A Two-Part Series On Traumatic Brain Injuries (Part 1)
What is Traumatic Brain Injury?
Traumatic Brain Injury (TBI) is a collective term that describes the wide range of pathologic conditions and types of trauma involving the brain. The Centers of Disease Control and Prevention or CDC estimates that around 1.7 million people suffer from TBI each year, of the reported cases, around 52,000 die and 275,000 are hospitalized. TBIs are among the leading causes of trauma death in the US, with at least 30.5% of injury-related deaths associated to it. Not only are TBIs lethal, they are also associated with severe disabilities with long-term deficits and effects.
The understanding of the causes, types of injuries and its effects on the brain, as well as the immediate recognition of signs and symptoms, are crucial in the management of people who suffered brain trauma. Having basic knowledge of brain injuries and its mechanisms can help a lot in the proper care of patients.
Causes of Brain Injury
A TBI is caused by a generated force to the head such as blows, bumps or jolts causing trauma to the delicate neural tissues beneath the cranial vault. These contributory factors are frequently associated with road crashes, violence, falls, and risky sports. However, not all traumas to head lead to a TBI. Depending on the force applied to the head, the severity of the effect to brain can range from mild (brief change in consciousness or mental status) to severe (loss of conscious for an extended period or loss of memory/amnesia after the injury).
Types of Traumatic Brain Injuries
There are two broad classifications of TBIs: penetrating injuries and closed head injuries.
Penetrating Injuries involve foreign objects (e.g. sharp objects, a bullet) that enter the skull causing damage in specific parts of the brain. These injuries can lead to localized or generalized damage to the brain. Symptoms and effects of the injuries vary depending on which part of the brain is affected.
Closed Head Injuries occur when the head suffers direct impact or blow, such as, in motor vehicle crashes. The resulting brain damage are further classified as: concussion, contusion, skull fractures, hematoma, and diffuse axonal injury.
- Concussion is the most common type of TBIs that is reported each year. It results from blunt trauma to the head due to fall or blow to the head. The direct injury to the brain causes it to momentarily stop functioning. While concussions are generally mild, with patients completely recovering after a few seconds or minutes, it may have underlying serious effects that become apparent only days after the injury.
- Contusion occurs when the head directly bumps with a rigid object. The causes of contusions are the same with concussion but are usually more severe. The forceful impact results in the rapid shifting of the brain and ‘bouncing’ from one side of the skull to the other. The damage can either be localized to the site of impact (coup injury) or in two different sides (coup-contrecoup injury).
- Skull fractures occur when the bony skull breaks due to forceful impact. These injuries can cause mild-to-severe brain injury depending on the type and location of fracture. People who suffered skull fracture require close medical supervision.
- Intracranial hematomas (epidural, subdural and intracerebral hematoma) develop when the head injury causes a blood vessel to rupture inside the cranial vault. Intracranial hematomas, regardless of its type, require emergency medical attention. Hematomas often cause an abrupt deterioration of brain functions.
- Diffuse Axonal Injury is characterized by the extensive damage of a wide area of the brain, usually involving the cerebrum and the brain-stem This TBI is often caused by car crashes or events involving mechanical sheering forces. Majority of patients who sustain this brain trauma end up in coma or suffer long-term neural deficits.
Closed head injuries can also cause secondary brain damage, such as brain swelling, epilepsy, hematoma, intracranial infection, cognitive problems, etc., that evolves long after the trauma.