A Devastating Impact: The Causes and Effects of Traumatic Brain Injury

by Christina J. Ansted, MPH

Traumatic Brain Injury (TBI)—each of these words alone makes a powerful statement. A traumatic injury is one that causes severe and sometimes irreparable harm. But when such an injury involves the brain, most everyone knows what that means for the injured person and his or her family. Our brain is who we are. It’s how we make our living, how we love, how we hate, how we forgive, and how we interpret the world around us. When that which we rely on so much is compromised, it changes who we are. The effects of traumatic brain injury can be devastating and have far-reaching implications for readjustment to daily living, rehabilitation, and sometimes long-term or indefinite care for injuries too severe for a full recovery.

The number of people with traumatic brain injury is difficult to assess accurately, but is much larger than most people would expect. According to the CDC, there are approximately 1.5 million people in the United States who suffer TBI each year. Of these, 50,000 die and 85,000 suffer long-term disabilities. In the United States, more than 5.3 million people live with disabilities caused by TBI.(1)

Causes and Effects of TBI
The causes of TBI vary widely and are typically due to either a direct impact to the head (i.e., skull or brain) in the form of an open injury where there is penetration of the skull, or closed injury as a result of a rapid deceleration, which causes the brain to collide with the inside of the skull. The top three causes of TBI are vehicle crashes, firearms, and falls. Firearm injuries are often fatal; 9 out of 10 people die from their injuries. Young adults and the elderly are the age groups at highest risk for TBI.(1) But TBI is not exclusive to secondary trauma (i.e., as a result of an outside force on the body). TBI can also be caused by degenerative disease or trauma such as stroke, drug use, and exposure to chemicals, infections (e.g., meningitis or rabies), or lack of, or no oxygen.

Our brains are delicate, and yet most of us are somewhat careless about their protection. There is no cure for TBI—no available “treatment.” Brain cells do not regenerate, although there is some evidence that the brain does add new neurons even after maturity, through a process called neurogenesis.(2) There are no medications to make the damaged areas grow back or heal à la Harry Potter, but recent laboratory and clinical data demonstrate a potentially beneficial role for neurosteroids, such as progesterone and allopregnanolone, in the treatment of traumatic brain injury, ischemic stroke, and some neurodegenerative disorders. Unlike single-target agents, progesterone affects many of the molecular and physiological processes in the cascade of secondary damage after a traumatic brain injury.(3) Therapy and rehabilitation can, of course, also help the brain to compensate and relearn tasks, but efforts are very labor-intensive and results unpredictable.

In the days and weeks immediately following brain injury, the function of surviving brain tissue is often affected by swelling, bleeding, and/or changes in the brain’s complex chemistry. Sometimes blood accumulation must be removed surgically to reduce swelling and pressure within the brain. Controlling swelling and allowing time for the brain’s blood flow and chemical systems to recover usually lead to improved function.(4)

Sometimes TBI is very recognizable or even obvious, as with a victim of a motor vehicle accident. But sometimes, recognizing TBI is not so easy. Take for example veterans of the wars in Iraq and Afghanistan. Soldiers are returning home with cases of mild TBI (mTBI). They are walking, talking, functioning in a daily routine, but are depressed, suffer from headaches, have sensitivity to noise, difficulty with memory or processing thoughts, and perhaps most importantly, they are falling between the cracks of our current healthcare system. Researchers estimate that more than 300,000 U.S. veterans of the wars in Iraq and Afghanistan (20% of the 1.6 million) have sustained a mild traumatic brain injury, also known as concussion, with the majority going untreated.(5) It has been estimated that over 60% of blast injuries result in traumatic brain injury. Because of its frequency relative to that observed in earlier U.S. conflicts, TBI has been labeled the “signature injury” in the Global War on Terror. The prevalence of TBI among OIF (Operation Iraqi Freedom)/OEF (Operation Enduring Freedom) service members is difficult to ascertain, particularly because providers may miss less-severe forms of TBI or mistakenly label other disorders as TBI.(6)

A blast creates a sudden increase in air pressure by heating and accelerating air molecules and, immediately thereafter, a sudden decrease in pressure that produces intense wind. These rapid pressure shifts can injure the brain directly, producing a concussion or contusion. Air emboli can also form in blood vessels and travel to the brain, causing cerebral infarcts. In addition, blast waves and wind can propel fragments, bodies, or even vehicles, causing severe head injuries. Approximately 8% to 25% of persons with blast-related injuries die. Mild TBI (which is usually not associated with visible abnormalities on brain imaging) causes loss of consciousness lasting less than 1 hour or amnesia lasting less than 24 hours. Moderate TBI produces loss of consciousness lasting between 1 and 24 hours or post-traumatic amnesia for 1 to 7 days. Injuries causing loss of consciousness for more than 24 hours or post-traumatic amnesia for more than a week are considered severe. In magnetic resonance images from patients with moderate or severe TBI, punctate hemorrhages may be visible in the corpus callosum or other regions, and there may be other evidence of bleeding or swelling.(7)

The Veterans Administration (VA) and Department of Defense (DOD) have developed clinical practice guidelines for concussion and mild traumatic brain injury. These can be accessed at http://www.healthquality.va.gov/management_of_concussion_mtbi.asp

TBI can be mild, moderate, or severe, but never without consequences. Most commonly, a brain injury can disturb:(4)

• Alertness and concentration
• Self-awareness
• Perception
• Memory and learning
• Reasoning, planning, and problem-solving
• Speech and language
• Motor control
• Emotions

Each of these areas is inextricably linked to who we are and to how we function in our daily lives. Working with TBI patients takes extreme patience. Living with a person who suffered a TBI requires a substantial adjustment, and one that will most likely be everlasting. On the battlefield, protection from TBI comes in the form of helmets or Kevlar, and even that isn’t always enough. At home, however, prevention is everything.

Prevention
What you can do at home
As we already know, the most common cause for TBI is motor vehicle accidents. That can mean a severe car crash or motorcycle accident where the victim did everything right (wore a seatbelt or helmet), but so unnecessarily, the injuries come as a result of carelessness. Don’t let a helmet law, or lack thereof, be the deciding factor for why you don’t wear a helmet. And always wear a seatbelt, even if you are “just going down the street.” If not for yourself, do it for the people who need and love you—the risk clearly outweighs the benefit. The trend for wearing helmets has started to catch on, at least in skiing and snowboarding—two other high-risk sports. In years past, nobody wore a helmet. Now it’s more common to see helmets on the slopes than not, and at some mountains the use of a helmet is required in ski school for children 12 and under.

The second most common reason for TBI is gunshot wounds. The reasons for why a gunshot wound to the head would cause a TBI are obvious, and it’s also obvious that the chances of survival are remote. As we’ve all been told many times, “guns are not toys,” and “guns don’t kill people, people kill people.” Both true. So if you own a firearm, follow safety procedures and never let unskilled individuals or children handle a loaded weapon.

Falls are the third most comment reason for TBI. Everyone falls, trips, or loses their balance. That is pretty hard to prevent 100% of the time, but there are things you can do, such as using a handrail when descending stairs, providing adequate lighting in your home, and keeping your hallways and walkways clear of obstacles.

Research in Clinical Practice—Guidelines for the Management of TBI
Early access to care and time to treatment are pivotal factors in the outcomes of TBI patients. Improved outcomes are associated with time to neurosurgical intervention for those with significant extradural and subdural hemorrhages of less than 4 hours.(8) In pediatrics, the primary goal in treating any pediatric patient with severe TBI is the prevention of secondary insults such as hypotension, hypoxia, and cerebral edema. Despite the publication of guidelines, significant variations in the treatment of severe TBI continue to exist, especially in regards to intracranial pressure (ICP)-guided therapy.(9)

In 1995, The Brain Trauma Foundation came out with Guidelines for the Management of Severe Traumatic Brain Injury, (http://www.braintrauma.org/site/PageServer?pagename=Guidelines). These guidelines were updated in 2000 and have become the accepted guidelines for treatment of TBI the world over. However, there remains disagreement on certain treatments and management of patients with TBI. In 2009, Liao KH, et al. published a study on clinical practice guidelines in severe traumatic brain injury in Taiwan.(10) They organized a severe TBI guidelines committee and selected nine topics, including ER treatment, ICP monitoring, CPP, fluid therapy, use of sedatives, nutrition, intracranial hypertension, seizure prophylaxis, and second-tier therapy. Their work completed the first evidence-based clinical practice guidelines for severe TBIs.(10)

Research has also been conducted on the management of TBI in the intensive care unit (ICU) and reduction of mortality due to TBI. A 2009 publication by Arabi YM, et al. examined the effect of implementing a clinical practice guidelines-based management protocol on the outcome of patients with severe traumatic brain injury. They concluded that the protocol implementation was associated with a reduction in hospital and ICU mortality. This improvement was not associated with an increase in the frequency of tracheostomies and in ICU or hospital length of stay (LOS), suggesting that the improved survival was not associated with the increased number of surviving patients with severe disability and that the functional status might have also improved.(11)

Guidelines for treatment of TBI are critical for healthcare providers on the front lines (e.g., EMS responders). They are often the first medical team to the scene of a TBI and are charged with initiating the prehospital care that can promote a positive outcome. With the knowledge that children and adolescents are most at risk for TBI, EMS Magazine provides an article on evidence-based guidelines for pediatric TBI care available at http://www.emsresponder.com/print/EMS-Magazine/Severe-Pediatric-Traumatic-Brain-Injury/1$10463.

In 2009, Hammell CL and Henning JD published a clinical review in the British Medical Journal on “Prehospital management of severe traumatic brain injury.” Their review provides a summary of points for care:(12)

Summary points

• Management of severe traumatic brain injury is focused on rapid transfer to secondary care while preventing secondary brain injury
• Airway compromise and inadequate ventilation are common and should be addressed immediately
• Prehospital endotracheal intubation should be undertaken with the assistance of anesthetic drugs by appropriately trained physicians
• Hypotension is an independent risk factor for mortality; small boluses of isotonic crystalloid fluids should be given if it occurs
• Patients may be best managed in a neurosurgical centre where they should receive definitive neurosurgical treatment within 4 hours of injury
• There is no role for the routine use of corticosteroids in patients with head injury

Resources
Dealing with TBI is a challenge for both caregivers and patients alike, and there are a number of resources that offer support and guidance. One excellent website is Traumatic Brain Injury.com (www.traumaticbraininjury.com), an exhaustive collective of background on TBI, tips, videos, and even legal help. Another good source of information is available at TBI resources (http://tbiresources.com/caregivers), where recommendations for books, discussion lists, and references are available for download.

Support is also important, if not critical. Families, friends, patients, and caregivers may benefit from support groups and the interaction with others dealing with similar situations. A listing of various support groups can be found at http://www.headinjury.com/linktbisup.htm

The toll of TBI is profound, but through prevention, recognition, and understanding, we can have a positive impact on reducing the severity, and hopefully the prevalence, of TBI.

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References

1. Understanding traumatic brain injury. What are the causes of traumatic brain injury? Available at http://www.traumaticbraininjury.com/content/understandingtbi/causesoftbi.html
2. Howard K. Do brain cells regenerate? Princeton Weekly Bulletin 1999. Available at http://www.princeton.edu/pr/pwb/99/0405/brain.htm
3. Cekia M, Stein DG. Progesterone treatment for brain injury: an update. Future Neurology 2010;5:37-46.
4. Barbara Woodward Lips Patient Education Center. Understanding Brain Injury A Guide for the Family. 2008. Available at http://mayoresearch.mayo.edu/mayo/research/tbims/upload/ubi_families.pdf
5. Hoge CW, Goldberg HM, Castro CA. Care of war veterans with mild traumatic brain injury – flawed perspectives. N Eng J Med 2009;360:1588-1591.
6. Sayer NA, Rettman NA, Carlson KF, Bernardy N, Sigford BJ, Hamblen JL, Friedman MJ. Veterans with history of mild traumatic brain injury and posttraumatic stress disorder: Challenges from provider perspective. JRRD 2009;46:703-716.
7. Okie S. Traumatic Brain Injury in the War Zone. N Eng J Med 2005;352:2043-2047.
8. Kejriwal R, Civil I. Time to definitive care for patients with moderate and severe traumatic brain injury – does a trauma system matter? N Z Med J 2009;122:40-46.
9. Madikians A, Giza CC. Treatment of traumatic brain injury in pediatrics. Curr Treat Options Neurol 2009;11:393-404.
10. Liao KH, Chang CK, Chang HC, Chang KC, Chen CF, et al. Clinical practice guidelines in severe traumatic brain injury in Taiwan. Surg Neurol 2009;72:S66-S73.
11. Arabi YM, Haddad S, Tamim HM, Al-Dawood A, Al-Qahtani S, et al. Mortality reduction after implementing a clinical practice guidelines-based management protocol for severe traumatic brain injury. J Crit Care 2009 [Epub ahead of print].
12. Hammell CL, Henning JD. Prehospital management of severe traumatic brain injury. BMJ 2009;338:b1683.