CausesBy Mayo Clinic staff
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. Injury may include one or more of the following factors:
- Damage to brain cells may be limited to the area directly below the point of impact on the skull.
- A severe blow or jolt can cause multiple points of damage because the brain may move back and forth in the skull.
- A severe rotational or spinning jolt can cause the tearing of cellular structures.
- A blast, as from an explosive device, can cause widespread damage.
- An object penetrating the skull can cause severe, irreparable damage to brain cells, blood vessels and protective tissues around the brain.
- Bleeding in or around the brain, swelling, and blood clots can disrupt the oxygen supply to the brain and cause wider damage.
Common events causing traumatic brain injury include the following:
- Falls. Falling out of bed, slipping in the bath, falling down steps, falling from ladders and related falls are the most common cause of traumatic brain injury overall, particularly in older adults and young children.
- Vehicle-related collisions. Collisions involving cars, motorcycles or bicycles — and pedestrians involved in such accidents — are a common cause of traumatic brain injury.
- Violence. About 10 percent of traumatic brain injuries are caused by violence, such as gunshot wounds, domestic violence or child abuse. Shaken baby syndrome is traumatic brain injury caused by the violent shaking of an infant that damages brain cells.
- Sports injuries. Traumatic brain injuries may be caused by injuries from a number of sports, including soccer, boxing, football, baseball, lacrosse, skateboarding, hockey, and other high-impact or extreme sports.
- Explosive blasts and other combat injuries. Explosive blasts are a common cause of traumatic brain injury in active-duty military personnel. Although the mechanism of damage isn't well understood, many researchers believe that the pressure wave passing through the brain significantly disrupts brain function. Traumatic brain injury also results from penetrating wounds, severe blows to the head with shrapnel or debris, and falls or bodily collisions with objects following a blast.
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