Heat Illnesses--Heat Cramps, Heat Exhaustion, and Heatstroke

Disclaimer.  I am not a licensed health practitioner.  This is just another post on knowledge and understanding you might wish to acquire in advance of a disaster in case no higher care is available.  As long as our society is functioning, you should leave anything more substantial than applying a Band-Aid to the professionals.  No medication, including those available over the counter, should be taken without consulting a physician.  Information shared here is for educational and entertainment purposes only.  It is not medical advice nor a substitute for licensed medical care. 


Heat illnesses run along a spectrum ranging from heat stress, where a person is just uncomfortable, to heat exhaustion where physiological problems are setting in, to heatstroke which can become fatal.  Knowing the risk factors and causes as well as preventative measures will help avoid problems when the temperatures rise.

Heat edema is temperature-induced swelling that may occur in the extremities.  The treatment is to elevate the limbs affected whenever possible.  The swelling may persist for weeks.

Heat cramps generally occur in people working hard in hot temperatures, but children may also experience these as a result of running around and playing in extreme heat.  And it can even occur in overdressed skiers in winter if they aren't rehydrating.  The muscle spasms can be quite painful and usually only affect the arms and legs, but sometimes abdominal muscles are also involved.  The person should be directed to lie down in a cool area.  Treatment consists of administering oral rehydration salts or a teaspoon of salt in a quart of water.  In addition, massaging the painful muscles will help relieve the soreness.  The body temperature is normal and the patient is fully conscious. 
 
Heat exhaustion is acute heat injury due to dehydration and usually is accompanied by hyperthermia.  The body can no longer dissipate the heat adequately as a result of extreme environmental conditions.  The patient may be pale, weak, and nauseous, with cool, moist skin.  Symptoms may include headache, dizziness, loss of appetite, and vomiting.  The pupils may be dilated and the patient will have a weak, rapid pulse and rapid, shallow breathing.  The mental status is normal, and the patient may have a fever of up to 103.5 degrees.   The treatment is to have the patient lie down and elevate the feet above the heart.  Oral rehydration solution or saltwater, one teaspoon of salt per quart of water, should be administered hourly.  If the patient is unable to drink, fluids may be administered intravenously, rectally, or subcutaneously. 

Heatstroke sets in when the heat-regulating mechanisms in the brain fail.  This is a medical emergency and treatment by a licensed provider must be sought out if at all possible.   And it can occur even if the patient hasn't been in the sun.  It can happen with the young and old in hot temperatures in the shade, and especially in those with underlying illnesses.  It is often referred to as classic heatstroke.  It is the underlying disease that is triggering the body's response.  Exertional heatstroke occurs in younger people exercising in the heat.

Regardless of the cause, the treatment is the same.  The skin is usually red, very hot, and dry (not even the armpits are moist), though not always, and that is why the temperature must be taken.  If the core body temperature is above 104 degrees, heatstroke may occur without rapid treatment.  The pupils are dilated and there is generally headache, confusion, and loss of consciousness.  Seizures and blood in the urine or vomit may also occur. 

The treatment for all heat illnesses is to remove the patient from the hot environment to a cool and shady place.  Clothing should be removed and cold, wet sheets placed on the skin with fans blowing to cool the body.  Ice packs should be placed in the groin, armpits, and neck.  (Instant cold packs are not effective in this situation.)  Intravenous fluids administered by a licensed professional would be best, but fluids given orally (if the patient is conscious) or rectally or subcutaneously are acceptable options.

Unlike with hypothermia where body temperature should be restored to normal gradually, with heatstroke the body temperature must be reduced below 104 degrees as rapidly as possible.  Note that acetaminophen and ibuprofen will not work to lower the body temperature in cases of heatstroke; those medications only lower fevers due to an infection.

Those at greatest risk for developing heat-related illnesses are:

• Alcoholics
• Elderly (some say anyone over the age of fifty)
• Infants and small children
• Obese individuals
• Those taking medications such as diuretics, anticholinergics, or under the influence of drugs

Risk factors may be mitigated by dressing appropriately for the weather and avoiding dehydration and physical exertion in hot temperatures.

Links to related posts:
Oral Rehydration Salts
Instant Cold Packs  

For further reading:
Survival and Austere Medicine, 3rd Edition, pp 193-194.
Dr. Joseph Alton, The Survival Medicine Handbook, pp 204-07.
David Werner, Where There Is No Doctor, p 81.

 6 may 2020