Traumatic brain injury is when an external mechanical force causes brain dysfunction.

A violent blow or hit to the head or body can cause a traumatic brain injury. Also, an object which enters the skull (bullet or shattered piece of skull), can cause traumatic brain injury.

There is only temporary dysfunction of brain cells when traumatic brain injury is mild. Bruising, torn tissues, bleeding and other physical damage to the brain are more serious traumatic brain injuries that can result into long-term problems or death.


Traumatic brain injury can have can leave a wide range of physical and psychological effects. Some symptoms may appear immediately after the traumatic event, while others may appear days or weeks later.

The symptoms of a mild traumatic brain injury may include:

  • Falling unconsciouss for a few seconds to a few minutes
  • No loss of consciousness, but a state of being dazed, confused or disoriented
  • Headache
  • Nausea or vomiting
  • Fatigue or drowsiness
  • Difficulty sleeping
  • Sleeping more than usual
  • Dizziness or loss of balance
  • Blurred vision, ringing in the ears, a bad taste in the mouth or changes in the ability to smell
  • Sensitivity to light or sound
  • Memory or concentration problems
  • Mood changes or mood swings
  • Feeling depressed or anxious

Moderate to severe traumatic brain injuries can include any of the signs and symptoms of mild, but also:

  • Loss of consciousness from several minutes to hours
  • Persistent headache or headache that worsens
  • Repeated vomiting or nausea
  • Convulsions or seizures
  • Dilation of one or both pupils of the eyes
  • Clear fluids draining from the nose or ears
  • Inability to awaken from sleep
  • Weakness or numbness in fingers and toes
  • Loss of coordination
  • Profound confusion
  • Agitation, combativeness or other unusual behavior
  • Slurred speech
  • Coma and other disorders of consciousness


Traumatic brain injury is caused by a blow or other traumatic injury to the head or body. The degree of damage can depend on several factors, including the nature of the event and the force of impact.

Common events causing traumatic brain injury include the following: falls, vehicle accidents, violence, sports injuries, explosive blasts and combat injuries

Risk Factors

The people most at risk of traumatic brain injury include:

  • Children, especially newborns to 4-year-olds
  • Young adults, especially those between ages 15 and 24
  • Adults age 75 and older


A lot of complications can occur immediately or soon after a traumatic brain injury. Severe injuries increase the risk of a greater number of complications and lead to more  severe problems.


These tips can help reduce the risk of brain injury:

  • Seat belts and airbags.
  • No alcohol and drug use. Don't drive under the influence of alcohol or drugs, including prescription medications that can impair the ability to drive.
  • Helmets. Wear a helmet while riding a bicycle, skateboard, motorcycle, snowmobile or all-terrain vehicle.
  • Prevent falls.
  • Install handrails in bathrooms.
  • Prevent head injuries in children, etc.