Marathon Maladies & Dehydration Debunked
Hyponatremia, or overhydration, can be lethal if treating as a case of dehydration.
Patients who are displaying signs of CNS dysfunction in the presence of hyperthermia and are so presumed to be suffering a heatstroke need urgent care. As with all conditions, ABCs must be evaluated and serially reassessed. One of the dangers in heatstroke is the patients' loss of ability to maintain their own airway, as well as seizure activity. The tonic-clonic activity in seizures produces even more heat, of which the body cannot rid itself. This is a true heat emergency; rapid cooling is the rule. Evaporative cooling via spraying water on the patient's skin and having it fanned off, in addition to placing cold packs in the patient's groin, axilla and on both sides of the neck, has been shown to be a very effective method in the prehospital setting. Airway control measures and oxygen administration as dictated by protocol are indicated, but vigilance is important and constant reassessment is essential, as the heatstroke patient's condition can deteriorate in a matter of seconds. As there is no evidence that heatstroke is caused by dehydration, minimal (TKO/KVO) intravenous fluids should be administered, unless otherwise dictated by other processes, protocol or medical control.
Exertional hyponatremia should be considered in the patient who:
- presents with CNS dysfunction
- has been participating in strenuous or endurance activities
- is not hyperthermic
- has no evidence of trauma
- has no evidence of hypoglycemia.
In addition to monitoring ABCs, prehospital treatment consists of intravenous normal saline (0.9%) administration. You should now be able to go back and see why IV D5W actually worsened the patient's condition. The patient's sodium level decreased as a result of her overhydration by drinking too much water. Administration of a solution like D5W, which is mostly free water, exacerbates the patient's fluid overload and even further dilutes the sodium level in the blood. Some authorities advocate using intravenous hypertonic (3%) saline for the severe hyponatremia patient, but this consideration is being excluded because most prehospital agencies do not readily stock hypertonic intravenous fluids. Intravenous furosemide is also indicated to ensure excess water is rapidly excreted. In-hospital treatment consists of a full assessment of the patient's sodium and fluid status and proper replenishment in a controlled setting with serial reassessment.
While a thorough medical history is always important, it is vital to ask athletic competitors about their intake of medications, both prescription and nonprescription. Pay particular attention and document the use of diuretics, muscle-builders, fat-burners, appetite-suppressants, creatine, etc., as they may have affected the patient's metabolic status.
The purpose of this article is to remind field providers that not all calls on hot days are simple heat exhaustion or dehydration, as well as to advise providers that there is active debate and research into exercise-related and heat-related illnesses. Emergency medical services, like all areas of medicine, are constantly being researched, challenged and evaluated. All providers are reminded that they must follow the protocols established by their EMS agency.
Learning Point
The literature suggests that females are affected by hyponatremia more than males, and that the less-competitive athlete (toward the back of the race) is affected more than the competitive athlete. A study by Runner's World indicated that 74% of runners take analgesics and more than 88% report using NSAIDs (non-steroidal anti-inflammatory drugs), including naproxen sodium (Naprosyn) and ibuprofen (Advil).4 NSAIDs seem to increase the risk, probably because the drugs impair the body's ability to excrete water. The seven runners who died from hyponatremia all had a history of NSAID use. In fact, Tylenol is a sponsor of the ING NYC Marathon and is the only approved anti-inflammatory agent for distribution by the marathon medical staff because it does not pose this risk. It should be noted that some physicians may not be aware of NSAIDs' effect on the kidneys, especially if they are not sports-oriented physicians, and may be misadvising athletes to take NSAIDs prior to endurance activities.
Learning Point
According to the National Oceanic and Atmospheric Administration (NOAA), approximately 175¡V200 persons die from heat-related disorders during an average year in the United States. This statistic rises to more than 1,500 persons during heat waves. The exact number of persons seeking treatment for heat-related disorders is not recorded but reaches the thousands. Estimates of fatalities caused by heat-related illness in the United States range from 300 to several thousand per year. The mortality rate in patients with heatstroke has been reported to be 10%¡V70%, with the highest number of deaths occurring when treatment is delayed for more than two hours.
Heat waves increase the mortality rate. The heat wave in July 1995 caused 91 deaths in Milwaukee and 465 deaths in Chicago.
