TBI is an injury to the brain from some type of trauma or force, such as a bump or blow to the head or an object such as a bullet entering the skull. TBI can cause problems with brain function. Some TBIs result in mild, temporary problems. A more severe TBI can lead to serious physical, mental, and emotional symptoms; coma; and even death.1 People or children who have already experienced brain injury or brain disease are at higher risk for developing TBI.
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TBI includes (but is not limited to) several types of injury to the brain:
- Skull fracture occurs when the skull cracks. Pieces of broken bone from the skull may cut into the brain and injure it, or an object such as a bullet may pierce the skull and enter the brain.
- Contusion is a bruise of the brain, where swollen brain tissue combines with blood released from broken blood vessels to increase pressure on the brain. A contusion can occur from the brain shaking back and forth against the skull, such as from a car crash or sports injury or in shaken baby syndrome.
- Intracranial hematoma occurs when a major blood vessel in or around the brain is damaged and begins bleeding. The pooling of blood puts pressure on the brain.1,2
Concussion is among the most common forms of TBI.1 A concussion can happen when the head or body is moved back and forth quickly, such as during a car crash or sports injury, or from a blow to the head. Concussions are often called “mild TBIs,” because they are usually not life-threatening. However, they still can cause serious problems, especially if the person has experienced a concussion before.3,4
People may also experience non-traumatic brain injuries that result from a problem, such as a stroke, infection, or broken blood vessel, inside the brain or skull. A person who has a non-traumatic brain injury may have some of the same symptoms as a person who has a TBI. Both traumatic and non-traumatic brain injuries can have serious, long-term effects on a person’s ability to think and function.5,6
TBI can happen to anyone, but some people are more likely to experience a TBI than others. For example, according to the Centers for Disease Control and Prevention (CDC),1 young children, teenagers, and adults age 65 or older are at higher risk for TBI. CDC statistics1 also show that males are at higher risk than females in most age groups.
In addition, members of the military—both those in combat and those in reserves—are at higher risk for TBI than people who are not in the military.7 For instance, many military personnel in Iraq and Afghanistan have been exposed to TBI hazards, such as improvised explosive devices. TBIs from blasts and explosives have features that are distinct from features of non–blast-related injuries. Blast-related TBIs can include damage from waves of intense pressure, sometimes called blast or shock waves, and from high-temperature winds of an explosion, as well as contact with physical objects and penetrating pieces of shrapnel.8 NICHD works with the U.S. Department of Defense on TBI research. For more information about TBI in the military, visit the Defense and Veterans Brain Injury Center website.