Sickle Cell Trait

1. Sickle Cell Trait Ron Courson, ATC, PT, NREMT-I, CSCS Director of Sports Medicine University of Georgia Athens, GA University of Georgia Sports Medicine

2. Objective Leading causes ofnon-traumatic sports deaths in high school and college athletes: • cardiovascular conditions • hyperthermia (heatstroke) • acute rhabdomyolysis related to sickle cell trait • asthma • The objective of this presentation is to: • raise awareness of this condition • provide measures to reduce the risk of exertional collapse related to sickle cell trait Van Camp et al. Med Sci Sports exercise. 1995; 27:641-647

3. Introduction • Sickle cell trait is the inheritance of one gene for sickle hemoglobin and one for normal hemoglobin • During intense or extensive exertion, the sickle hemoglobin can change the shape of red cells from round to quarter-moon, or “sickle.” • This change, exertional sickling, can pose a grave risk for some athletes

4. Inter-Association Task Force on Sickle Cell trait and the Athlete • February 2007; Dallas, TX • 40 representatives from 22 professional organizations met and drafted a consensus statement to raise awareness of sickle cell trait and to provide measures to reduce the risk of exertional collapse related to sickle cell trait

5. IntroductionWho has Sickle Cell Trait? • ~ 8-10% of the U.S. African-American population has sickle cell trait • 1 in 12 African-Americans versus 1 in 2000 to 1 in 10,000 Caucasian-Americans) • condition of inheritance versus race • sickle cell gene is common in people whose origin is from areas where malaria is widespread • over the millennia, carrying one sickle cell gene fended off death from malaria • Only ~ 1% has sickle cell disease

6. IntroductionWho has Sickle Cell Trait? • SCT is also found in non-African-Americans as well, but less frequently • Mediterranean, Middle Eastern, Indian, Caribbean and South and Central American ancestry

7. Introduction • Research shows how and why sickle red cells can accumulate in the bloodstream during intense exercise • sickle cells can “logjam” blood vessels and lead to collapse from ischemic rhabdomyolysis, the rapid breakdown of muscles starved of blood • major metabolic problems from explosive rhabdomyolysis can threaten life • sickling can begin in 2-3 minutes of any all-out exertion – and can reach grave levels soon thereafter if the athlete continues to struggle

9. Deaths After Sickling Collapse in College Football • Up to 20 college football players have died after sickling in training, and although in some the proximate cause of death has been debated (and litigated), the setting and syndrome in most are similar

10. Sickle Cell Trait in the Military • A noted epidemiological study in 1987 strengthened the link between sickle cell trait and sudden death during physical training. Of all deaths that occurred among two million enlisted recruits during basic training in the U.S. Armed Forces over the five years from 1977 through 1981, the risk of sudden unexplained death in black recruits with sickle trait was 28 times higher than in black recruits without sickle trait and 40 times higher than in all other recruits. Kark JA. N Eng J Med. 1987; 317:781-7

11. Sickle Cell Trait and Strenuous Exercise • Strenous exercise evokes four forces that foster sickling: • severe hypoxemia • metabolic acidosis • hyperthermia in muscles • Red blood cell dehydration

12. Sickling Collapse The harder and faster athletes go, the earlier and greater the sickling. That is why sickle collapse occurs sooner (at a shorter distance) in top college football players sprinting all out (their “drop zone” is often 800-1,200 m.) than in military recruits trying to run 1-3 miles. Sickling can begin in only 2-3 minutes of sustained sprinting – or in any other sustained all-out exertion - and sickling can soon increase to grave levels if the symptomatic athlete tries to exceed his limits or is urged by the coach to push beyond pain and weakness. Any cramping, struggling, or collapse in a sickle-trait athlete must be considered sickling--a medical emergency--until proved otherwise. Eichner ER. Gatorade Sports Science Library. SSE # 103. 2007

13. Exertional Sickling • heat, dehydration, altitude, and asthma can increase the risk for and worsen sickling, even when exercise is not all-out • despite telltale features, collapse from exertional sickling in athletes is under-recognized and often misdiagnosed • sickling collapse is a medical emergency

14. Introduction • TF recommends confirming sickle cell trait status in all athletes’ preparticipation physical examinations. • As all 50 states screen at birth, this marker is a base element of personal health information that should be made readily available to the athlete, the athlete’s parents, and the athlete’s health care provider, including those providers responsible for determination of medical eligibility for sports participation. • TF maintains that knowledge of sickle cell trait status is the gateway to education and simple precautions that can prevent sickling collapse and enable sickle cell trait athletes to thrive in sport. • If the athlete lacks documentation, TF recommend screening to determine his/her sickle trait status. Inter-Association Task Force on Sickle Cell Trait and the Athlete

15. Sickle Cell Trait Testing • Simple blood test • Establishing testing program • What to do if the test is positive? • athlete education • genetic counseling • health care issues • work-out adaptation

16. Practical Management Points • CONTROVERSIAL !!! ??? • Screen all athletes • Acclimation • Modify drills • exclude from participation in performance tests such as mile runs, serial sprints, etc… • no repeat sprints beyond 500 meters without recovery period • no all-out exertion sustained 2-3 minutes without recovery period • extended recovery periods between bouts of exercise • Hydrate: dehydration fosters sickling • Set the tone • athlete should feel comfortable in reporting symptoms • coaches and medical staff should recogninize S&S • Performance levels increase with these changes

17. Sickle Cell Trait:Medical Problems • inability to concentrate urine normally • blood in the urine • spleen problems especially at high altitudes • exercise related rhabdomyolysis • exercise associated sudden death

18. Warning Signs • Leg pain • Back pain • Hematuria • Dehydration • Fatigue • A positive SCT test • When in doubt…..

19. Sickling CollapseSickling often confused with heat cramping; however, there are key distinctions • Heat cramping often has a prodrome of muscle twinges; whereas, sickling has none • The pain is different – heat-cramping pain is more excruciating • What stops the athlete is different – heat crampers hobble to a halt with “locked-up” muscles, while sickling players slump to the ground with weak muscles • Physical findings are different – heat crampers writhe and yell in pain, with muscles visibly contracted and rock-hard; whereas, sicklers lie fairly still, not yelling in pain, with muscles that look and feel normal • The response is different – sickling players caught early and treated right recover faster than players with major heat cramping

20. Sickle Cell Trait Review • PREVENTIVE MEASURES • prevent dehydration • medical issues • change conditioning protocol • medical history • take a stance

21. Medical History Questions • Do any of your close relatives suffer from SCD or SCT? • Have you ever been tested for SCT? • If yes, was the test positive? • If yes, what have you done differently? • Do you fatigue more than your peers in aerobic related activities? • If yes, explain? • Have you ever selectively opted out of a sport or activity because of fatigue? • If yes, explain why and list the types of symptoms that you have had during these situations.

22. Collapsed Athlete Case Study • Missouri linebacker Aaron O'Neal died July 12, 2005 after collapsing during a voluntary workout. The cause of death to this day is still debated.

23. References • Bergeron, M.F., J.G. Cannon, E.L. Hall, and A. Kutlar (2004). Erythrocyte sickling during exercise and thermal stress. Clin. J. Sport Med. 14:354-356. • Bile, A., D. Le Gallais, B. Mercier, P. Martinez, S. Ahmaidi, and Ch. Prefaut (1996). Anaerobic exercise components during the force-velocity test in sickle cell trait. Int. J. Sports Med. 17:254-258. • Bile, A., D. Le Gallais, B. Mercier, P. Martinez, A. Said, Ch. Prefaut, and J. Mercier (1998). Blood lactate concentrations during incremental exercise in subjects with sickle cell trait. Med. Sci. Sports Exerc. 30:649-654.Kark JA, Ward FT. Exercise and hemoglobin S. Semin Hematol 1994; 31:181-225. • Connes, P., F. Sara, M. D. Hardy-Dessources, L. Marlin, F. Etienne, L.Larifl a, C. Saint-Martin, and O. Hue (2006c). Effects of short supramaximal exercise on hemorheology in sickle cell trait carriers. Eur. J. Appl. Physiol.97:143-150. • Eichner, E. R. (1993). Sickle cell trait, heroic exercise, and fatal collapse. Phys. Sportsmed. 21(7):51-65. • Gardner, J. W., and J. A. Kark (1994). Fatal rhabdomyolysis presenting as mild heat illness in military training. Milit. Med. 159:160-163. • Jones, S. R., R. A. Binder, and E. M. Donowho, Jr. (1970). Sudden death in sickle-cell trait. N. Engl. J. Med. 282:323-325. • Kark JA, Posey DM, Schumacher HR, Ruehle CJ. Sickle cell trait as a risk factor for sudden death in physical training. N Engl J Med 1987; 317: 781-7. • Marlin, L., M. Etienne-Julan, D. Le Gallais, and O. Hue (2005). Sickle cell trait in French West Indian elite sprint athletes. Int. J. Sports Med. 26:622-625.

24. Sickle Cell Information Center • www.scinfo.org