Case Study 35

The Answer


Possible heat and/or hydration problem.

  • Heat stroke: Heat stroke is a concern but the patient’s temperature and absence of obvious altered mental status rule it out for the time being.
  • Heat Exhaustion/dehydration: This is possible but lack of thirst, history of water intake, and clear urine argue against this.
  • Over-Hydration/hyponatremia: This is possible. Cumulative water intake, lack of food, and swollen fingers argue for over-hydration. The absence of obvious altered mental status suggests this is mild to moderate over-hydration.

The Plan

  • Move patient onto pad and off the hot ground. Keep her resting in the shade. Sponge her with water to cool.
  • Two people will hike to nearest water (two-hour round trip) and refill all containers (we have three-gallon capacity).
  • Two people will hike to top of ridge for attempted cell phone contact.
  • Restrict water intake and try to get patient to eat salty snacks. Monitor condition with a focus on mental status and temperature. 
  • Gather the group together after water and cell phone parties return and assess and revise plan as needed.

Anticipated Problems

  • Development of heat stroke. 
  • Lack of resolution of the present problem and continued inability of the patient to travel.


This is not an easy assessment. The overlap of vague and non-distinguishing symptoms can make differentiating over-hydration/hyponatremia from dehydration, heat exhaustion, or heat stroke challenging. Imagine how much more difficult this would be if the thermometer was not available (is this heat stroke?) or the mental status was abnormal (is this heat stroke or serious over-hydration/hyponatremia?).

Over-hydration/hyponatremia mistaken as dehydration or heat exhaustion and treated with fluid intake can exacerbate the over-hydration/hyponatremia. Indeed, there are case reports of this very scenario happening in the field when well-intentioned companions encouraged over-hydrated patients to “hydrate or die” and when over-zealous ambulance crews administered unneeded IV fluids. 

The cautious treatment approach of these folks, in a patient who was ill but who did not have any immediate life threats, was based on an understanding that incorrectly treating over-hydration/hyponatremia with fluid is more dangerous than delaying treatment of dehydration. They followed current recommendations by restricting fluid and adding salty snacks while they waited for the patient to urinate excess fluid. Salt snacks are OK.  Concentrated oral salt solutions have been shown to elevate serum sodium concentration when treating mild/moderate hyponatremia with fluid restriction. Bouillon cubes (2 in 100 mL water provides 80 mEq sodium) are effective and have been used in the backcountry. Be careful not to induce nausea and vomiting.

End of the Tale

The water team returned with two gallons. The cell phone team was unable to make contact, but spotted a well-used two track in a nearby wash. In the meantime, the patient began to urinate copiously. A few hours later, she was still weak but able to stand. 

The group stayed hydrated, rested, and ate through the afternoon. Eventually the patient said she was thirsty and began to drink water spiked with some salt. In the cool of the evening the group walked slowly with the patient to the two track when, with a stroke of luck, they ran into a fellow on a dirt bike who was able to head to a parking lot and return with an ATV and give the patient and her companion a ride to town.