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Traumatic brain injury (TBI) can affect anyone at any age. Males aged 15 to 24 are vulnerable due to their tendency towards a high-risk lifestyle. Young children and people over 75 years old are susceptible to head injuries caused by falling. Violent shaking of an infant can also cause brain injury. Half of all TBI's in the United States are caused by accidents involving automobiles, motorcycles, bicycles and pedestrians¹. Alarmingly, fifty percent of TBI incidents involve the use of alcohol². The incidence rate of traumatic brain injury is estimated to be between 150-250 cases per 100,000 people per year in both industrialized and non-industrialized countries³. In the U.S., approximately 1.4 million people suffer from TBI annually and approximately 50,000 die from head injury⁴.

Traumatic brain injury occurs when sudden trauma causes damage to the brain⁵. It can result from a closed head injury, such as when the head suddenly and violently hits an object, or a penetrating head injury, when an object pierces the skull and enters brain tissue. The damage can be focal (limited to one area of the brain) or diffuse (involve more than one area of the brain). Depending on the extent of damage, the symptoms can be mild, moderate or severe. There are several types of TBI's⁶:

• Concussion: short loss of consciousness due to a head injury
• Depressed skull fracture: pieces of the broken skull press into brain tissue
• Penetrating skull fracture: something such as a bullet pierces the skull
• Contusion: a distinct area of swollen brain tissue mixed with blood released from broken blood vessels; can also occur in response to shaking of the brain within the confines of the skull (e.g., shaken baby syndrome)
• Diffuse axonal injury or shearing: damage to individual neurons and loss of connections among neurons
• Hematoma: heavy bleeding into or around the brain
  • Epidural hematoma: bleeding between the skull and the dura (one of the three membranes that covers the brain)
  • Subdural hematoma: bleeding between the dura and the arachnoid membrane (one of the three membranes that covers the brain)
  • Intracerebral hematoma ? bleeding within the brain itself

Since little can be done to reverse the initial brain damage caused by trauma, initial medical care focuses on stabilizing the patient, preventing further injury and ensuring proper oxygen supply to the brain and the rest of the body. Many TBI patients may also have spinal cord injuries so great care must be taken in moving and transporting them.

After the patient has been stabilized, medical personnel assess his or her condition by measuring vital signs and reflexes, and by performing a neurological examination. The patient's level of consciousness and neurological functioning is assessed using the Glasgow Coma Scale (GCS), a standardized 15-point test that uses eye opening, best verbal response and best motor response to determine the severity of the brain injury⁷. In addition, imaging tests such as x-rays, CT scans and MRI's are used to determine the diagnosis and prognosis.

Approximately fifty percent of TBI patients require surgery to remove or repair hematomas or contusions⁸. Serious head injuries may result in⁹:

• Stupor: patient is unresponsive and can be aroused briefly by a strong stimulus such as sharp pain
• Coma: patient is totally unconscious, unresponsive, unaware and unarousable, and does not have sleep-wake cycles; length is generally a few days to a few weeks
• Vegetative state: patient is unconscious and unaware, but continues to have sleep-wake cycles and periods of alertness
• Persistent vegetative state (PVS): patient is in a vegetative state for more than thirty days; upper portions of the brain are damaged but the lower portions are spared
• Locked-in syndrome: patient is aware and awake but cannot move or communicate due to complete paralysis of the body; lower portions of the brain and the brainstem are damaged but the upper brain is not damaged

Disabilities caused by TBI depend on the severity of the injury as well as the age and general health of the patient. Some common disabilities include problems with cognition, sensory processing, communication, behavior and mental health. Part two of this article will address post-injury complications, long-term disabilities, treatment and prevention.

Discussion questions

1. Please summarize the article. What is the main point of the article?
2. What is a traumatic brain injury?
3. What are the main causes of TBI's?
4. What are the various types of TBI's?
5. What is the Glasgow Coma Score?
6. How is a patient treated immediately after a TBI?
7. What are the potential results of a TBI?

References:

1. Traumatic Brain Injury: Hope through Research. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health. (Accessed November 15, 2007)
2. Traumatic Brain Injury: Hope through Research. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health. (Accessed November 15, 2007)
3. Leon-Carrion J, Dominguez-Morales M, Barroso y Martin, Murillo-Cabezas F. Epidemiology of Traumatic Brain Injury and Subarachnoid Hemorrhage. Pituitary. Volume 8, Numbers 3-4 / December, 2005. (Accessed November 15, 2007)
4. Traumatic Brain Injury: Hope through Research. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health. (Accessed November 15, 2007)
5. NINDS Traumatic Brain Injury Information Page. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health. (Accessed November 15, 2007)
6. Traumatic Brain Injury: Hope through Research. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health. (Accessed November 15, 2007)
7. Traumatic Brain Injury: Hope through Research. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health. (Accessed November 15, 2007)
8. NINDS Traumatic Brain Injury Information Page. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health. (Accessed November 15, 2007)
9. NINDS Traumatic Brain Injury Information Page. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health. (Accessed November 15, 2007) and Traumatic Brain Injury: Hope through Research. National Institute of Neurological Disorders and Stroke. U.S. National Institutes of Health.

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