The defining characteristic of a traumatic brain injury is that it occurs as the result of an external source. For example, while a stroke is an acquired brain injury, it is not traumatic. Traumatic brain injuries (TBI) encompass a wide variety of injuries and syndromes that occur as a result of open or closed head wounds or trauma. Here’s a look at common types of TBI.
Open vs Closed Traumatic Brain Injury
TBI may be an open brain injury or a closed/penetrating brain injury. “Open” refers to TBI that breaks through the skull (such as a bullet or knife) and directly injures the brain tissue. “Closed” TBI are those in which the brain tissue is damaged when the head comes to a rapid stop, something comes to a rapid stop against the head, or as the result of a rapid change in direction (such as whiplash or banging your head into the wall). Alaska Brain Injury Network states that penetrating injuries generally result in more localised damage “result[ing] in discrete and relatively predictable disabilities.”
A concussion is the most common type of brain injury; it may seem like one of the least traumatic of traumatic brain injuries, but it can in fact be a serious and chronic issue. A concussion refers to damage received as the result of a direct blow to the head or a quick change in direction, thus damaging cranial nerves, stretching blood vessels, skull fractures, and swelling or bleeding in the brain.
Immediate symptoms may include loss of consciousness or disorientation. Blood clots may form that can lead to death. There may be no evidence of a concussion on diagnostic imaging tests, and can take weeks or months to fully heal.
Contusion and Hematoma
A contusion is a bruise, which is broken blood vessels as the result of trauma. A contusion in reference to TBI means the brain is bleeding as the result of a direct head wound. Bleeding in the brain is also considered a hematoma. Subdural hematomas can be the result of various types of TBI. Furthermore, a hemorrhage occurs when a blood vessel bursts, leading to massive bleeding.
Symptoms may include headaches, disorientation, dizziness, fatigue, loss of consciousness, nausea, and seizures. Treatment may require surgery.
Diffuse Axonal Injury
Diffuse axonal TBI results from violent shaking or intense rotation, and the damage can be irreversible. Essentially, the head outside moves faster than the brain inside and connecting structures are torn. As a result brain cells can die, which causes swelling in the brain--making the injury even worse.
Shaken baby syndrome is an example of diffuse axonal injury leading to permanent issues. Because babies are so delicate, violent shaking by an adult or older child can cause debilitating and lifelong brain injuries; as such, the act is a serious child abuse crime.
Coup-contrecoup is French for “backlash,” and is an injury so forceful it creates not one but two contusions: one where the trauma actually occurred, and one opposite the site of injury.
Second Impact Syndrome
Also called “recurrent TBI,” second impact syndrome occurs when the patient receives a second injury before the initial injury heals. Because it can take such different ranges of time for different wounds to heal, the “second impact” could be days or months after the first.
While there may be no loss of consciousness, second impacts are more likely to result in swelling, comprehensive brain damage, or death. The Brain Injury Association of America reports that “long-term effects of recurrent traumatic brain injury can be muscle spasms, increased muscle tone, rapidly changing emotions, hallucinations, and difficulty thinking and learning.”