> 2) Occupational incidents cause 10%.
3) Physical assaults cause 5%.
4) Slips and falls cause 30%.
5) Recreational activities cause an estimated 10%.

Brain injuries in young adults and children are usually from motor vehicle accidents, although the trend in this area is good with increased use of car safety belts and bicycle helmets. Kids in the age range 0 to 14 have about half a million TBIs in the US every year. Traumatic brain injuries suffered in contact sports and can also have lasting and even severe consequences. Football, soccer, rugby, hockey and boxing yield a high number of head injuries and the athletic organizations are working on better player safety equipment and better athletic training. The NFL is working on helmets designed to better absorb shock.

It is difficult to say how many people are living with TBI. A government study almost 20 years ago put the number at between 2.5 million and 6.5 million in the US.

Mild brain injuries and concussions are more common; it is estimated that 42 million people worldwide get them every year.