One of the most devastating types of traumatic brain injury is also, unfortunately, one of the most common. Its name is diffuse axonal injury and it can result from motor vehicle accidents.
DAI is serious for a number of reasons. The prognosis for recovery often is not good, treatment options are often limited and diagnosis can be difficult.
Causes
The axons are long connecting nerve fibers in the brain. Rapid acceleration and deceleration, such as may occur in an auto accident, can cause the brain to quickly move backwards and forwards within the skull. This forceful motion can cause the axons to tear, which can cause damage to many different brain areas at the same time.
Symptoms
DAI typically causes victims to lose consciousness. This can last six hours or more. It is not unusual for the patient to slip into a coma. In a mild case of DAI, however, the patient may remain conscious. However, he or she will likely demonstrate other symptoms indicative of brain damage. These may include difficulty sleeping or, conversely, fatigue/drowsiness. Other possible symptoms include the following:
- Dizziness/loss of balance
- Confusion/disorientation
- Nausea/vomiting
- Headache
Because the specific damage to the brain determines what sort of symptoms develop, they can vary greatly.
Diagnosis
Diagnosing traumatic brain injury usually involves imaging studies of the brain, such as CT or MRI. However, these techniques may not be effective at diagnosing diffuse axonal injury because the damage it causes can be microscopic and therefore difficult to visualize even with the most powerful and sophisticated imaging available.
Treatment
Doctors cannot perform surgery to correct the damage that DAI causes. In the short term, treatment may consist of a course of steroids to reverse any swelling in the brain and reduce the chance of further damage. In the long term, a rehabilitation program involving counseling, adaptive equipment training, speech therapy, physical therapy, etc. may produce results for the patient with mild to moderate DAI. However, patients with severe DAI may not survive at all. If they do survive, they may enter a vegetative state.