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Marathon Medicine Medical Volunteer Training Course Ben Nelson MD Essentia Health Sports Medicine Grandma’s Marathon

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Marathon MedicineMedical Volunteer Training Course

Ben Nelson MD

Essentia Health Sports Medicine

Grandma’s Marathon

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

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

Exercise Associated CollapsePresentation

• Runners with EAC will be exhausted, lightheaded, unsteady on their feet or unable to stand

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

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.

Exertional Hyponatremia

• Risk factors– Finishing time over 4 hours

– Marathon running inexperience– Small stature– Female gender– NSAID use– Unusually hot conditions

Exertional Hyponatremia

• Mild EH• Defined by Na+ less

than 135mmol/L with headache, parestesias, 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 HyponatremiaTreatment

• 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

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

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

– Exertional Heat Stroke – Hyperthermia with central nervous system changes (Mental Status Changes) and possibly multiple organ system failure

Heat-Related Illness

• 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

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!!!

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

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

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

Time to defibrillation affects survivalSurvival rate decreases by 10% every 3 minutes in VF

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 should not be 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.

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.

Stress Fractures: Diagnosis

• Physical exam: Reproducible focal point tenderness. Pain with ROM if joint involved (ie femoral neck)

• Imaging: – X-rays could reveal evidence of healing stress

fracture or completed stress fracture.– MRIs image of choice given high

sensitivity/specificity and ability to assess soft tissues.

– CT and bone scans are slightly inferior alternatives to MRI.

High Risk Stress Fractures

• 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– Accult fractures.

• High Risk Locations– Femoral Neck– Tibial Diaphysis– Navicular– 5th Metatarsal Diaphysis

Thank You!