Traumatic brain injury (TBI) occurs when a blow to the head causes brain damage. TBI includes anything from mild concussions up to severe brain damage. Treatment can range from rest only to intensive care and emergency surgery. Survivors can face a lifetime of disruptions, physical and mental impairment severe cognitive changes. Most patients will undergo long-term rehabilitation, and some might even need to relearn basic skills.

PRIMARY AND SECONDARY TRAUMATIC BRAIN INJURIES

The primary injury, caused at the moment of impact, can involve a specific part of the brain, or it can affect the entire brain. The skull does not have to be fractured. The impact of the blow to the head might cause the brain to literally crash against the inside of the skull repeatedly as it moves back and forth. The impact can cause bruising, bleeding and tearing of nerve fibers. Directly after the impact, symptoms might be absent. Often though, the condition of the patient can deteriorate very rapidly. At first, the patient might be confused. Memory and vision might be impaired, and dizziness and even unconsciousness might follow. The brain often experiences delayed trauma. Swelling, when it occurs, can push the brain against the skull, and this might reduce the flow of blood and access to oxygen. Injuries resulting from trauma are classified as secondary injuries. The secondary injuries are very often more detrimental than the primary injuries were.

TBI ARE CLASSIFIED INTO THREE MAIN CATEGORIES, DEPENDING ON SEVERITY

Mild TBI (Concussions included) will, if at all, result in only brief loss of consciousness, and the patient will normally be awake – with eyes open. Symptoms might include a headache, disorientation, confusion, and loss of memory.

Moderate TBI will lead to loss of consciousness between twenty minutes and six hours. The patient will be sluggish and inert, but the eyes will open to stimulation. A degree of brain swelling or bleeding will present, and this will lead to sleepiness. But, the patient will be able to wake up when prompted.

Severe TBI leads to unconsciousness for longer than six hours. The eyes will respond to any stimulation and will not open.

PRIMARY INJURIES

Concussion

A concussion is a mild injury to the head that can cause a brief loss of consciousness but does not normally bring about permanent brain injury. A concussion is a diffuse injury, which means it is spread over a large area and cannot be pinpointed to a specific location. Normally a concussion will present as an overall decrease in levels of consciousness.

Contusion

When an impact to the head leaves a bruise to a specific area of the brain. This is also known as coup or counter-coup injuries. In coup injuries, the brain is injured directly under the point of impact while in countercoup injuries the brain it is injured on the opposite side of the impact. Contusions are focal injuries – that is to say, the injury is not spread out (diffuse), but it is specific to a location.

Diffuse Axonal Injury

Axons, which compose what is also known as the white matter of the brain, connect nerve cells throughout the brain. When the brain reverberates (quickly moves back and forth inside the skull), the nerve axons are torn and damaged. During automobile accidents, for example, rapid rotation or deceleration of the brain causes stretching of these nerve cells on a cellular level, the brain’s normal transmission of signals (information) is disrupted, and this can dramatically impact the person’s alertness and wakefulness.

Ischemia is another form of diffuse injury. This happens when certain parts of the brain are cut off from an adequate supply of blood. A marked decrease in blood supply is especially perilous for a TBI patient because the brain becomes extremely sensitive even the smallest decreases in blood supply after a traumatic injury. Changes in blood pressure during the first-week post-head injury can have adverse effects.

Hematoma

When a blood vessel in the brain is ruptured, bleeding starts and the blood naturally clots. Sometimes these hematomas are very small. When a hematoma is large, it might compress the brain. Symptoms will depend on the location of the hematoma and hematomas are named for their location. A hematoma that forms between the skull and the dura (the tough outermost membrane enveloping the brain and spinal cord) is named an epidural hematoma. When the hematoma forms between the brain and the dura, it is named a subdural hematoma. When the hematoma forms deep inside the brain, it is named an intracerebral hematoma. Under fortunate circumstances, the body will reabsorb the hematoma. Large clots (hematomas) are periodically removed by surgery.