Education

Concussion

concussion There has been a tremendous amount of media coverage on concussions in sports, but few of these sources ever completely answer the basic question: What is a concussion? The American Academy of Neurology defines concussion as a trauma-induced alteration in mental status that may or may not involve loss of consciousness.1 A more recent definition offered by an International Conference on Concussion in Sport2is more precise, but much more complex (see Table). The American Medical Society for Sports Medicine Concussion defines concussion as a traumatically induced transient disturbance of brain function and involves a complex pathophysiological process.3 In basic terms, a concussion occurs when a forceful injury to the brain temporarily impairs brain functioning. Signs and symptoms of concussion It is somewhat easier to understand concussion by the symptoms it causes rather than its definition. The core symptoms of concussion are confusion and memory loss. The symptoms may occur right after the head injury or several minutes later. Confusion may be a blank stare, the inability to pay attention, slowness in responding to questions, disorientation, and slurred speech. In some cases, a person with a concussion will temporarily lose coordination. The amnesia that occurs in a concussion almost always involves memories of the traumatic event. In other words, the sufferer cannot remember what happened to him or her. The memory loss may be more extensive than that, however. The person may not remember important details of the game that occurred before or even after the injury. Aside from these core symptoms, a concussed player may also experience headache, dizziness, feeling disoriented and/or overly emotional. The concussion may also interfere with sleep, causing insomnia. Concussion can also cause problems with concentration and school work making it difficult to return to school or work after a concussion. Concussion versus traumatic brain injury Physicians and scientists tend to disagree about whether or not concussion is different from mild traumatic brain injury. Some people consider traumatic brain injury to be a separate and more permanent phenomenon than concussion. However, most professionals consider concussion to be a form of mild traumatic brain injury. Why is this important? Because symptoms, tests, and treatment recommendations apply to both concussion and mild traumatic brain injury, regardless of which term is used. It also highlights the severity of concussion by calling it what it really is: a traumatic brain injury. Brain changes in concussion The signs and symptoms that occur in concussion fully resolve in 9 out of 10 people within 1 to 2 weeks.4 Thus, for the most part, concussion is viewed as an acute process; there is a problem in the brain that soon goes away. However, there may be subtle, permanent changes that also take place in the brain.5 In the short term, concussion causes something called a post-concussive metabolic cascade. This cascade includes three main abnormalities:

  • Disruption of normal chemical function of brain tissue
  • Impaired energy production in brain cells
  • Altered blood flow to the brain

All of these changes help explain why people undergo behavioral changes and memory loss during a concussion. It also partially explains why people are much more vulnerable to developing a second concussion if they experience head trauma soon after an initial concussion. In other words, if a second injury occurs during this metabolic cascade, the consequences can be more severe and more long-lasting.5

Definitions of Concussion
Fourth International Conference on Concussion in Sport American Medical Society for Sports Medicine
Concussion is a brain injury and is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces. Several common features that incorporate clinical, pathologic and biomechanical injury constructs that may be utilised in defining the nature of a concussive head injury include: 1. Concussion may be caused either by a direct blow to the head, face, neck or elsewhere on the body with an ‘‘impulsive’ force transmitted to the head. 2. Concussion typically results in the rapid onset of short-lived impairment of neurological function that resolves spontaneously. However, in some cases, symptoms and signs may evolve over a number of minutes to hours. 3. Concussion may result in neuropathological changes, but the acute clinical symptomslargely reflect a functional disturbance rather than a structural injury and, as such, no abnormality is seen on standard structural neuroimaging studies. 4. Concussion results in a graded set of clinical symptoms that may or may not involve loss of consciousness. Resolution of the clinical and cognitive symptoms typically follows a sequential course. However, it is important to note that in some cases symptoms may be prolonged. Concussion is defined as a traumatically induced transient disturbance of brain function and involves a complex pathophysiological process. Concussion is a subset of mild traumatic brain injury (MTBI) which is generally self-limited and at the less-severe end of the brain injury spectrum.

On the other hand, research suggests that the structure of brain cells may actually change at the microscopic level after concussion. Concussion can injure an important part of a brain cell called the axon. The axon is what transmits electrical signals along a neuron (brain cell). When axons are damaged, brain cells cannot “fire” appropriately, which means they cannot communicate with one another. This damage may have long-lasting effects on the person who experiences the concussion. Conclusions A concussion is a temporary impairment in brain functioning that is caused by trauma to the head/brain. It causes confusion, headache, and memory loss. Concussion may also cause the sufferer to be disoriented, overly emotional, and have difficulty sleeping. While symptoms usually resolve within 1 to 2 weeks in most people, some changes that take place can be permanent. A single concussion increases a person’s vulnerability to later concussions.   References

  1. Practice parameter: the management of concussion in sports (summary statement). Report of the Quality Standards Subcommittee. Neurology. Mar 1997;48(3):581-585.
  2. McCrory P, Meeuwisse WH, Aubry M, et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. Br J Sports Med. Apr 2013;47(5):250-258.
  3. Harmon KG, Drezner JA, Gammons M, et al. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med. Jan 2013;47(1):15-26.
  4. McCrory P, Johnston K, Meeuwisse W, et al. Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004. Br J Sports Med. Apr 2005;39(4):196-204.
  5. Shrey DW, Griesbach GS, Giza CC. The pathophysiology of concussions in youth. Phys Med Rehabil Clin N Am. Nov 2011;22(4):577-602, vii.

   

assessment

Any athlete who has a suspected concussion should be evaluated by a licensed healthcare professional.1 If your sports organization is fortunate enough to have a medical professional on the sidelines, they will likely perform a complete concussion assessment. That assessment will include a targeted history and physical examination. If a medical professional is not available during play, the player should be removed from the field of play and taken for evaluation.

The medical provider would try to determine the mechanism of injury (e.g., was the injury to the front, back, or the side of the head?).

  • An injury to the front of the brain (frontal lobe) causes irritability and emotionality, like cheerfulness or inappropriate sadness.
  • An injury to the back of the brain (occipital lobe and cerebellum) usually causes dizziness, problems with balance, and visual disturbances.
  • Injuries to the side of the head (parietal lobe) are often associated with headache and nausea

Some helmets include accelerometers that measure the amount of force affecting a player’s head. When players experience forces greater than 100 G (100 times the force of gravity), the likelihood of concussion is increased.2Unfortunatelythis measure is not always a good predictor of whether or not a concussion occurred. In other words, there is “cut off” or minimum threshold force for concussion. Therefore, this measurement is only moderately helpful in sideline concussion management.

The medical professional will then perform a focused physical/neurological examination. The provider will look for signs of dizziness or poor coordination, poor attention, confusion, emotionality, or difficulty following instructions. They may also perform cranial nerve testing (there are 12 cranial nerves that control sensory and motor function in the head and neck). The professional may perform strength and sensation testing and perform tests of balance.

Even after this full assessment, it is not always possible to make an accurate diagnosis of concussion. In borderline cases or in cases where the diagnosis is questionable, neuropsychological testing may be needed (though uncommonly used and essentially never done on the sidelines. Though it is becoming more common in the office and companies are working on apps that might be a tool in diagnosing concussion on the sideline).

When evaluation takes place on the sideline, the medical provider may use one or more concussion screening instruments. There are nearly a dozen different questionnaires that may be used for concussion assessment. These assessments take as little as a minute to up to 10 minutes or more to perform. The more common concussion evaluation tests include:

  • Maddocks Questions
  • Concussion Assessment & Response: Sport Version (CARE)
  • Standardized Assessment of Concussion (SAC)
  • Balance Error Scoring System (BESS) or modified BESS
  • NFL Sideline Concussion Assessment Tool
  • Sport Concussion Assessment Tool 3 (SCAT3)

The final two tools listed are actually combinations of various other tools and assessments. While these tools can be helpful when used appropriately, no single concussion evaluation instrument is perfect. They will not detect all cases of concussion. Likewise, they may indicate a diagnosis of concussion when it actually does not exist. Regardless, it is always best to err on the side of caution. This means preventing the player with suspected or diagnosed concussion from returning to the field of play until symptoms have fully resolved.

 

  1. Harmon KG, Drezner JA, Gammons M, et al. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med. Jan 2013;47(1):15-26.
  2. Broglio SP, Eckner JT, Kutcher JS. Field-based measures of head impacts in high school football athletes. Curr Opin Pediatr. Dec 2012;24(6):702-708.

 

 

 

brain (1)

The first and most important step in managing concussion in an athlete is to prevent that player from returning to the field of play. This means that the player must not participate in a game or in practice for the rest of the day and perhaps longer. Given the competitiveness and drive to win that many players and coaches share, this intervention can be trickier than it sounds. In some cases, it may be necessary to take away a critical piece of equipment to prevent the player from returning to the game.1

The person with a concussion should be watched closely for the first 6 to 8 hours after concussion looking for signs that the symptoms are getting worse. One commonly held misconception— indeed something that used to be recommended in medical circles—was to prevent people with concussion from falling asleep.

Preventing a person with a concussion from sleeping is no longer recommended.1

In fact, it can be helpful to the patient to sleep. On the other hand, if the player is having trouble maintaining consciousness it could suggest a more significant injury and may indicate the need for emergency medical attention (e.g., CT scan of the brain).

Signs of worsening include:

  • Vomits two or more times within four to six hours of the injury
  • If the headache gets significantly worse or becomes “severe”
  • Has a seizure or convulsion (any abnormal or uncontrollable movements)
  • Develops a stiff neck
  • Weakness or numbness in any part of the body

The concussed patient should be made to rest both physically and mentally. This means no telephone, no texting, no music, no television or computer or similar stimulation for a minimum of 8 to 12 hours after concussion. This may also mean time off from school or work. If symptoms persist, the period of rest should be longer. This “neurocognitive” rest is a key component to concussion treatment.2

While a headache is a common symptom of concussion, concussed players should not be given aspirin or non-steroidal anti-inflammatory drugs (NSAIDs). These drugs, such as ibuprofen or naproxen,(at least theoretically) increase the risk of bleeding in the brain. Acetaminophen (Tylenol) does not increase the risk of bleeding and can be used for headache and concussion.1

Several other types of drugs and substances should be avoided in people with concussion. These include opioids (e.g., morphine), muscle relaxants, benzodiazepines (e.g., Ativan, Valium), and alcohol. These substances tend to impair cognitive performance and even consciousness and can make it difficult to monitor progress in someone with a concussion. Even though sleep disturbances are quite common in people with concussions, the general recommendation is that they should avoid stimulant or sleep-inducing medications shortly after the concussion occurs. A physician may manage sleep disturbances with medication, however.

There is some evidence to suggest that omega-3 fatty acids may be helpful in reducing the damage that occurs during mild traumatic brain injury/concussion.3,4,5,6 Omega-3 fatty acids, such aseicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are found in fish oils and as dietary supplements.

If symptoms of anxiety or depression emerge as a consequence of concussion, the symptoms should be treated by a professional. Treatment may include psychological therapy (i.e., talk therapy) or pharmacological therapy (i.e., medications).7

 

References

 

  1. Harmon KG, Drezner JA, Gammons M, et al. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med. Jan 2013;47(1):15-26.
  2. McCrory P, Meeuwisse WH, Aubry M, et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. Br J Sports Med. Apr 2013;47(5):250-258.
  3. Mills JD, Bailes JE, Sedney CL, Hutchins H, Sears B. Omega-3 fatty acid supplementation and reduction of traumatic axonal injury in a rodent head injury model. Journal of Neurosurgery. 2011;114(1):77-84.
  4. Tyagi E, Agrawal R, Zhuang Y, Abad C, Waschek JA, Gomez-Pinilla F. Vulnerability imposed by diet and brain trauma for anxiety-like phenotype: implications for post-traumatic stress disorders. PLoS One. 2013;8(3):e57945.
  5. Wu A, Ying Z, Gomez-Pinilla F. Dietary omega-3 fatty acids normalize BDNF levels, reduce oxidative damage, and counteract learning disability after traumatic brain injury in rats. Journal of neurotrauma. 2004;21(10):1457-1467.
  6. Wu A, Ying Z, Gomez-Pinilla F. Omega-3 fatty acids supplementation restores mechanisms that maintain brain homeostasis in traumatic brain injury. Journal of neurotrauma. 2007;24(10):1587-1595.
  7. Bloom GA, Horton AS, McCrory P, Johnston KM. Sport psychology and concussion: new impacts to explore. Br J Sports Med. Oct 2004;38(5):519-521.

 

omega 3 There are very few treatments for concussion beyond rest and symptom management. Other than acetaminophen for headaches, there are no drugs formally recommended for the treatment of concussion.1,2 Nevertheless, several medications and supplements are currently being tested for their potential usefulness in concussion. Among these, omega-3 fatty acids are among the most intriguing. Various animal studies suggest that omega-3 fatty acids could be helpful in reducing the effects of concussion on the brain. In fact, clinical trials are currently underway that will help determine whether omega-3 fatty acids play a role in the treatment of concussion.   Omega-3 fatty acids Omega-3 fatty acids are polyunsaturated fats with a very particular chemical structure. The “three” in omega-3 means that there is a double bond on the third carbon atom from the end. More importantly, omega-3 fatty acids have a number of important effects on health including roles in cancer, inflammation, and cardiovascular disease.3,4Three of the more important omega-3 fatty acids are linoleic acid, docosahexanoic acid (DHA), and eicosapentaenoic acid (EPA). Omega-3 fatty acids are found in fish oils, eggs, and certain plant oils, such as flaxseed oil. They are also available in supplement form. Omega-3 fatty acids and brain trauma Omega-3 fatty acids, especially DHA, are very important for brain cell structure and function.5 DHA improves brain cell function by reducing oxidative stress and inflammation. It also supports the cell membrane of brain cells, particularly at the synapse.6 The body can produce DHA to a very limited extent, but most DHA and other omega-3 fatty acids enter the body through the diet. If someone does not consume enough omega-3 fatty acids, this could lead to neurological dysfunction.6 Omega-3 fatty acid supplementation Much of what we know about omega-3 fatty acids and concussion has come from studies in animals. When animals are subjected to brain trauma, it creates characteristic changes in the brain and affects behavior. Researchers use experimental trauma to study ways to improve function after injury or to minimize the effects of the trauma. In one series of experiments, researchers fed one group of rats a DHA dietary supplement while another group simply ate a normal diet. After four weeks, both groups suffered an experimental brain injury. The rats that received DHA experienced fewer trauma-related changes in the brain than rats fed a normal diet.7Rats given DHA performed better on tests of learning and memory than animals without supplementation.

In other words, DHA supplementation at least partially protected rats from the effects of traumatic brain injury.7

Other researchers showed that EPA and DHA given after mild brain injury reduced concussion damage in the brain at the microscopic level.8,9 Specifically, DHA was able to reduce the levels of APP in axons, which is a marker of brain trauma. Omega-3 fatty acid deficiency Conversely, when mice were deprived of DHA, they did worse on behavioral tests and had larger brain lesions after traumatic brain injury compared to mice fed a normal diet.10 Thus, DHA deficiency can increase the damage caused by brain trauma, at least in mice. Omega-3 fatty acid studies in humans Despite the relatively low cost and wide availability of omega-3 fatty acids, few human studies have directly examined the effects of omega-3 fatty acids in the treatment of concussion or mild traumatic brain injury. While clinical trials are ongoing, we still do not know what effect, if any, that EPA or DHA will have in humans with concussion. So far, the evidence in humans is limited but promising. For example, physicians published a case study in which a person with severe traumatic brain injury (much worse than concussion) was given large amounts of omega-3 fatty acids (EPA and DHA) and seemed to do well without any adverse events from the supplements.11 Unfortunately, it is still too early to say definitively whether omega-3 fatty acids are protective or useful in treating concussion; however, clinical trials will hopefully shed light on this intriguing possibility.

  1. Harmon KG, Drezner JA, Gammons M, et al. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med. Jan 2013;47(1):15-26.
  2. McCrory P, Meeuwisse WH, Aubry M, et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. Br J Sports Med. Apr 2013;47(5):250-258.
  3. Harris WS, Dayspring TD, Moran TJ. Omega-3 fatty acids and cardiovascular disease: new developments and applications. Postgrad Med. Nov 2013;125(6):100-113.
  4. Laviano A, Rianda S, Molfino A, Rossi Fanelli F. Omega-3 fatty acids in cancer. Curr Opin Clin Nutr Metab Care. Mar 2013;16(2):156-161.
  5. Gomez-Pinilla F. Brain foods: the effects of nutrients on brain function. Nat Rev Neurosci. Jul 2008;9(7):568-578.
  6. Gomez-Pinilla F. The combined effects of exercise and foods in preventing neurological and cognitive disorders. Prev Med. Jun 2011;52 Suppl 1:S75-80.
  7. Wu A, Ying Z, Gomez-Pinilla F. Dietary omega-3 fatty acids normalize BDNF levels, reduce oxidative damage, and counteract learning disability after traumatic brain injury in rats. J Neurotrauma. Oct 2004;21(10):1457-1467.
  8. Mills JD, Bailes JE, Sedney CL, Hutchins H, Sears B. Omega-3 fatty acid supplementation and reduction of traumatic axonal injury in a rodent head injury model. J Neurosurg. Jan 2011;114(1):77-84.
  9. Bailes JE, Mills JD. Docosahexaenoic acid reduces traumatic axonal injury in a rodent head injury model. J Neurotrauma. Sep 2010;27(9):1617-1624.
  10. Desai A, Kevala K, Kim HY. Depletion of brain docosahexaenoic Acid impairs recovery from traumatic brain injury. PLoS One. 2014;9(1):e86472.
  11. Lewis M, Ghassemi P, Hibbeln J. Therapeutic use of omega-3 fatty acids in severe head trauma. Am J Emerg Med. Jan 2013;31(1):273 e275-278.

  What is Concussion Concussion Assessment Concussion Treatment Concussion Treatment: A Focus on Omega-3 Fatty Acids

About Dr. Dalhgren

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Dr. Andrew Dahlgren (Drew) is a Sports Medicine physician practicing in Richmond, Virginia. He is married to his wonderful partner, Amy, and has four amazing children. Learn more about Dr. Drew and his practice philosophy.

The internet allows me to spend the time educating you on the various topics that will help you maintain or improve your health.

Education should be the beginning of your journey back to health. It is a continuous process where each day you learn new things about yourself, your body and your environment. Join me as we both learn and try to improve our health and well being.

Dr. Dahlgren is a Sports Medicine physician practicing in Richmond, Virginia. He works with OrthoVirginia, a large orthopaedic group with offices throughout Virginia.

Dr. Dahlgren’s office is located on the campus of Memorial Regional Medical Center, part of the Bon Secours Richmond Health System. His office address is 8200 Meadowbridge Rd, Suite 200, Mechanicsville VA 23116.

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