Case Study: Nauseous in the Heat

By Tod Schimelpfenig

Jul 22, 2021

Three people shade and fan an individual sitting on the ground in a hot, sunny field
Photo by Kirk Rasmussen.

The Setting

You and three friends have been hiking 18-20 miles a day for three days in the U.S.'s desert southwest. It’s been hard and hot, as anticipated. You’ve found water every day.

This afternoon you backpacked over a steep, sun-drenched sandstone ridge and down into a cottonwood glade. One of your companions has been lagging behind and eventually stops and sits by the side of the trail. He is sweaty and says he feels awful.

Your scene size up is brief; no hazards, one patient who looks sick and sat down.

You think about BSI (body substance isolation) but keep your limited glove supply in your first aid kit for now. The patient agrees to your assessment; he has a sound airway, is breathing without distress, is dressed in only shorts and t-shirt, is obviously not bleeding, has a strong radial pulse and is on dry ground in the shade on a nice warm day.

SOAP Report

Subjective

The patient is a 24-year-old male who states he “feels lousy.” He has been backpacking long distances for three days in hot weather (highs in the low 90’s F) and this afternoon became too weak to hike.

Objective

Patient Exam

Patient sat down by the side of the trail. There is no mechanism for injury. No obvious injuries were found in a head-to-toe assessment. Patient is sweating. Skin is not hot to the touch and the patient has a normal mental status.

Vital Signs

Time

13:00

Level of Responsiveness (LOR)

A+OX4

Heart Rate (HR)

100, strong, regular

Respiratory Rate (RR)

18, regular, easy

Skin Color, Temperature, Moisture (SCTM)

Pink mucous membranes, warm and moist

Blood Pressure (BP)

Strong radial and pedal pulse

Pupils

PERRL

Temperature (T°)

Not taken

History

Symptoms

Patient states he is dizzy, nauseous and “feels lousy”

Allergies

None stated

Medications

Occasional ibuprofen at 400-600mg for muscle soreness during the hike, none taken today

Pertinent Hx

Patient denies any ongoing medical conditions.

Last in/out

Patient drank 3 liters of fluid so far today, ate breakfast and ongoing trail snacks, urinated a light yellow urine twice today and stated this is normal on long hikes. He had a normal bowel movement this morning. Denies recent diarrhea or vomiting.

Events

Patient has been hiking in hot, dry weather for three days, 18-20 miles per day without problems. He has not fallen or suffered any injuries.

STOP READING!

What is your assessment and plan? Take a few minutes to figure out your own assessment and make a plan. Don’t cheat—no reading on without answering this first!

Three backpackers in the desert
Photo by Matt Hage

Assessment

  • Possible heat illness/exhaustion. Normal mental status suggests heat stroke is unlikely.
  • Possible flu-like illness

Plan

  • Rest in shade and repeat assessment: carefully exploring hydration history.
  • Have patient drink fluids and eat salty snacks, monitor urine output
  • Make a decision on continuing hike or evacuation based on patient condition.

Anticipated problems

Patient does not improve and we have to evacuate.

Comments: Vague Symptoms

The vague complaint of “feel lousy” could be any number of things, although the environment makes you think of heat and hydration problems. The head-to-toe didn’t reveal any obvious abnormalities.

As you’ve been with this person for three days and you’ve all been diligent about hydration, you’re considering that they should not be under or over-hydrated. They look like they could be sick, but this came on suddenly and your group has been healthy on the hike. It’s low enough that altitude illness is not high on your list of possibilities, nor is a hangover. The patient is not diabetic and seems to have been eating well, so blood sugar abnormalities are not obvious.

You considered a worst case scenario of heat stroke, but note the normal mental status. Your plan is to explore the hydration history again.

Assuming he is well hydrated without confirming intake and output can lead to poor decisions and treatment plans. Three liters might be too little today—plus, dehydration can be cumulative over several days. Since there are no obvious evacuation triggers, you decide to monitor the patient to see if he gets better or worse.

The Tale Continues

Vitals

Time

13:00

13:30

14:00

14:30

Level of Responsiveness (LOR)

A+OX4

A+OX4

A+OX4

A+OX4

Heart Rate (HR)

100, strong, regular

100, strong, regular

84, strong, regular

76, strong, regular

Respiratory Rate (RR)

18, regular, easy

16, regular, easy

14, regular, easy

14, regular, easy

Skin Color, Temperature, Moisture (SCTM)

Pink mucous membranes, warm and moist

Pink mucous membranes, warm and moist

Mucous membranes pink, skin warm, dry

Mucous membranes pink, skin warm, dry

Blood Pressure (BP)

Strong radial and pedal pulse

Strong radial and pedal pulse

Strong radial and pedal pulse

Strong radial and pedal pulse

Pupils

PERRL

PERRL

PERRL

PERRL

Temperature (T°)

Not taken

Not taken

Not taken

Not taken

Sample History

Symptoms

As the afternoon progressed the patient felt better, although still tired and low on energy. Denies headache. Mental status remains normal.

Allergies

Patient continued to deny allergy.

Medications

Patient re-stated only occasional ibuprofen use and none today.

Pertinent Hx

Patient denies any ongoing medical conditions.

Last in/out

Patient has been drinking 5-6 liters of fluid daily for the past three days and eating regular meals and snacks. He states his urine volume and color have been normal for him.

Events

Patient denies recent illness and says he has been feeling fine.

Assessment

  • Possible heat exhaustion. Normal mental status suggests heat stroke is unlikely.
  • Possible flu-like illness.

Plan

  • Rest in shade and stop here for the night.
  • Have patient drink fluids and eat salty snacks, monitor urine output
  • Make a decision in the morning on continuing hike or evac based on patient condition.

Anticipated problems

Patient does not improve.

Comments on Leadership in Wilderness Medicine

Wilderness medicine is commonly low drama and routine problems; flu-like illness, mild/moderate stages of environmental problems, sore muscles, minor cuts and scrapes. Early intervention keeps these minor problems from becoming significant concerns. So much of sound wilderness medicine is also sound outdoor leadership.

When there is nothing obviously dire in the patient’s presentation, we consider the worst case, see if we can rule anything out, treat for multiple problems, and see if the patient gets better or worse. A worst case would be heat stroke, which is not apparent in this patient whose skin is not hot and who has normal mental status. The hydration history suggests that hyponatremia from drinking too much, or dehydration from drinking too little, are both unlikely.

Trends in Vital Signs are Vital to Assess

The first set of vitals establishes a baseline. Changes, or stability, are both important pieces of information. In this case the vital sign trend tells us the patient is stable and even improving. A heart rate that stays elevated or trends faster, with pale moist skin and perhaps a weakening radial pulse or altered mental status tells us something is going on, perhaps some form of shock. A patient who continues to complain of being weak and feeling ill is obviously not improving.

Maybe this is just a mild flu-like illness, low blood sugar, or fatigue from the heat. We often treat for multiple problems at the same time, throwing a wide net over the problem. Heat stress and possible dehydration are managed by seeking shade, resting and supporting hydration, which also treats a possible flu-like illness. If our net doesn’t help the patient get better, we evacuate.

End of the Tale

The patient felt much better within a few hours and wanted to get on down the trail, but the group decided to move only a short distance to a nicer campsite for the night. In the morning the patient, well hydrated, rested and fed, was able to resume the hike.

Patience with our patients is a virtue in wilderness medicine. We want to fix problems quickly, yet we often get ill slowly, and better slowly.

One of the traps of the short scenarios common in wilderness medicine courses is the illusion that people get better quickly. People may be physically in wilderness, but often act like they are in a city, with expectations for quick solutions to inconveniences, let alone real problems. This group acted as if they were in the wilderness. They changed their plans, stopped the hike, and rested and cared for their companion.

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Written By

Tod Schimelpfenig

As a NOLS Instructor since 1973 and a WEMT, volunteer EMT on ambulance and search and rescue squads since the 70s, Tod Schimelpfenig has extensive experience with wilderness risk management. He has used this valuable experience to conduct safety reviews as well as serve as the NOLS Risk Management Director for eight years, the NOLS Rocky Mountain Director for six years, and three years on the board of directors of the Wilderness Medical Society, where he received the WMS Warren Bowman Award for lifetime contribution to the field of wilderness medicine. Tod is the founder of the Wilderness Risk Manager’s Committee, has spoken at numerous conferences on pre-hospital and wilderness medicine, including the Australian National Conference on Risk Management in Outdoor Recreation, and has taught wilderness medicine around the world. He has written numerous articles on educational program, risk management and wilderness medicine topics, and currently reviews articles for the Journal of Wilderness and Environmental Medicine. Additionally, he is the author of NOLS Wilderness Medicine and co-author of Risk Management for Outdoor Leaders, as well as multiple articles regarding wilderness medicine. Tod is currently the Curriculum Director of NOLS Wilderness Medicine.

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