Traumatic brain injury (TBI) occurs when a sudden physical assault on the head, such as a bump, blow, jolt or wound that breaks through the skull, causes damage to the brain that disrupts normal functioning. The damage can cause bruising, swelling or tearing of brain tissue and may be focal, confined to one area of the brain, or diffuse, involving more than one area. Not every blow to the head results in a TBI, and the severity of those that do may range from mild, which might be a brief change in mental status or consciousness, to severe, which could include an extended period of unconsciousness or memory loss.
Most people fully recover from a mild brain injury, requiring only a sufficient period of rest. More severe or repeated trauma to the brain can have long lasting consequences, including periods of unconsciousness, loss of memory, disability, coma and even death. Several types of injury can result from a TBI, such as:
- Skull fracture – this is when the bone of the skull cracks or breaks
- Contusion – this comes from pieces of the broken skull pressing into the brain causing bruising of the tissue or when the brain is shaken and makes violent contact against the inside of the skull
- Hematoma – damage to a major blood vessel resulting in heavy bleeding into or around the brain
- Coma – deep state of unconsciousness
Symptoms of a Traumatic Brain Injury
Symptoms of a TBI may be immediate or may not appear until days or even weeks following the injury. For a head injury to be classified as a traumatic brain injury, there does not have to be evidence of a concussion. When there is a concussion, this is often the mildest type of TBI, resulting in a headache or neck pain, nausea, ringing in the ears, dizziness, and tiredness that diminish and go away with rest. Those suffering a moderate or severe TBI may have those symptoms, plus others, including:
- Headaches that get worse or do not go away
- Repeated vomiting or nausea
- Convulsions or seizures
- Inability to awaken from sleep
- Slurred speech
- Weakness or numbness in the arms and legs
- Dilated eye pupils
Common Causes of Traumatic Brain Injuries
- Falls – the leading cause of TBIs are falls, which include a wide range of types — falling out of bed, slipping in the bath, tumbling down steps, falling off ladders and other similar activities. These most often happen with young children and older adults.
- Vehicle-related collisions – collisions involving cars, motorcycles or bicycles, whether as a passenger or a pedestrian struck by a vehicle, are the second most common cause of traumatic brain injury.
- Violence – roughly 20 percent of all traumatic brain injuries result from some act of violence, like gunshot wounds, domestic violence or child abuse. Shaken baby syndrome, caused by the violent shaking of an infant, is a traumatic brain injury that often results in the death of the baby.
- Sports injuries – the high rate of chronic traumatic encephalopathy (CTE), a progressive degenerative disorder of the brain, that has been found in football players with a history of repetitive brain trauma has been receiving a lot of media attention, but it is not the only sport where TBI is common. Traumatic brain injuries may be caused by injuries from a number of high-impact sports, including soccer, boxing, baseball, lacrosse, skateboarding, hockey, and others.
- Military service – explosive blasts from IEDs, as well as other combat injuries are a common cause of traumatic brain injury in active-duty military personnel.
Treatment and recovery will depend on the severity of the injury. TBI can cause a wide range of changes, physically, mentally and emotionally and can be associated with post-traumatic stress disorder (PTSD). Individuals with more significant injuries usually need rehabilitation.