Concussion

By admin On Nov 20, 2023

Ovid: 5-Minute Sports Medicine Consult, The

Concussion

Daryl A. Rosenbaum

Anna G. Monroe

Basics

Description

“Concussion is defined as a complex pathophysiologic process affecting the brain, induced by traumatic biomechanical forces” (1).
Common features include the following:
- The blow may be directly to the head, face, or neck, or the force may be transmitted indirectly after a blow elsewhere on the body.
- Neurologic signs and symptoms present quickly and disappear spontaneously, although in a small number of cases the symptoms may be prolonged.
- Symptoms result from a functional disturbance in the absence of structural pathology, and imaging studies are usually normal.
- Concussion symptoms may or may not include loss of consciousness (LOC).
Synonym(s): “Bell ringer”; “Ding”; Mild traumatic brain injury (TBI); Minor head trauma; Commotio cerebri

Epidemiology

207,830 ED visits for nonfatal sports-related traumatic brain injuries per year between 2001 and 2005 (2)
Children ages 5–18 yrs represented 65% of those ED visits (2).
Estimated 1.6–3.8 million sports-associated traumatic brain injuries (2)
Incidence likely higher because athletes, coaches, or medical providers may fail to recognize the signs and symptoms of a concussion or athletes try to minimize the symptoms in order to continue to play (3,4).
In a study of high school football players, only 47.3% reported their concussion. 2/3 withheld information because they did not think their symptoms needed medical care. Almost 1/2 wanted to avoid being withheld from play, and a little more than 1/3 simply lacked understanding of concussion (5).
Possible underreporting of concussion especially in children because many do not seek medical care (4)
Some evidence of a higher incidence of concussion in female high school and college athletes even when comparing the same sports; the reason is unclear but could be due to more honest reporting of concussion in females (4,6).
572 concussions per year for college athletes between 1988 and 2004 (7)
54.8% of the total concussions during that period of time occurred in football (7).
Women's soccer, men's ice hockey, men's soccer, and women's basketball each represented between 5% and 7% of total college concussions for the same time period (7).

Risk Factors

Participation in contact and collision sports (2,3,4,7)
An athlete with a previous concussion may be more likely to have a repeat concussion than an athlete without a history of a concussion (3).
Improper technique (eg, leading with the head, or “spearing,” in football) (7)

Genetics

Investigations ongoing as to the significance of apolipoprotein (Apo) E4, ApoE promoter gene, tau polymerase, and others in concussion (1,8)

General Prevention

Evidence does not support prevention of concussion in football or rugby with current helmet technology, but helmets do prevent skull fractures and other head injuries. Likewise, while mouth guards do not prevent concussion, they do decrease dental and orofacial injuries (1,4,9).
Rules that promote safe and proper techniques (eg, outlawing “spearing” in football, leading with the head, and head-to-head contact) should be coached and enforced to limit concussion (1,7,10).
Encourage fair competition but discourage violent behavior in sports, especially among young athletes (1).

Etiology

Complicated pathophysiology that is incompletely understood (1,4,8)
Impact and resulting forces create shear injury to vessels and neurons (4,8).
Biochemical chain reactions are set in place, some of which may involve the release of excitatory amino acids (4,8,10).
Resulting decrease in cerebral metabolism occurs (4,8,10).
Alternatively, the blow may create immediate neuronal depolarization followed by a refractory period where neural transmission does not happen (8).

Diagnosis

Historically, numerous classification systems for grading severity have existed (4).
Systems were based mainly on the presence of LOC and/or amnesia (4).
More recent consensus statements recommend against concussion grading systems (1,10,11,12)[C].
Judge treatment for and severity of concussion on an individual basis according to the burden, nature, and duration of symptoms.
The presence of certain “modifiers” also may indicate the need for a more detailed workup or different management strategies (1)[C].
Modifiers include the following: Number, duration, or severity of symptoms; LOC for more than a minute; amnesia; concussive convulsions; frequent concussions or those occurring in close proximity; sustaining subsequent concussions with less impact; concussions in those <18 yrs of age; the presence of other comorbid or premorbid conditions such as mental health or learning disorders, including attention deficit hyperactivity disorder (ADHD); taking psychoactive drugs or anticoagulants; having a dangerous style of play; or participating in high-risk activities (1)[C].

Pre Hospital

Address airway, breathing, and circulation (ABCs) (4)[C].
Consider cervical spine (C-spine) immobilization (all unconscious athletes should have C-spine immobilization) (4)[C].
Do not remove the helmet in football or ice hockey players if C-spine injury is suspected (13)[C].
Assess level of consciousness with the Glasgow coma scale (GCS) (13)[C].
Evaluate for other trauma such as skull fractures (including basilar skull fractures) or lacerations (13)[C].
Perform a neurologic exam including cognitive evaluation and balance assessment (13)[C].
Conscious athletes in whom C-spine trauma is not suspected may exit the field and undergo a more thorough exam (13)[C].
Immediately transfer athletes with prolonged LOC, focal neurologic deficits including asymmetric pupils and declining GCS or worsening symptoms, athletes with comorbidities (eg, hemophiliacs), and those with persistent vomiting (3)[C].

History

Direct blow to the head, sudden rotational or acceleration-deceleration force to the head in the absence of direct trauma, or transmitted force to head (13)
Athletes often fail to recognize or report their symptoms. Concussion should be considered in anyone demonstrating signs of a concussion (4).
Standardized symptom checklists such as the one found in the Sport Concussion Assessment Tool 2 (SCAT 2) that allow the athlete to score his or her complaints on a scale of 0–6 may be useful when evaluating the concussed athlete (1)[C].
Athletes may complain of any of the following: headache (HA) or neck pain; feeling off-balance or dizzy; nausea or vomiting; problems with vision or hearing including ringing in the ears; confusion; slowness, fatigue, or sleepiness; irritability or other emotional problems; concentration difficulty; memory problems; “dinged”; “dazed”; or “don't feel right” (3)[B].
Prospectively validated symptoms include HA, dizziness, blurred vision, attention deficit, memory problems, and nausea (3)[A].

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Physical Exam

Physical signs: LOC, amnesia, or balance problems (1,3)[A]
Behavioral changes such as irritability (1,3)[B]
Cognitive problems such as slowed reaction times (1,3)[B]
Sleep disturbances such as drowsiness (1,3)[B]
After addressing emergency medical issues, formal concussion assessment should occur (1)[C].
Perform a detailed neurologic exam including cognitive evaluation and balance assessment (13)[C].
Consider administering the SCAT 2 or other standardized test (1)[C].
The SCAT 2 was developed by the 3rd International Conference on Concussion in Sport and incorporates 2 prospectively validated tests, the Maddocks Score and the Standardized Assessment of Concussion (SAC), into a comprehensive tool (1,3).
The SCAT 2 contains 8 sections and assesses the following domains: Subjective rating of symptoms; physical signs; GCS; Maddocks score (which assesses recent memory about the game but is not used in the final score); cognitive testing such as orientation, immediate memory, and concentration; balance examination using the modified Balance Error Scoring System (BESS); coordination test (finger to nose); and repeated cognitive testing focusing on delayed memory (1).
An overall score is calculated out of 100 possible points (1).
Cut-off scores are not currently known, and the test has not yet been validated (1).
Score is useful with repeat testing or with known baseline (1)[C].
The SCAT 2 should not be used as the only tool to diagnose concussions, determine whether recovery has occurred, or decide when to allow an athlete to return to play (1)[C].

Diagnostic Tests & Interpretation

Lab

Research conducted on more severe head injury suggests that many genetic and cytokine factors are induced (1).
These include insulin-like growth factor 1 (IGF-1), IGF-binding protein 2, fibroblast growth factor, copper-zinc superoxide dismutase 1 (SOD-1), nerve growth factor, glial fibrillary acidic protein (GFAP), and S-100 (1).
As yet, the significance of these factors in concussion is not fully known, and no routine laboratory testing is occurring (1).

Imaging

Cranial CT scan: Useful in acute imaging to rule out intracranial bleed. Consider if prolonged LOC or if symptoms are worsening or failing to resolve in a timely manner (1,3)[C].
Imaging usually contributes little to routine concussion management (1,3).
MRI modalities such as gradient echo and perfusion and diffusion imaging may diagnose structural lesions better than CT scan, but again, routine use of MRI does not add to concussion evaluation (1)[C].
Functional MRI (fMRI) may illustrate degree of symptoms and their resolution but is not yet part of standard concussion management (1).
Experimental imaging technology includes positron emission tomography (PET), diffusion tensor imaging, MRI spectroscopy, and functional connectivity (1).

Diagnostic Procedures/Surgery

Neuropsychological (NP) testing is used to assess cognitive function and help with return to play (RTP) decisions (1)[A].
Usually conducted when the athlete is asymptomatic as a final measure before clearance for RTP (3)[C]
Cognitive function often resolves after other symptoms, so NP evaluation can add helpful information (1)[A].
Should never be used as the only factor in deciding if an athlete should RTP (1,3)[C]
Consider in the case of a concussion with modifiers (1)[C].
Computerized tests such as the Automated Neuropsychological Assessment Metrics (ANAM), CogState, Concussion Recovery Index (CRI), Immediate Post-Concussive Assessment and Cognitive Testing (ImPACT), and HeadMinder, among others, facilitate administration and interpretation, especially among nonneuropsychologists (3).
In addition to a postconcussion symptom scale, the tests evaluate the following: attention, memory, processing speed, and reaction time (3).
The most effective use of NP testing involves comparing preinjury baseline testing with postinjury testing and using a test that accounts for confounding factors (eg, a practice effect) that occur with serial tests (3,10,14)[C].
The Reliable Change Index describes test-retest reliability and is a feature available with computerized tests (14).
A neuropsychologist may administer other formal NP testing if necessary, and neuropsychologists are often the most qualified to interpret any NP test (1)[C].
Balance testing adds valuable information to concussion assessment, especially when the athlete is having signs or symptoms of postural instability (1)[A].
The Sensory Organization Test is a computerized force plate system to evaluate postural sway under changing visual and somatosensory information (3).
The Balance Error Scoring Test (BESS) evaluates the ability of a person to hold without “error” 3 positions (legs together, single-leg stance, and tandem stance) with eyes closed and hands on the hips. The test is conducted on a firm and a foam surface (3).
BESS has been prospectively validated (3)[A].
A modified BESS is part of the SCAT 2 test.

Differential Diagnosis

Subdural hematoma, which may be acute or subacute (15)
Epidural hematoma, which can result in rapid deterioration after a “lucid interval” (15)
Intraparenchymal hemorrhage (15)
Diffuse axonal injury (DAI) or shear injury to white matter that leads to prolonged LOC and often causes residual deficits (15)
Second impact syndrome (SIS) is a rare yet often fatal process that occurs when an athlete who has not recovered completely from one concussion sustains a 2nd blow to the head. Cerebral edema and increased intracranial pressure result. The patient can decline rapidly as cerebral herniation occurs (4).
Trauma-induced migraine

Treatment

On-field management (1,3,13)[C]:
- Evaluate and treat ABCs as necessary.
- Perform C-spine immobilization if indicated, taking care to leave helmet in place.
- Perform baseline GCS and quick neurologic evaluation.
- Evaluate athlete for associated and other injuries (C-spine).
- If athlete is conscious and C-spine injury has been reasonably ruled out, take athlete to sideline for further testing, reevaluation, and/or observation.
- Immediately transfer athlete to a hospital when indicated (eg, prolonged LOC >5 min, focal neurologic deficit, decreased or deteriorating mental status, uncontrolled vomiting, suspected skull fracture).

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Sideline management:
- Continue to address first aid and exclude associated injuries such as a C-spine injury (1)[C].
- Physical and cognitive rest until asymptomatic (1)[C]
- A trained healthcare professional should conduct a detailed medical and neurologic assessment that includes balance assessment and cognitive evaluation (1,3)[C].
- Consider the administration of a test such as the SCAT 2 (1)[C].
- An athlete with any symptoms at rest or with exertion should not RTP (1)[C].
- Nonadult athletes (<18 yrs old) should not RTP the same day a concussion occurs (1)[C].
- Some evidence suggests that when assessing recovery by NP evaluation, high school students with concussion may take longer to recover than college students with concussion (16).
- Consider “modifiers” (symptom severity; associated signs such as LOC, amnesia, or concussive convulsions; a history of prior concussions; comorbid conditions such as ADHD; etc.) may dictate a more conservative approach (1).
- Consideration of same-day RTP can occur with adult athletes (1)[B].
- Arrange for observation (in-hospital for severe cases or situations where there is a lack of adequate supervision or by a medical provider, trustworthy friend, or family member) and serial examinations of the athlete several times over the 1st few hours after a concussion to monitor for deterioration or delayed symptoms (1,3)[C].

Ongoing Care

A 6-step graduated RTP protocol is endorsed in the work of the Concussion in Sport Group and by the American College of Sports Medicine (1,10,11,12)[C].
Athletes progress through each step for a period of at least 24 hr. Before moving forward in the protocol, athletes must be asymptomatic and not taking any drugs that would change or hide their symptoms.
If symptoms develop at one stage, the athlete should go back one level. Another attempt to progress to the next level can occur after a 24-hr rest period.
The 6 steps are as follows: No activity, light aerobic exercise, sport-specific training, noncontact training drills, full contact practice, and return to play.
This protocol sometimes may be expedited in an adult athlete.
An augmented RTP protocol might be appropriate in the situation of a concussion with modifying features, including in children.

Follow-Up Recommendations

After sustaining a concussion, an athlete should be evaluated by a medical professional prior to RTP (13)[C].
Emergent follow-up should be sought in the case of any of the following: focal neurologic deficit, declining mental status or LOC, uncontrolled vomiting, or worsening headache (3,13)[C].
Tylenol may be used to treat HA or other pain, but NSAIDs and aspirin should be avoided initially.
Athletes also should avoid sedating medicines or substances such as alcohol that may affect cognitive function.
An athlete should rest from all physical and mental activity while still having symptoms of a concussion. Physical rest includes avoiding activities such as physical education class or riding a bike to school, and mental rest includes school work, video games, texting, computer usage, etc. (1)[C].
After all symptoms have resolved without the use of medicine to mask complaints and an athlete sees a medical provider, a gradual RTP prescription likely will be recommended. This program might include starting with light aerobic activity and progressing from noncontact drills to contact drills over at least a 24-hr period per step provided that no symptoms appear with the addition of exercise (1).
It is important to be honest about the presence of symptoms because there is some evidence that if someone is incompletely recovered from a concussion and sustains another blow to the head, SIS, a rare yet often fatal process, can occur (4).

Patient Monitoring

A patient should not be left unsupervised following a concussion (1)[C].
A patient should be monitored for the following: focal neurologic deficit, declining mental status or LOC, and uncontrolled vomiting (3)[C].
Emergent medical care should be sought if any of the preceding occur (3)[C].

Prognosis

80–90% of concussions resolve within 7–10 days (1).

Complications

Depression is reported in retired former professional football players at higher incidence in those with a history of concussion compared with those without (1).
Chronic traumatic encephalopathy or cognitive impairment is more common among retired National Football League (NFL) players who sustained increasing numbers of concussions (17).
A small number of patients may develop postconcussion syndrome (PCS) (8,18).
There are limited data on the incidence and characterization of PCS, especially with respect to sports-related concussions (8,19).
This syndrome is characterized by persistent cognitive trouble (concentration deficits, memory difficulty), physical complaints (headache, fatigue), or emotional disturbances (irritability, depression) (15,18).
NSAIDs and antidepressants are used commonly to treat PCS, and psychological treatment also may help (19).
Athletes should not RTP when still symptomatic (1,3,4,10,11,12).
No evidenced-based guidelines exist for temporary or permanent disqualification after concussion (20).
Retirement from sports participation may be considered in the case of continued symptoms or objective exam findings, situations where a lesser impact creates concussion symptoms and the athlete takes longer to recover, or when an athlete sustains multiple concussions in one season (20).

References

1. McCrory P, Meeuwisse W, Johnston K, et al. Consensus statement on concussion in sport—The 3rd International Conference on concussion in sport, held in Zurich, November 2008. J Clin Neurosci. 2009;16:755–763.

2. Centers for Disease Control and Prevention (CDC). Nonfatal traumatic brain injuries from sports and recreation activities—United States, 2001–2005. MMWR Morb Mortal Wkly Rep. 2007;56:733–737.

3. Goldberg LD, Dimeff RJ. Sideline management of sport-related concussions. Sports Med Arthrosc. 2006;14:199–205.

4. Meehan WP, Bachur RG. Sport-related concussion. Pediatrics. 2009;123:114–123.

5. McCrea M, Hammeke T, Olsen G, et al. Unreported concussion in high school football players: implications for prevention. Clin J Sport Med. 2004;14:13–17.

6. Dick RW. Is there a gender difference in concussion incidence and outcomes? Br J Sports Med. 2009;43(Suppl 1):i46–i50.

7. Hootman JM, Dick R, Agel J. Epidemiology of collegiate injuries for 15 sports: summary and recommendations for injury prevention initiatives. J Athl Train. 2007;42:311–319.

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8. McCrory P, Johnston KM, Mohtadi NG, et al. Evidence-based review of sport-related concussion: basic science. Clin J Sport Med. 2001;11:160–165.

9. McIntosh AS, McCrory P, Finch CF, et al. Does Padded Headgear Prevent Head Injury in Rugby Union Football? Med Sci Sports Exerc. 2009.

10. Concussion (mild traumatic brain injury) and the team physician: a consensus statement. Med Sci Sports Exerc. 2006;38:395–399.

11. Aubry M, Cantu R, Dvorak J, et al. Summary and agreement statement of the First International Conference on Concussion in Sport, Vienna 2001. Recommendations for the improvement of safety and health of athletes who may suffer concussive injuries. Br J Sports Med. 2002;36:6–10.

12. McCrory P, Johnston K, Meeuwisse W, et al. Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004. Clin J Sport Med. 2005;15:48–55.

13. Wojtys EM, Hovda D, Landry G, et al. Current concepts. Concussion in sports. Am J Sports Med. 1999;27:676–687.

14. McCrory P, Makdissi M, Davis G, et al. Value of neuropsychological testing after head injuries in football. Br J Sports Med. 2005;39 (Suppl 1):i58–i63.

15. Bailes JE, Cantu RC. Head injury in athletes. Neurosurgery. 2001;48:26–45; discussion 45–46.

16. Field M, Collins MW, Lovell MR, et al. Does age play a role in recovery from sports-related concussion? A comparison of high school and collegiate athletes. J Pediatr. 2003;142:546–553.

17. Guskiewicz KM, Marshall SW, Bailes J, et al. Association between recurrent concussion and late-life cognitive impairment in retired professional football players. Neurosurgery. 2005;57:719–726; discussion 719–726.

18. Lee LK. Controversies in the sequelae of pediatric mild traumatic brain injury. Pediatr Emerg Care. 2007;23:580–583; quiz 584–586.

19. Ryan LM, Warden DL. Post concussion syndrome. Int Rev Psychiatry. 2003;15:310–316.

20. Kirkwood MW, Yeates KO, Wilson PE. Pediatric sport-related concussion: a review of the clinical management of an oft-neglected population. Pediatrics. 2006;117:1359–1371.

Additional Reading

Access the SCAT 2 at the following Web site: www.sportconcussions.com/html/SCAT2.pdf.

Codes

ICD9

850.0 Concussion with no loss of consciousness
850.11 Concussion, with loss of consciousness of 30 minutes or less
850.12 Concussion, with loss of consciousness from 31 to 59 minutes

Clinical Pearls

No one should RTP while still having the signs or symptoms of a concussion. In general, an athlete <18 yrs of age should not RTP the same day because there may be unrecognized symptoms initially or a delay in the development of symptoms. Also, the younger you are, the longer you will likely need to recover fully from a concussion. Receiving a 2nd blow to the head (even a minor one) while still suffering from the effects of the original concussion can lead to SIS, which results in severe brain swelling and often death.
The physician likely will prescribe a stepwise and gradual return to activity to begin after the patient is no longer experiencing symptoms. Developing any symptoms during this program will require additional rest before proceeding. In some cases, the physician may recommend additional testing such as balance testing or formal cognitive testing before a patient can RTP.
As yet, there is no specific cutoff number of concussions used to permanently disqualify an athlete. However, mounting evidence exists that the more concussions a person suffers, the worse he or she tends to do on various tests of brain function. Long-term data from retired professional football players suggest that increased numbers of concussions are associated with depression and permanent memory difficulty. Athletes should consider this risk of cumulative brain injury from multiple concussions when deciding whether or not to RTP.
While helmets cannot necessarily prevent concussions, proper headgear for sports should be worn to prevent other head injuries. Learning safe fundamentals of a given sport, such as the proper head-up tackling position in football, can help to reduce the occurrence and severity of concussions. Athletes should engage in respectful competition and should refrain from violent behavior.