This course is designed to introduce you to the most common and most important conditions you’ll be treating in the medical tent.

1. Marathon Medicine
Medical Volunteer 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 Collapse
Presentation
• 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. Exertional Hyponatremia
• 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

11. Exertional Hyponatremia
Treatment
• 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

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 Illness
Definitions – 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. 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

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 Illness
On-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
• 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

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!