Medical Volunteer Training by Ben Nelson, MD Grandma's Marathon Medical Director

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!