Exercise and Collapse: Differential Diagnosis

Ken Taylor MDUCSD Sports Medicine

Diff Dx:Collapse during/after an endurance event

EAC EAH Heat exhaustion/Stroke Dehydration Exercise associated

hypoglycemia CVD: MI or Arrythmia

In the majority of cases no clear cut diagnosis is apparent

Exercise Associated Collapse

Most common disorders in MASH tent

EAC is not a diagnosis Inability to stand or walk

unaided as a result of Light-headedness Dizziness Syncope

Most symptoms resolve in the recumbent position!

Exercise Associated CollapseEpidemiology of EAC 85% of collapse after

finish line Why is cessation of

exercise an essential factor in EAC?

EAC: Rate of identifiable medical condition before finish line vs. after? 100% vs. 34%

Etiology of EAC Transient postural hypotension

Cardiac Output blood pooling in legs

Low peripheral resistance from compliant leg veins

Cessation muscle pump venous return

Forgotten Barcroft/Edholm reflex Drop Right Atrial Pressure Drop

peripheral resistance w/o increase HRorthostatic hypotension

Postural hypotension often severe ultra marathon/endurance unrelated to dehydration

Therapy of EAC

IV therapy not rational May induce iatrogenic

hyponatremia and hypoglycemia

Can be life threatening! Therapy aims to return blood

from periphery Keep walking after finish line! Elevate pelvis and legs Anti-histamines for recurrent

EAC? Failure to respond may

indicate (order of incidence) Hyponatremia Dehydration Heat Illness MI=incidence 1.2/100,000

marathon runners

Heat Illness SpectrumsHeat Exhaustion

Patients with EAC in extreme heat

Poorly defined syndrome which limits the ability to sustain exercise

Easily treated and resolves without sequelae

Presumed etiology ↓ fluids/electrolytes

Associated with moderate hyperthermia

Heat Stroke

CNS dysfunction Severe illness which may

result in death despite aggressive Rx

End organ damage and mental status changes

Definition of Exercise Associated Hyponatremia

Hyponatremia during or after exercise Moderate <

135mmol/L Severe < 130

mmol/L (<125)

History-EAH 1981

1st case: 2 runners participating in a 90-km race in South Africa.

1985 Hawaiian Ironman 29%

Shorter events? hikers in the Grand Canyon

1999 Marathon runners

Dogs

Noakes TD, Goodwin N, Rayner BL, Branken T, Taylor RK: Water intoxication: A possible complication during endurance exercise. Med Sci Sports Exerc17 :370– 375,1985

Symptoms with EAH? Asymptomatic in many disease states

The severity of neurologic symptoms correlates with rapidity & severity of

the drop in Na A gradual drop over days to weeks,

even to very low levels, may be tolerated, because of neuronal adaptation

Incidence of Exercise Associated Hyponatremia 1985 Hawaiian Ironman

29% of race finishers 1996 New Zealand Ironman

9% of athletes requiring medical care 1997 New Zealand Ironman

18% of race finishers 1997 Grand Canyon Study

6% of hikers requesting medical assistance had Na <130 2005 Boston Marathon

> 13% of finishers had a Na <135 2006 London Marathon

12.5% Asx Hyponatremic Racers: drank more (almost double) & gained more weight than non-hyponatremic racers

Questions?

Are there particular symptoms that help to differentiate hyponatremia vs heat illness?

Common symptoms N & V, Headache,

dizziness? No difference!

Distinguishing Hyponatremia vs Heat Exhaustion Hyponatremia

Tight watch Desire to urinate Weight gain

Should lose 1Kg+ body weight in standard Marathon

Seizures and change of mental status distinguished hyponatremia (P= 0.0002)

Seizures, combativeness or major confusion (71%)

Mild degrees of confusion and ↓coordination (100%)

Hyperthermia Tachycardia, hypotension &

orthostatic vital signs >50% of Heat exhaustion pts

were orthostatic 0% hyponatremia patients

Syncope 23% of heat exhaustion 0% of hyponatremic pts

Hyponatremia among Runners in the Boston Marathon NEJM April 2005

+ univariate analyses substantial weight gain consumption of more than 3 liters of fluids

during the race consumption of fluids every mile a racing time of >4:00 hours female sex low body-mass index.

+ multivariate analysis weight gain (odds ratio, 4.2; 95 percent

confidence interval, 2.2 to 8.2) a racing time of >4:00 hours (odds ratio

for the comparison with a time of <3:30 hours, 7.4; 95 percent confidence interval, 2.9 to 23.1)

body-mass-index extremes

488 runners /13% Na <135 / 0.6% Na <120

Summary: Risk Factors

Exercise duration >4 h or slow running/exercise pace Female gender (partly explained by lower body weight) Low body weight (also extremes of BMI) Excessive drinking (>1.5 L/h) during the event Pre-exercise over-hydration Post-exercise over-hydration Abundant availability of drinking fluids at the event Nonsteroidal anti-inflammatory drugs (not all studies) Extreme hot or cold environment

2005 Consensus panel treatment

Mild 130-135: fluid restriction and observe Severe <120 or symptomatic <130

Hypertonic saline Rapid correction, 100ml of 3% saline over

10min

References Almond et al. Hyponatremia among Runners in the Boston Marathon. N Engl J Med

2005 352: 1550-1556 Noakes TD et al. The incidence of hyponatremia during prolonged ultra endurance

exercise. Med Sci Sports Excer 1990;22:165-70. Backer HD et al. Exertional heat illness and hyponatremia in hikers. Am J Emerg

Med. 1999 Oct;17(6):532-9 Speedy D, Noakes T, Rogers I, Thompson J, Campbell R, Kuttner J, et al.

Hyponatremia in ultra distance triathletes. Med Sci Sports Exerc 1999;31:809-15 Ayus JC, Varon J, Arieff AI. Hyponatremia, cerebral edema, and noncardiogenic

pulmonary edema in marathon runners. Ann Intern Med 2000;132 :711– 714 Hew-Butler T, Almond C, Ayus JC, et al. Consensus statement of the 1st

International Exercise-Associated Hyponatremia Consensus Development Conference, Cape Town, South Africa 2005. Clin J Sport Med. Jul 2005;15(4):208-13

Kipps et al. The incidence of exercise-associated hyponatraemia in the London marathon. BR J Sports Med 2011;45:14-19

Asplund CA, O”Connor FG, Noakes TD. Exercise-associated collapse: an evidence-based review and primer for clinicians. BR J Sports Med 2011;45:1157-1162