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Concussion

Concussion. David Berkoff, MD Associate Professor Department of Orthopedics UNC. Disclosure.

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Concussion

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  1. Concussion David Berkoff, MD Associate Professor Department of Orthopedics UNC

  2. Disclosure • I have no relevant financial relationships with the manufacturer(s) of any commercial product(s) and/or provider(s) of commercial services discussed in this CME activity. I do not intend to discuss an unapproved/investigative use of a commercial product/device in my presentation

  3. Objectives • Pathophysiology • Epidemiology • Zurich updates • Grading Scales • Acute Management • Imaging • RTP Progression • Prevention • Why is this important? • Neuropsych testing • Referral? • Long term effects

  4. Concussion Definition • Concussion is defined as a complex pathophysiological processaffecting the brain, induced by traumatic biomechanical forces.Several common features that incorporate clinical, pathologicand biomechanical injury constructs that may be utilised indefining the nature of a concussive head injury include: • Concussion may be caused either by a direct blow to the head,face, neck or elsewhere on the body with an "impulsive" forcetransmitted to the head. • Concussion typically results inthe rapid onset of short-lived impairment of neurologic functionthat resolves spontaneously. • Concussion may result in neuropathologicalchanges but the acute clinical symptoms largely reflect a functionaldisturbance rather than a structural injury. • Concussionresults in a graded set of clinical symptoms that may or maynot involve loss of consciousness. Resolution of the clinicaland cognitive symptoms typically follows a sequential course;however it is important to note that in a small percentage ofcases however, post-concussive symptoms may be prolonged.

  5. Epidemiology • CDC reports approximately 300,000 concussions per year1 • High School FB estimates 3-20% rate per season • Approx. 62,816 MTBI in HS, 63% in football2 1Thurman D, Branche C, et al. J Head Trauma Rehabil., 1998;13, 1-8 2Powell JW, Barber-Foss KD. JAMA 1999;282:958-63

  6. Epidemiology in HS and Collegiate Athletes • Surveys to ATCs of 17,549 FB players over 3 yrs • 888 (5.1%) sustained a concussion • 131 (14.7% of the 888) sustained 2nd injury in the same season • Players with 1st concussion were 3x more likely to sustain a 2nd during the season • Artificial turf greater injury than grass • 30.8% of players RTP same day Guskiewicz KM, Weaver NL, Padua DA, Garrett WJ. Amer J Sports Med 2000; 28: 643-650

  7. Age Differences HS vs. College • Prospective study ‘97-00 • 371 college athletes, 183 HS athletes • 54 concussions • HS athletes still with deficits 7 days out (P < 0.005) • College improved to matched controls after 3 days Field M, Collins MW, Lovell MR, et. al. J Pediatr, 2003;142:546-53

  8. Unreported Concussions in HS • Retrospective, confidential survey from 1,532 high school FB players • 29.9% previous hx of concussion • 15.3% sustained one this season • 47.3% reported injury • 76.7% reported to ATC • Why not reported? • 66.4% felt not serious enough • 41.0% did not want to be withheld from competition • 36.1% unaware of sx of concussion McCrea M, Hammeke T, et al. Clin J Sport Med, 2004,14: 13-17

  9. Epidemiology • Today there is a 4-20% chance of head injury • Depends on position • Up to 4 deaths per year from MTBI • HS players have higher incidence of catastrophic head injuries than college players • For soccer head injury • More common cause in head-to-head or head-to-body impacts, not heading the ball

  10. More Recent Epidemiology • Retired FB players who sustained concussion • One to two concussions = 1.5x more likely to suffer from depression • Three or more = 3x more likely • Also more cogitive deficits • Earlier onset Alzheimer’s • 1994, NFL formed Commission on MTBI Guskiewicz K, et al. Med Sci Sports Exerc 2007;39(6):903-9 Guskiewicz K, et al. Neurosurgery 2005;57(4):719-26

  11. Position Prevalence • In general offensive players have more MTBI than defensive players • QB highest risk (1.62 per 100 game positions) • WR 1.23, TE 0.94, DB 0.93 • All backs 3x the risk of all lineman Casson I, Pellman E, Viano D. Neurol Clin 26 (2008) 217-241

  12. Epidemiology • 60.5% of MTBI associated with tackling • 29.5% blocking • 67.7% related to striking helmet on helmet Casson I, Pellman E, Viano D. Neurol Clin 26 (2008) 217-241

  13. Some Other Thoughts on Concussion.... • Brains are individual and dynamic • would same blow to 100 age and gender matched athletes produce same concussion symptoms and recovery? • some would argue there is more inter-individual difference in brain function vs other organs/injuries • Also concussion is “dynamic” based on: • sleep deprivation, hydration, fatigue, comorbid states McKeag D, Kutcher J. Clin J Sport Med Sept 2009

  14. Concussion penumbra • similar to ischemic stroke • ischemic penumbra, tissue around the stroke that remains susceptible to risk of dying • Concussion penumbra • area of injury more susceptible to extension or increased severity of injury • factors include physical and mental exertion, sleep deprivation, dehydration, hypoglycemia McKeag D, Kutcher J. Clin J Sport Med Sept 2009

  15. The Brain Awareness Problem • Concussion remains a diagnosis dominated by subjective information given by athlete while the clinician seeks objective data to support clinical decisions • is management affected by “honesty” of athlete • or anosognosia (the state of being unaware of one’s own neurologic deficit) aka.... loss of introspection • has been described in many brain diseases McKeag D, Kutcher J. Clin J Sport Med Sept 2009

  16. Pathophysiology of Concussion Cascade • K+ and glutamate release with initial cell injury • Inc. glucose utilization to bring K+ back into cell through ATP pumps • CBF decreases = less glucose = METABOLIC MISMATCH, which exacerbates injury • Ca++ accumulates which inc. protease activation and results in cell death • Axonal “shear injury” is also discussed with post-concussion syndromes

  17. Concussion Evaluation • So we as clinicians need more objective data for decision making in concussion injury to: • Assess severity of acute injury • Prevent long term sequale • Dementia, depression

  18. Objective Concussion Assessment • 3 Main pathways: • Biomechanical assessment • Measure force of injury • Neuropsychological and Balance testing • Measure function • Neuroimaging (fMRI) • Function and structure • Blood markers for MTBI are also researched • S100B

  19. Biomechanics of Head Injuries • Two types of biomechanical stresses • Acceleration/deceleration • Linear, tensile, and compressive forces • Rotational or angular acceleration • More likely to result in injury to the brain • Holbrun 1943 and Gennerelli later

  20. Conclusions • Impact speed of 7m/s or 15.6mph and 90g (70-75g) offer a line a delineation between concussion vs no concussion

  21. Striking vs Struck Players • Why don’t striking players get MTBI as often? • Impact velocities are same for both • Change in velocity and peak translational accelerations are lower • Effective mass of striking player is much greater • Includes torso mass when hit with top of helmet • “head-down” position increases mass by 67% • Rotational velocities were similar to concussed players Pellman E, Viano D, Tucker A, et al. Neurosurgery 2003;53:1328-41

  22. Neck Strength • HIC (best assessment of concussion risk) • Is proportional to: • Change in velocity to head displacement • Small decreases in change of head velocity will have large effect on concussion risk as this affects the HIC by a factor to the fourth power • Stronger necks = diminished head displacement • whiplash anybody? Viano D, Casson I, Pellman E. Neurosurgery 2007;61:313-28

  23. Neck Strength • A 10% reduction in head velocity will result in 34% reduction in HIC • May explain increased concussions in: • HS athletes • Some female athletes • Different positional FB players

  24. On-Field Evaluation • Any player with suspected concussion should: • be evaluated with standard approach • rapid assessment from Maddock’s questions (Pocket SCAT2) and/or SAC • SCAT2 or similar later • ABCs, r/o other serious injury • assess c-spine

  25. On-Field Assessment • Serial 7s • WORLD backwards • Months backwards • number sets backwards (7-9-1) • 3 word recall • Player affect and personality changes

  26. Acute Evaluation of Concussion • standard orientation questions (eg, time, place, person) have been shown to be unreliable in the sporting situation • Cognitive features: unaware of period, opposition, or score of game; confusion; amnesia; loss of consciousness; and unaware of time, date, or place

  27. http://www.cces.ca/files/pdfs/SCAT2[1].pdf

  28. Concussion Consensus History • 2001 Vienna • lacking consistent diagnosis and treatment guidelines • 2004 Prague • attempted to redefine concussions, management • 2008 Zurich • SCAT2, abolish simple vs complex, same day conc.

  29. A Word of Caution! • Consensus statements in general: • are products of compromise • often anecdotal and agreements by “experts” • sometimes not evidenced based • but in the world of concussion, it is the best we have!

  30. 2008 Zurich Consensus • Third International Conference on Concussion in Sport • Paul McCrory, MBBS, PhD (chair); Karen Johnston, MD, PhD; Willem Meeuwisse, MD, PhD; Mark Aubry, MD; Robert Cantu, MD; Mick Molloy, MB; Jiri Dvorak, MD

  31. Loss of Consciousness 8-11% experience LOC

  32. Symptoms Gioia, G, Collins, M, Isquith, P; J Head Trauma Rehab. Vol. 23, No. 4 pp.230-242. 2008

  33. Concussion Grading Scales:From 2008 Zurich Consensus Statement • No single system was endorsed Ex. Data driven Cantu grading system for concussion Grade 1 (Mild) No LOC, PTA, PCSS < 30 minutes Grade 2 (Moderate) LOC < 1 min. or PTA > 30 min. < 24 hrs,PCSS > 30 min. < 7 days Grade 3 (Severe) LOC 1 minute or PTA 24 hours, PCSS > 7 days Abbreviations: LOC, loss of consciousness; PTA, post-traumatic amnesia; PCSS, postconcussive signs/symptoms other than amnesia. Cantu RC. Post traumatic (retrograde/anterograde) amnesia: pathophysiology and implications in grading and safe return to play. J Athletic Training 2001;36(3):244 –8. • LOC as the primary measure of injury severity has acknowledged limitations • LOC > 1 min  risk factor for more severe injury • Amnesia vs LOC • Amnesia, not LOC appears more predictive of symptom and neurocognitive deficits following concussion1 • Retrograd amnesia is poorly reflective of severity of injury. • Presence of post-concussion sx may be more important than the presence and/or duration of amnesia sx alone 1. Collins, Iverson, Lovell, Mc Keag et al. Clin J Sport Med Vol. 13, No.4 2003

  34. Concussion Classification • Abandoned by 2008 Zurich Consensus Statement • Retrograde system • Simple-- an athlete suffers an injury that progressively resolves without complication over 7 to 10 days (* 80-90% of concussions) • Complex-- athletes suffer persistent symptoms (including persistent symptom recurrence with exertion), specific sequelae (eg, prolonged LOC [> 1 minute]), or prolonged cognitive impairment following the injury * Still recognized by Zurich that 80-90% fit into this criteria.

  35. Imaging • Neuroimaging • conventional structural neuroimaging is usually normal in concussive injury • CT or MRI should be employed whenever suspicion of a structural lesion exists • Prolonged disturbance of conscious state, focal neurological deficit, seizure activity, or persistent clinical or cognitive symptoms • fMRI may be of value in managing complex concussions and post-concussion symptoms

  36. MRI Findings in MTBI • Abnormalities on magnetic resonance imaging seen acutely following mild traumatic brain injury: correlation with neuropsychological tests and delayed recovery. • 80 persons with MTBI • 26 with non-specific MRI findings • 5 traumatic findings • Although non-specific abnormalities are frequently seen, standard MRI techniques are not helpful in identifying patients with MTBI who are likely to have delayed recovery Hughes DG, Jackson A, et al. Neuroradiology. 2004 Jul;46(7):550-8

  37. fMRI • May useful in cases of post-concussion syndrome ccs.fau.edu

  38. fMRI Findings in MTBI • Functional abnormalities in symptomatic concussed athletes: an fMRI study • 16 concussed athletes (15 symptomatic) • 8 controls • using blood oxygen level dependent (BOLD) fMRI • Conclusion: potential of fMRI, in conjunction with the working memory task, to identify an underlying pathology in symptomatic concussed individuals with normal structural imaging results. • Localize concussion • ? Validate Neuropsych testing • Increased sensitivity Chen JK, Johnston KM, et al. Neuroimage. 2004 May;22(1):68-82.

  39. RTP issues • No return while symptomatic • Prague: no return same day • Zurich recognizes some instances for same day RTP is safe and acceptable. • Caution with collegiate and below (esp. < 18) • Have standard exam (SCAT) • Expert Opinion2 • RTP if Sx clear rapidly and asymptomatic w/ physiologic challenge • Grade 1 Concussions in HS Athletes1 • 43 HS athletes dx with grade 1 concussion • Underwent neuropsych testing baseline and 2x during 1st week of injury • 36h post-injury, dec. in memory and inc. in sx 1.Lovell M, Collins M, et al. Amer J Sports Med 2004;32: 47-54 2. Standaert C, Herring S, Cantue R. Arch Phys Med Rehabil Vol 88, August 2007

  40. Second Impact Syndrome • Marked increase in cerebral swelling suddenly after a 2nd concussion in which the first has not healed • Debated as a true clinical entity • Some view one hit enough for sx • Usually adolescents N.C. prep football player dies of brain injury Sunday, August 24, 2008 Assistant coach said, “was hit on the first play of the game nearly the same way he was hit on the play in which he was injured.”

  41. RTP: Management and Rehabilitation • Acute response. When a player shows any symptoms or signs of a concussion: • 1.The player should not be allowed to return to play in the current game or practice. • 2.The player should not be left alone, and regular monitoring for deterioration is essential. • 3.The player should be medically evaluated following the injury. • 4.Return to play must follow a medically supervised, stepwise process.

  42. RTP • Rehabilitation • The athlete must be completely asymptomatic and have normal neurological and cognitive evaluations prior to the start of the rehabilitation program.

  43. RTP Protocol Adapted from the Consensus Statement on Concussion in Sport: The 3rd International Conference on Concussion in Sport Held in Zurich, November 2008 JAT 2009

  44. Neuropsychological Testing • Inherent problems with most neuropsychological tests include: • the normal ranges, sensitivity, and specificity of tests • practice or learning effect • observation that players may return to baseline while still symptomatic • motivation to do well on test compared to baseline • Zurich– not usually needed in simple cases. Testing while symptomatic is of little value. • How often to baseline athletes?

  45. ImPACT Testing • Immediate Postconcussion Assessment and Cognitive Testing From Personal Files

  46. Postconcussive Activity: • Retrospective study • 95 athletes – 80 males, 15 females; mean age 16 • Evaluated relationship of activity intensity to symptoms and neurocognitive outcomes over 30 days • Athletes that participated in school activity and light activity at home performed better. • Limitations: • Did not utilize any concussion grading scale • Did not standardize light activity Majerske, C, et al. Concussion in Sports: Postconcussive Activity Levels, Symptoms, and Neurocognitive Performance. J of Ath Tr. 2008;43(3):265-274.

  47. Pharmacologic Treatment of Concussion • There is NO evidence for pharmacologic treatment of MTBI • ?Pathophysiology of axonal injury in MTBI • Main areas of use are symptom management • acetaminophen, NSAIDs acutely (careful not to mask symptoms) • Anti-depressants, ADD medications, sleep aides for post-concussive syndrome management McCrory P. Should We Treat Concussion Pharmacologically? Br J Sports Med 2002

  48. Prevention of Concussion • Prevention • The brain is not an organ that can be conditioned to withstand injury. Thus, extrinsic mechanisms of injury prevention must be sought. • Helmets • Mouth guards • Rule Changes (and Referees) • Neck conditioning programs

  49. Protective Equipment

  50. Summary • Improved helmet design and rule changes have markedly decreased severe head and cervical spine injuries in football • More research is needed on biomechanical forces in concussive injuries • Still no “threshold” for concussions • Many factors for injury patterns, not just biomechanics • Neck strengthening programs most likely decrease concussion risk • HS athletes more susceptible • Less neck strength • underdeveloped nervous system • Tackling techniques

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