Concussion.

Case Presentation

You are the sideline doc at the conference championship football game. You are called to the field to examine your QB who was sacked in the last play of the first half with his head hitting the firm fall turf. He moves all extremities, has no neck pain, no loss of consciousness, but doesn't remember getting hit, the quarter, or who the opponent is. You walk him to the sideline and 15 minutes later his memory deficit is only for the play on which he was injured. What are other pertinent details to elicit on history and physical exam? Can he play again in that game?

Introduction

There have been three consensus conferences on concussion in sport. The first was convened almost 40 years ago, when the Congress of Neurologic Surgeons defined concussion as "a clinical syndrome characterized by the immediate and transient post-traumatic impairment of neural function such as alteration of consciousness, disturbance of vision or equilibrium, etc., due to brain stem dysfunction" (1). We still use this functional and clinical definition today, though other definitions have been proposed. The American Association of Neurology defines concussion as "any trauma induced alteration in mental status that may or may not include a loss of consciousness" (2).

In Vienna, Austria in 2001, the International Ice Hockey Federation, the Federation Internationale de Football, and the International Olympic Committee convened the 1st International Symposium on Concussion. Grading systems proposed by various researchers prior to the Vienna conference were called into question because they failed to serve as a reliable assessment of the severity of the injury. Severity seemed to correlate best with number and degree of concussion symptoms and how long those symptoms persisted. In the fall of 2004, the 2nd International Symposium convened in Prague, and issued guidelines that attempt to change significantly the way we handle athletes with concussion.

No Return

One of the most sweeping changes of the Prague document is that no player should be allowed to return to play in the same contest following a concussion. Even more stringent is the recommendation for a period of "cognitive rest" to limit activities of daily living and scholastic activity while symptomatic. The reason for this limitation is to avoid "second impact syndrome," a phenomenon originally described by Saunders and Harbaugh in 1984 (3), in which an athlete suffers a second concussion before recovering completely from the first. This can result in more varied, severe, and long lasting symptoms, even death, with the second impact, and those symptoms are often caused by minor impact. It is felt to result from loss of autoregulation to the intracranial blood supply, sometimes resulting in increased intracranial pressure and possible herniation (4).

Age

One of the key pieces of information lacking in the case described is the age of the player. Though no age limits are included in the Prague guideline, it is clearly most applicable in the pediatric age group, based on studies showing lower age groups being at increased risk of damage or prolonged recovery from head injury (4), (5), (6), (7). In fact, there have been no clearly defined cases of "second impact syndrome" in the adult athlete in sports other than boxing (8).

Prior History

McCrea, Guskiewicz, and others have shown conclusively that athletes with prior history of completely recovered concussion are more likely to undergo subsequent concussion (9), (10), and subsequent concussions are likely to be more severe. In our case above, consideration of the athlete's prior history would be of great importance in attempting to assess future risk.

Mechanism of Injury

A blow to a stationary but moveable head causing sudden acceleration tends to produce maximum injury to the brain immediately beneath the point of impact--a "coup" injury. A blow to a moving head causing immediate deceleration causes damage opposite the point of impact--a "contrecoup" injury. Neither of these mechanisms predicts prognosis. It is known, however, that blows causing rotation of the brain produce shearing forces, which are tolerated more poorly than either coup or contrecoup injury (11).

Symptoms and Signs

Though loss of consciousness may be the most attention-getting symptom of concussion, it is neither the most common nor the most serious. Headache, seen in up to 85% of concussed athletes, is the most common symptom. Amnesia, according to Lovell and colleagues (12), (13), is most predictive of a prolonged neurocognitive deficit. Other symptoms include nausea, double or blurred vision, dizziness, fatigue, feeling foggy or sluggish, and difficulty with concentration.

The athlete may appear slightly dazed, be slow to answer questions or to respond to teammates. Amnesia for the event itself is very frequent, but may include inability to remember the score, the opponent, the location of the game, or getting to the sidelines after the injury. The athlete should undergo frequent reassessment on the sidelines to assure that there is no deterioration, and the helmet or other essential equipment should be kept by the medical team to assure that the athlete does not return to play.

Symptoms and signs should be carefully documented with a SCAT (Sport Concussion Assessment Tool) score (see pages 12 and 13). This may be important both in documenting the initial diagnosis and in assessing improvement if more detailed neuropsychological testing is not available.

Lovell, Collins, Leclerc, and others have brought routine baseline and post-injury neuropsychological testing within the scope of most high school and college athletic teams. The athletes are tested universally at the beginning of a season with a computer-based program and are retested if injured during the season. Data from this detailed and objective testing has demonstrated that effects of concussion are much longer lasting than had been thought. This data, in turn, has generated the concern expressed by the Prague attendees over immediate return to play, though they do not recommend that such testing "be the sole basis of management decisions, either for continued time out or return to play" (14). Nevertheless, it would be imprudent to return the athlete to competition prior to stabilization near baseline.

Steps in Returning to Play

The Prague recommendation is that "when a player shows ANY symptoms or sign 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; regular monitoring for deterioration is essential over the initial few hours following injury.

3) The player should be medically evaluated following the injury.

4) Return to play must follow a medically supervised stepwise process."

When sent home post-concussion, a responsible party accompanying the player should be made aware of the situation. The athlete should avoid medications other than acetaminophen, alcohol, and recreational drugs including tobacco. Monitoring need be no more extensive than waking him/her once during the night to make sure that he/she is responding appropriately. Instructions for whom to call for follow-up, should deterioration occur, should be provided.

Premature activity of any sort may jeopardize the biochemical healing process following an injury. Thus, the Prague conferees suggest a stepwise return to activity with each phase lasting at least 24 hours, longer if the athlete shows continuing signs or symptoms of impairment. These steps are:

1) No activity, complete rest. Once asymptomatic, proceed to level 2.

2) Light aerobic exercise such as walking or stationary cycling, no resistance training.

3) Sport specific exercise (e.g., skating in hockey, running in soccer), progressive addition of resistance training at levels 3 or 4.

4) Non-contact training drills.

5) Full contact training drills after medical clearance.

6) Game play.

Neuroimaging

Though imaging modalities such as PET and SPECT scanning, as well as functional MRI, have increasingly been able to detect abnormalities in concussed brains, the role for these experimental techniques in assessment of either severity or recovery of concussion has not yet been established. The consensus currently is that these techniques are still at the early stages of development and have nothing to add to the workup of the concussed athlete. CT and MRI are to be used only when structural brain damage is suggested based on clinical evidence of focal abnormality, seizure activity, or persistent or progressive cognitive deficit.

Equipment and Prevention

While there is little doubt that helmets prevent head injury in hockey (15), football, and lacrosse, no benefit has been seen using helmets in soccer. Mouthguards have been shown to prevent dental injury, but do not seem to affect the incidence of concussion. Probably the most successful efforts at avoiding head and neck injuries are rule changes with strict enforcement. Football's anti-spearing rule adopted in 1976 dramatically reduced the number of spinal cord injuries seen yearly, and helmet-to-helmet penalties may improve the situation further. Fair play rules in hockey are showing an 80% injury reduction rate (16). Artificial turf initially was felt to increase concussion rates, but untested improvements in the resiliency of the surface hold promise.

Summary

Concussion is one of the most common injuries in sport. Though the actual incidence is unreported and unknown, about 5% of high school and college football players are concussed yearly. Rule changes and improvements in equipment promise to lower the incidence of concussion, but increasing strength and speed of athletes threaten to raise it. Inexpensive computer-based neuropsychological testing has increased detection of neurologic deficits following concussion, and this has increased the conservatism and stringency of guidelines, emphasizing the potential dangers of immediate return-to-play.

REFERENCES

(1.) Congress of Neurological Surgeons. Committee on head injury nomenclature: glossary of head injury. Clin Neurosurg 1966; 12:386-94.

(2.) American Academy of Neurology. Practice parameter: the management of concussion in sports (summary statement). Report of the Quality Standards Subcommittee. Neurology 1997; 48:581-5.

(3.) Saunders RL, Harbaugh RE. Second impact in catastrophic contact-sports head trauma. JAMA 1984; 252:538.

(4.) Cantu RC. Second impact syndrome. Clin Sports Med 1998; 17(1):37-44.

(5.) Rivara E. Childhood injuries III: Epidemiology of non-motor vehicle head trauma. Dev Med Child Neurol 1984; 26(1):81-7.

(6.) Bruce DA, Alavi A, Bilaniuk L, Dolinskas C, Obrist W, Uzzell B. Diffuse cerebral swelling following head injuries in children: the syndrome of malignant brain edema. Journ Neurosurg 1981; 54:170-8.

(7.) Field M, Collins MW, Lovell MR, Maroon JC. Does age play a role in recovery from sports-related concussion? A comparison of high school and collegiate athletes. Journ Pediatr 2003; 142:546-53.

(8.) McCrory PR. Second impact syndrome. Neurology 1998; 50(3):677-83.

(9.) Guskiewicz KM, McCrea M, Marshal SW. Cumulative effects associated with recurrent concussion in collegiate football players: the NCAA Concussion Study. JAMA 2003; 290:2549-2555.

(10.) McCrea M, Guskiewicz KM, Marshall SW. Acute effects and recovery time following concussion in collegiate football players. JAMA 2003; 290:2556-2563.

(11.) Guskiewicz KM, et al. National Athletic Trainers' Association position statement: Management of Sport-related concussion. Journ of Athletic Training 2004; 39(3):280-97.

(12.) Lovell M, Collins M, Bradley J. Return to play following sports-related concussion. Clinics in Sports Med 2004; 23(3):421-41.

(13.) Collins MW, Iverson GL, Lovell MR, McKeag DB, Norwig J, Maroon JC. On-field predictors of neuropsychological and symptom deficit following sports-related concussion. Clin J Sport Med 2003; 13:222-9.

(14.) McCrory P, et al. Summary and agreement statement of the 2nd international conference on concussion in sport, Prague 2004. Clin J Sport Med 2005; 15(2):48-55.

(15.) Kraus JF, Anderson BD, Mueller CE. The effectiveness of a special ice hockey helmet to reduce head injuries in college intramural hockey. Medicine and Science in Sports, 1970; 2(3):162-64.

(16.) Roberts WO, Brust JD, Leonard B, Hebert BJ. Fair-play rules and injury reduction in ice hockey. Archives of Pediatr and Adolescent Med 1996; 150(2):140-45.

by Robert S. Fawcett, MD, MSc, CAQ Sports Medicine

Dr. Robert Fawcett is Medical Director and Assistant Program Director for the York Hospital Family Medicine Residency Program in York, Pennsylvania. He is also a regular speaker at AMAA's sports medicine symposiums and each year brings a team of residents to provide care in the medical tent at the Marine Corps Marathon.