Marathon Medicine Medical Volunteer Training Course

1. Marathon MedicineMedicalVolunteer Training Course Ben Nelson MD Essentia Health Sports Medicine Grandma’s Marathon

2. Introduction • Thank you very much for volunteering to provide medical coverage at Grandma’s Marathon. • This course is designed to introduce you to the most common and most important conditions you’ll be treating in the medical tent. • These issues include: • Exercise Associated Collapse • Heat-Related Illness • Exertional Hyponatremia • Cardiac Arrest • Stress Fracture

3. Exercise Associated Collapse • This is the most common medical problem encountered after marathons • 59-85% of all post-marathon medical visits • Br J Sports Med. 2011 Nov;45(14):1157-62. • EAC is caused by a postural drop in systolic blood pressure • Inactivation of the calf muscle pump upon cessation of prolonged exercise • Results in lower extremity venous blood pooling, reduced atrial filling pressure, and subsequent syncope

4. Exercise Associated CollapsePresentation • Runners with EAC will be exhausted, lightheaded, unsteady on their feet or unable to stand

5. Exercise Associated Collapse Treatment • Evaluate in supine position with legs elevated • Oral rehydration • Cooling • Rest • Most patients will recover in 30 min • Monitor for MENTAL STATUS CHANGES or failure to progress – which might suggest • Exertional Hyponatremia • Hyperthermia • Cardiac Arrest • Hypothermia • Hypoglycemia

6. True or False? • A patient with suspected exercise associated collapse is not improving despite 30 minutes of rest with her legs elevated, gentle cooling and oral fluids. You should give her a liter of IV normal saline.

7. False • It would be appropriate to check her core temperature (rectal thermometer) and serum electrolytes. • IV fluids are rarely necessary. Oral rehydration is safer and less expensive. • If the patient is too nauseated to tolerate oral fluids antiemetic medications are available.

8. Exertional Hyponatremia • Dilutional decrease in serum sodium concentration during physical activity caused by: • Over hydration • Salt losses in sweat • Fluid retention enhanced by increased ADH secretion during running • Incidence • 12.5% of marathon runners. • London Marathon • Br J Sports Med. 2011 Jan;45(1):14-9. Epub 2009 Jul 20.

9. Exertional Hyponatremia • Risk factors • Finishing time over 4 hours • Marathon running inexperience • Small stature • Female gender • NSAID use • Unusually hot conditions

10. Mild EH Defined by Na+ less than 135mmol/L with headache, paresthesias, nausea, bloated/swollen sensation Severe EH Defined by Na+ less than 135mmol/L with decreased mental status, confusion, disorientation, agitation, delirium, seizures, respiratory distress Exertional Hyponatremia

11. Mild EH No IV fluids Consider oral fluid restriction Pt may drink salty oral fluids like V8, Coke, or chicken broth (4 bouillon cubes in 4oz water). Monitor until urination. Discharge home with instructions to monitor for EH symptoms and to seek urgent medical attention if any symptoms develop Severe EH Check core temp – treat hyperthermia if present 100mL 3% hypertonic saline bolus Up to two additional 100ml 3% hypertonic saline boluses may be given at 10 min intervals with Na+ recheck and no improvement in symptoms Transfer to ER for ongoing treatment/monitoring/recovery Exertional HyponatremiaTreatment

12. True or False? • A runner with headache, nausea, and tingling feet has a Na+ 125. She has no confusion. She could receive 1L of IV normal saline.

13. False • No exercise-associated hyponatremic patient should receive IV normal saline. • Mild hyponatremics (those without mental status changes) can use saltly oral fluids until they urinate. • Severe hyponatremics (those with mental status changes) should receive the hypertonic saline boluses. • Please involve Dr. Nelson or Dr. Pipho in the care of any hyponatremic patients.

14. Heat-Related Illness • On a cool, dry day we’ll care for around 200 ill runners. On a hot, humid day the race could generate over 600 patients in the medical tent. • Heat-Related Illness can cause a mass-casualty event in hot or humid marathons • Heat-Related Illness can be life-threatening and must be identified and treated promptly

15. Heat-Related IllnessDefinitions – Continuum of disease • Hyperthermia – core temp > 40°C or 104°F • Heat Cramps – cramping assoc with dehydration, muscle fatigue, and electrolyte depletion. • Heat Exhaustion – Inability to exercise due to heat intolerance • Heat Stroke – Hyperthermia with central nervous system changes (Mental Status Changes) and possibly multiple organ system failure

16. Symptoms are Nonspecific Headache Dizziness Profound Fatigue Chills Nausea Vomiting Heat Cramps Signs Core Temp > 39.4 Tachycardia Hyperventilation Hypotension Syncope Disorientation Confusion Irrational/unusual behavior Heat-Related Illness

17. Treatment of Heat-Related Illness • Early recognition and treatment is key • Rectal Temp is the only accurate measure of core temperature • Emperical treatment if suspicion is high • Remove excess clothing • Place in supine position with legs elevated • Oral fluid replacement • Cooling therapy • Must be done on-site prior to transfer • Time is tissue!!!

18. Treatment of Heat-Related IllnessOn-Site Cooling Methods • Ice Bags • Place bags in groin, axilla, and behind neck • Least efficient but most convenient cooling method • Appropriate for low-grade cases • Iced Towels • Cover exposed skin with iced towels • Place fan on pt for improved convection • Proven as a rapid method for core temp reduction • Less invasive than Ice Water Submersion • Ice Water Submersion • Continuous rectal temperature must be monitored • Pt is lowered into ice water • Remove pt when temp is below 40C

19. True or False? • A hyperthermic runner with delirious behavior should be emergently transferred to the hospital for cooling.

20. False • Heat stroke needs to be treated immediately with on-site cooling in the medical tent. • Ice water submersion has the fastest core temp cooling rate, followed by iced towel rotation.

21. Cardiac Arrest • Incidence of SCA • 1 in 57,000 marathon runners • Retrospective survey of marathon medical directors • Med Sci Sports Exerc. 2012 Apr 19. • 1 per 100,00 full marathon runners • Race Associated Cardiac Arrest Event Registery • N Engl J Med. 2012 Jan 12;366(2):130-40 • 1 per 50,000 marathon runners • TCM and Marine Corp marathons 1976-1994 • J Am Coll Cardiol. 1996 Aug;28(2):428-31

22. Location of Cardiac Arrest According to Race Quartile. Cardiac Arrest Can Happen Anywhere on the Course.

23. Time to defibrillation affects survival Survival rate decreases by 10% every 3 minutes in VF

24. Myocardial Infarction • Most common in middle-aged male runners • May have vague or atypical presentation mimicking other conditions like GERD or MSK pain • A normal EKG in the medical tent is not reassuring as ischemic changes may have not yet developed • All angina should be considered unstable. Emergency cardiac meds and rapid hospital transfer should be initiated.

25. Stress Fractures • Atraumatic bone injury caused by repetitive, excessive stress. • Continued stress can progress to complete fractures. • Stress fractures comprise 5-10% of sports medicine visits in the US. • Running is the most common sport associated with stress fractures.

26. Stress Fractures • History: Focal bone pain worsened with walking, running or weight bearing. Pain may persist into rest periods. • Physical exam: Reproducible focal point tenderness. Pain with ROM if joint involved (ie femoral neck) • Urgency of treatment depends on low or high-risk stratification

27. High Risk Stress Fractures should be made non-wt bearing and sent for urgent imaging Increased risk complications including: Malunion Nonunion Avascular necrosis Arthritic change Occult fractures. High Risk Locations Femoral Neck Tibial Diaphysis Navicular 5th Metatarsal High Risk Stress Fractures

28. True or False • A runner has severe groin pain. You suspect a femoral neck stress fracture. This patient can be placed on crutches and follow-up with an orthopedists in 2 or 3 days.

29. False • Xrays should be done immediately to evaluate for a completed femoral neck stress fracture. This is urgent because of the risk of femoral head avascular necrosis and developing hip arthritis.

30. Thank You!