Concussion The Basic Science

Arturo Aguilar MDBoston University

June 1, 2011

Disclosure

Neither I, Arturo Aguilar, nor any family

members, have any relevant financial

relationships to be discussed, directly or

indirectly, referred to or illustrated with or

without recognition within the presentation

Objectives

- History - Incidence - Definition - Pathology - Symptoms / Diagnosis - Grading - Risk

History

A short lived period of posttraumatic neurologic dysfunction followed by full recovery has been described for over 3,000 years.1

From the Latin term cerebrum commotum2

“...paralysis of cerebral function” Dr. LaFrancus (13th century)2

Incidence

Approximately 1.6-3.8 million concussions each year in the U.S.3

10% of college football players sustain brain injuries each season.4

Concussions are the second most common injury in college football and women's soccer. Fourth most common in men's soccer, field hockey, women's volleyball.5

Up to 85% of concussions go undiagnosed.6

Consensus Guidelines

International Symposia on Concussion in Sport (Vienna 2001, Prague 2004, Zurich 2008)7,9

IIHF, FIFA, IOC Physicians, Neuropsychologists, sports

administrators, basic scientists Original research, previous guidelines Level C evidence

Definition

A complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces. [There are] several common features... (Consensus Statement of Concussion in Sport 3rd International Conference on Concussion in Sport. Zurich 2008)

Definition7

Common Features 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.

Typically results in the rapid onset of short lived impairment of neurologic function that resolves spontaneously.

...acute clinical symptoms largely reflect a functional disturbance rather than a structural injury.

Definition7

Concussion results in a graded set of clinical symptoms that...may not involve loss of consciousness.

Resolution of clinical/cognitive symptoms typically follows a sequential course [but]...in a small percentage of cases, post-concussive symptoms may be prolonged.

No abnormality seen on standard structural neuroimaging.

Pathophysiology1

No existing animal or other experimental model that accurately reflects a sporting concussive injury.

In animal models there is a complex cascade of biochemical, metabolic, and gene expression changes.

Unclear application to humans Anesthetized animals-blurs acute effects Symptom interpretation Different mechanical factors of smaller brains

Diagnosis / Symptoms8

Observed Dazed, stunned Confusion, forgetful Clumsy/balance

issues Speaks slowly Loss of

consciousness Mood, behavior,

personality changes

Reported

Headache, pressure

Nausea, vomiting

Dizzy

Blurred vision

photo/phono-phobia

Foggy, fatigue, hazy

Memory/focus issues

Feeling down/not right

Clinical Domains of Concussion7,8

Symptoms Physical Signs

Behavioral Signs

Cognitive Impairment

Sleep Disturbance

headache Loss of Consciousness

Irritability Slowed Reaction Time

Drowsiness

Nausea/vomiting Amnesia Depression Difficulty Concentrating

Insomnia

Dizzy Balance Issues Anxiety Memory Loss

Fatigue Tonic Clonic Activity

More Emotional Foggy Feeling

Blurred Vision Personality Changes

Forgetful

Photo/Phono- Phobia

Dazed / Stunned

Not Feeling Right

Diagnosis Difficulty5

“Perhaps the most challenging aspect of managing...concussion[s] is recognizing the injury, especially in [those] with no obvious signs that a concussion has actually occurred.”(NATA Position Statement: Management of Sport Related Concussions. 2004)

Rationalizing symptoms Uneducated regarding the seriousness Fear of limiting participation Popular media around professional return to

play

Concussion Grading7

25 concussion grading / management systems (2004)4,11

Symptoms, LOC

Lack evidence Abandon grading scales and (simple vs

complex) classifications. (Zurich 2008)

Second Impact Syndrome

Concussion and Risk: Fact or Fiction7

-If you had loss of consciousness you had a more severe concussion.

Fiction

-The majority of concussion symptoms last 7-10 days.

Fact

-If you have had a concussion in the past your next is likely to last longer.

Fact

Concussion and Risk: Fact or Fiction 3,9

-Once you sustain a concussion, you are 3-4x more likely to sustain a concussion again.

Fact

-If you have the A4 allele of the Apo E4 gene, you are more likely to sustain a concussion than those who do not.

Fiction

-

Concussion and Risk: Fact or Fiction 3,9

-If you wear the proper protective gear you are less likely to sustain a concussion.

Fiction

-By modifying some rules in sport, we may be able to reduce the risk of concussion in athletes.

Possibly

Summary

-Concussions are common

-Diagnosis: Mechanism + sign/symptom

-Think about the reasons we miss concussions

-There is a consensus statement to help guide diagnosis and management

-There are still many things we don't know yet, these are just guidelines.

References

1 McCrory P, Johnston K., Mohtadi N., Meeuwisse W” Evidence-Based Review of Sport-Related Concussion: Basic Science” Clinical Journal of Sports Medicine. (2005): Vol15 Num 6

2 Solomon G, Johnston K, Lovell M. The Heads-Up on Sport Concussion. United Graphics, USA. 2006

3 Davis G, Iversion G, Guskiewicz K, Ptito A, Johnston K. “Contributions of neuroimaging, balance testing, electrophysiology and blood markers to the assessment of sport-related concussion” British Journal of Sports Medicine. (2009); 43

4 Asplund C, McKeag D, Olsen C. “Sport-Related Concussion. Factors Associated With Prolonged Return to Play” Clinical Journal of Sports Medicine (2004); 14:339-343

5 Guskiewicz K, Bruce S, Cantu R, Ferrara M, Kelly J, McCrea M, Putukian M, McLeod T. “National Athletic Trainers' Association Position Statement: Management of Sport-Related Concussion” Journal of Athletic Training (2004); 39(3):280-297

6 Harmon MD, Kimberly “Assessment and Management of Concussion in Sports.” Harmon MD, Kimberly “Assessment and Management of Concussion in Sports.” American Family PhysicianAmerican Family Physician. (1999) ; 60:887-89. (1999) ; 60:887-89

7 McCrory, Johnston, Meeuwisse, Aubry, Cantu, Dvorak, Kelly “Summary and Agreement Statement of the 3McCrory, Johnston, Meeuwisse, Aubry, Cantu, Dvorak, Kelly “Summary and Agreement Statement of the 3 ndnd International International Conference on Concussion in Sport, Zurich, 2008.” Conference on Concussion in Sport, Zurich, 2008.” Clinical Journal of Sports MedicineClinical Journal of Sports Medicine. (2009) Vol 19 Number 3. (2009) Vol 19 Number 3

8 “Heads Up Facts for Physicians About Mild Traumatic Brain Injury (MTBI)” “Heads Up Facts for Physicians About Mild Traumatic Brain Injury (MTBI)” U.S. Department of Health and Human ServicesU.S. Department of Health and Human Services. . http://www.cdc.gov/ncipc/tbi/Facts_for_Physicians_booklet.pdf

9 McCrory, Johnston, Meeuwisse, Aubry, Cantu, Dvorak, Graf-Baumann, Kelly, Lovell, Schamasch “Summary and Agreement McCrory, Johnston, Meeuwisse, Aubry, Cantu, Dvorak, Graf-Baumann, Kelly, Lovell, Schamasch “Summary and Agreement Statement of the 2Statement of the 2ndnd International Conference on Concussion in Sport, Prague 2004.” International Conference on Concussion in Sport, Prague 2004.” Clinical Journal of Sports MedicineClinical Journal of Sports Medicine. (2005) . (2005) Vol 15, Number 2Vol 15, Number 2

10 Kissick J, Johnston K. “Return to Play After concussion” Clinical Journal of Sports Medicine. (2005); 15:426-431