Traumatic Brain Injury
A traumatic brain injury (TBI) is the most common cause of death and disability in people. It is a severe and debilitating loss that occurs when the brain is struck or jolted from outside forces.
The Centers for Disease Control and Prevention estimates that 2.6 million emergency room visits, 235,000 hospitalizations and 50,000 deaths occur each year as a result of a traumatic brain injury. The actual incidences of TBI may be even higher because mild TBIs are never seen in the emergency room. As such, TBI represents a substantial source for neuropsychiatric death and disability. Greater than 30% of all car accidents result in TBI. Millions of dollars are necessary to care for these victims over their lifetime.
Traumatic brain injuries are graded as mild, moderate, or severe on the basis of the level of consciousness or Glasgow coma scale (GCS) score. Mild traumatic brain injury is in most cases a concussion and there is normally full neurological recovery, although many of these patients have short-term memory and concentration difficulties. A concussion is caused when the brain receives trauma from an impact or a sudden momentum or movement change. The blood vessels in the brain may stretch and cranial nerves may be damaged. A person may or may not experience a brief loss of consciousness (not exceeding 20 minutes). A person may remain conscious, but feel “dazed” or “punch drunk”.
In moderate traumatic brain injuries the victim can be lethargic and disorganized. In severe injury the patient is comatose, unable to open his or her eyes or follow commands. Patients with severe traumatic brain injury have a significant risk of oxygen loss to their brain and swelling. If these sequelae are not prevented or treated properly, they can exacerbate brain damage and increase the risk of death. Long term effects of a traumatic brain injury can include impaired amnesia, loss of consciousness, depression, confusion, memory loss, headache, dizziness, blurry vision, nausea, vomiting, sensory loss, difficulty speaking, insomnia, and personality changes. The severity of symptoms depends on the extent of the injury. Mild traumatic brain injuries generally present at the time of the injury and are usually temporary. Moderate traumatic brain injuries are similar to those of mild traumatic brain injury but more serious and last longer periods of time. Severe traumatic brain injuries globally affect the person on a permanent basis as a true loss in quality of life.
Given the complexity of the brain and its function, there are a variety of types of injuries that can occur. For example:
- Diffuse Axonal Injury occurs when the brain is shaken or rotated strongly by rotational forces, such as with a car accident. Injury occurs because the unmoving brain lags behind the movement of the skull, causing brain structures to tear. There is extensive tearing of nerve tissue throughout the brain. This can cause brain chemicals to be released, causing additional injury. The tearing of the nerve tissue disrupts the brain’s regular communication and chemical processes. This disturbance in the brain can produce temporary or permanent widespread brain damage, coma, or death.
- Coup-Contrecoup Injury exists when the force impacting the head is not only great enough to cause a contusion at the site of impact, but also is able to move the brain and cause it to slam into the opposite side of the skull, which causes the additional contusion.
- Closed Head Injury happens when a person receives an impact to the head from an outside force, but the skull does not fracture or displace. With a closed head injury, the brain swells and has no place to expand. This can cause an increase in intracranial pressure, which is the pressure within the skull. If the brain swells and has no place to expand, this can cause brain tissues to compress, causing further injury. As the brain swells, it may expand through any available opening in the skull, including the eye sockets. When the brain expands through the eye sockets, it can compress and impair the functions of the eye nerves.
