Concussion Update

By Jennifer Robertson, MD
Attending Physician – Emergency Medicine
Cleveland Clinic

General Info

Concussion is a type of mild traumatic brain injury (TBI) that classically occurs in sports-related incidents but can be due to any traumatic force to the brain (1). The term concussion stems from the Latin word, concussus, which means “to shake violently” (2).  While sport is the most common cause of concussion in children, the most common causes of concussion in adults are falls and motor vehicle accidents (3).  Young children have the highest rate of concussions in all age groups (3).

No worldwide definition of concussion exists (2).  The International Consensus Statement on Concussion in Sport (ICIS) defines concussion as a complex pathophysiological process affecting the brain, induced by biomechanical forces” (4). It may or may not result in loss of consciousness (LOC). The American Academy of Neurology (AAN) defines concussion as having three different grades (5). Grade 1 is transient confusion without LOC. Symptoms and mental status abnormalities on exam resolve in less than 15 minutes. Grade 2 is transient confusion without LOC but symptoms and or mental status abnormalities last more than 15 minutes. Finally, grade 3 includes any LOC, either brief (seconds) or prolonged (minutes).

During the recovery after a concussion, any number of symptoms can result but are usually short-term and resolve spontaneously (4).  If symptoms in at least 3 symptom categories last longer than 1 month, then the “post concussive syndrome” results (6). The symptom categories include physical symptoms such as headache, emotional symptoms such as irritability, concentration or memory problems, insomnia and reduced alcohol tolerance. 

Recap Basics

A concussion is caused by a direct or indirect force to the head leading to strain on the neural and vascular tissue of the brain (7).  Neuronal dysfunction occurs via ionic shifts, changes in axonal transmission, and altered glucose metabolism (7, 8). Early on, glucose metabolism is in overdrive but eventually, mitochondrial dysfunction occurs, leading to decreased oxidative metabolism, axonal injury, and dysfunction of both excitatory and inhibitory neurotransmitters.  Clinical signs and symptoms are most likely due to some of these mechanisms, however, it remains largely unknown how metabolic changes are actually related to symptoms following concussion (8).

Patients can have a wide variety of symptoms following a concussion. Symptoms typically present immediately after injury, but may be delayed several hours (9). There may be headaches, tinnitus, or visual disturbances. Patients may also have difficulty concentrating, develop personality changes, and have sleep disturbances. They may even have motor or sensory symptoms (2, 8). Patients with true concussion may have mild mental status changes, but should otherwise be alert. They should have an unremarkable neurologic exam (9).

Concussion can be difficult to identify as there are no direct objec­tive measures for diagnosis. (9).  In the emergency department (ED), patients should have a full medical assessment, including a history, neurologic, mental status and cognitive exams, and evaluation of gait and balance (4). One very important aspect in evaluating patients is the need for ruling out more serious brain injury.  Per the ICIS, head CT should be obtained if there is evidence of skull fracture, any abnormality on neurologic exam, and/or prolonged or altered level of consciousness (4). Other helpful guidelines to help determine imaging include the Canadian CT head rules (10) and the New Orleans Criteria (11).  Of note, these guidelines are only validated in patients who are aged 16 and older.  In the “what’s new” section, additional guidelines will be discussed as well as assessment in children.

As noted above, patients will need to be imaged and admitted if there are any neurologic abnormalities on exam. If they have a normal neurologic exam, they should be monitored at least 2 hours and then can be safely discharged home with a responsible person (3, 10). In addition, written discharge instructions should be provided. This should include a list of symptoms that should prompt a patient’s return to the hospital, including increasing headache, repeated vomiting, weakness, drowsiness, clear fluid from the nose or ear, hemiplegia, or aphasia (3).

There are no specific treatments for concussion as cognitive and physical rest is the mainstay of therapy (4, 9, 12). Physical rest is straightforward. Patients should avoid strenuous aerobic and resistance activities, including running and weight lifting. Cognitive rest is more difficult but in general, patients should avoid any activity that requires concentration and attention. This includes reading, desk work, video games, and working online (12).  Once patients are completely symptom free at rest, it is recommended that they return to normal activities in a slow, stepwise approach (4, 12). Athletes should not return to play the same day of sus­taining a concussion (4). It is also important for emergency physicians to stress to patients that they must be evaluated by an outpatient physician prior to any return to normal activities.

Patients may ask how long recovery takes. This is difficult to predict as concussion symptoms will vary from person to person (9). In general, the majority of patients’ symptoms resolve within a 7 to 10 day period. However, children and some adults may continue to have symptoms for a longer period of time (4).   Some individuals may have motor, functional, and psychological deficits up to a year, so it is important for patients to have close outpatient follow-up (13, 14, 15). Per the AAN, there is also inadequate data to show that any treatment diminishes long-term symptoms post-concussion (16).

What’s New

In 2013 the AAN updated their guidelines for the evaluation and management of sports concussion in children, adolescents, and adults (16).  These guidelines largely focus on the clinical assessment of concussion. While many are not practical for use in the emergency department, it may be useful information for emergency physicians so that patients can get adequate follow-up, testing, and treatment. A few of the recommended assessment tools include the Graded Symptom Checklist (GSC), the Balance Error Scoring System, and the Sport Concussion Assessment Tool (SCAT). The first two are recommended by  both the AAN (Giza 2013) and the International Consensus in Sport (ICIS). The SCAT was actually developed by the ICIS, which was recently updated to the SCAT3 in 2012 (4).

The GSC, SCAT, and Balance Error Scoring System are all useful for diagnosing early concussion.  However, it is important to note that currently, there is no perfect test that can diagnose concussion in the field (4). The GSC consists of a simple checklist of symptoms and may be administered by any clinician. Evidence indicates that it may identify concussion in athletes involved in any traumatic event (16). The BESS is a tool that takes approximately five minutes to administer. It evaluates for postural stability and is likely to identify concussion with moderate diagnostic accuracy. It may also be helpful to objectively assess motor function on the neurologic exam (4, 16). Finally, the SCAT is a standardized tool that has been recently updated from SCAT and SCAT2 to the SCAT3. It is useful for evaluating athletes aged 13 and older in their initial evaluation. There is a child SCAT3 that can be used in children under the age of 13. The SCAT3 and child SCAT3 may be more useful for emergency clinicians as it can guide the decision whether emergent imaging is needed to exclude more severe brain injury. However, it is important to note that concussion remains a clinical diagnosis. An athlete may have a normal SCAT3 score but still have a concussion (4). Please refer to the article by McCrory et al for a full discussion of this tool.

While there are helpful tools such as the child SCAT3 to guide diagnosis and management of concussion in children, research still remains limited (9).  However, the developing brain does differ physiologically from the adult brain (17,18) and there is likely increase in time to recovery (19, 20). Rodent models have found that following a traumatic brain injury, the immature brain is actually more susceptible than the adult brain to apoptosis (21). Additionally, the pre-frontal cortex is one of the last brain structures to mature. Thus, many young children may sustain attention deficits, hyperactivity, or conduct disorder following a head injury (22). Overall, most authors state that, given the limited research at this time and the physiologic differences in children, a conservative approach should be the rule (4, 9, 17, 23).  A 2012 article by Scorza et al provides excellent guidelines for emergency physicians to refer to regarding the diagnosis and management of concussion in children (9).

Bottom Line/Pearls & Pitfalls

It is important for clinicians to remember that concussion is a clinical diagnosis. Most patients will not require imaging and this should be fully explained to patients. Patients should also be aware that recovery time can vary and that they may be symptomatic for some time.

Finally, it is exceedingly important for emergency physicians to counsel patients regarding the need for close follow-up, and instructions not to resume any activities until cleared in follow-up (12).

Further Reading

  • 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 2013; 47:250–258.
  • Scorza KA, Raleigh MF, O’Connor FG. Current Concepts in Concussion: Evaluation and Management. Am Fam Physician 2012; 85 (2): 123-132.
  • Giza CG, Kutcher JS, Ashwal S, et al.  Summary of Evidence-Based Guideline Update: Evaluation and Management of Concussion in Sports: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology 2013; 80: 2250-2257.

Discussion Questions

  1. How can emergency physicians better educate patients on concussions, the need not to image, and the importance of follow-up?
  2. Would implementing the SCAT3 and child SCAT3 in the emergency department be useful to help guide physicians with their decision-making regarding concussion diagnosis?

References / Further Reading

  1. Laker SR. Epidemiology of Concussion and Mild Traumatic Brain Injury. PM R 2011; 3: S354-S358.
  2. Cantu RC. Overview of Concussion Consensus Statements Since 2000. Neurosurg Focus 2006; 21(4): E3.
  3. Ropper AH, Gorson KC. Concussion. N Engl J Med 2007; 356: 166-72.
  4. 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 2013; 47:250–258
  5. Kelly JP, Rosenberg JH. The Diagnosis and Management of Concussion in Sports. Neurology 1997; 48: 575-580
  6. WHO. The ICD-10 Classification of Mental and Behavioural Disorders.  Diagnostic Criteria for Research.  Geneva, Switzerland:  1993.
  7. Barkhoudarian G, Hovda DA, Giza CC. The Molecular Pathophysiology of Concussive Brain Injury.  Clin Sports Med 2011; 30 (1): 33-48.
  8. Giza CC, Hovda DA. The Neurometabolic Cascade of Concussion. J Athl Train 2001; 36 (3): 228-235.
  9. Scorza KA, Raleigh MF, O’Connor FG. Current Concepts in Concussion: Evaluation and Management. Am Fam Physician 2012; 85 (2): 123-132.
  10. Stiell IG, Clement CM, Rowe BH, et al. Comparison of the Canadian CT Head Rule and the New Orleans Criteria in Patients with Minor Head Injury. JAMA 2005; 294 (12): 1511-8.
  11. Haydel MJ, Preston CA, Mills TJ, et al.  Indications for Computed Tomography in Patients with Minor Head Injury. N Engl J Med. 2000; 343(2):100–5.
  12. Meehan WP. Medical Therapies for Concussion. Clin Sports Med 2011; 30 (1): 115-25.
  13. Carroll LJ, Cassidy JD, Peloso PM. Prognosis for Mild Traumatic Brain Injury: Results of the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury. J Rehabil Med 2004; Suppl 43: 84-105.
  14. Heitger MH, Jones RD, Dalrymple-Alford JC, et al. Motor Deficits and Recovery During the First Year Following Mild Closed Head Injury. Brain Inj 2006; 20 (8): 807-24.
  15. Daneshevar DH, Riley DO, Nowinski, et al. Long Term Consequences: Effects on Normal Development Profile After Concussion.  Phys Med Rehabil Clin N Am 2011; 22(4): 683–700
  16. Giza CG, Kutcher JS, Ashwal S, et al.  Summary of Evidence-Based Guideline Update: Evaluation and Management of Concussion in Sports: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology 2013; 80: 2250-2257.
  17. Guskiewicz KM, McLeod V. Pediatric Sports-Related Concussion. PM R 2011; 3(4): 353-64.
  18. Pullela R, Raber J, Pfankuch T, et al. Traumatic Injury to the Immature Brain Results in Progressive Neuronal Loss, Hyperactivity and Delayed Cognitive Impairments.  Dev Neurosci 2006; 28: 396-409.
  19. Zuckerman SL, Odom M, Lee YM, et al. Sports-Related Concussion and Age: Number of Days to Neurocognitive Baseline. Neurosurg 71 (2): E558.
  20. Field M, Collins MW, Lovell MR, Maroon J. Does Age Play a Role in Recovery from Sports-Related Concussion? A Comparison of High School and Collegiate Athletes. J Pediatr 2003; 142 (5) 546-53.
  21. Bittigau P, Sifringer M, Pohl D, et al. Apoptotic Neurodegeneration Following Trauma is Markedly Enhanced in the Immature Brain.  Ann Neurol 1999; 45(6): 724-35.
  22. Mittenburg W, Wittner MS, Miller LJ. Postconcussion Syndrome Occurs in Children. Neuropsych 1997;11(3):447-52.
  23. Gioia GA, Schneider JC, Vaughan CG, et al. Which Symptom Assessments and Approaches are Uniquely Appropriate for Paediatric Concussion?  Br J Sports Med 2009; 43 (Suppl 1): 3-22.
Edited by Alex Koyfman

3 thoughts on “Concussion Update”

  1. I think one of the questions asked within the ‘discussion questions’ section is a very good one: how can we get doctors to convince their concussion patients to take their follow-up care more seriously? The problem encountered often is a patient’s reluctance to give the injury a second thought. This usually means that they jump right back into whichever activity caused the trauma initially, when a gradual return and better understanding of their condition would greatly benefit the patient.

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