Hyperthermia

HYPERTHERMIA: Heat Related Illness

THE HAZARDOUS EFFECTS OF HEAT AND HUMIDITY ON THE ELDERLY
Summer has finally arrived in Michigan, but is your home prepared to handle its effects? Soaring temperatures and high humidity can drain healthy young people, but it is an especially serious combination for our elderly and physically compromised residents. If not managed effectively, it can lead to unnecessary suffering and even death.

So let's take a closer look at what happens when temperatures rise and the weather is muggy. What can you do to help KEEP COOL?

Just what is HYPERTHERMIA?
Hyperthermia is defined as an abnormally high body temperature caused by inadequate or inappropriate responses of heat-regulating mechanisms (Merck Manual of Geriatrics 3rd edition, 2000).

Inadequate or Inappropriate Responses of Heat-regulating Mechanisms?
Most of us lose body heat through evaporation from skin and lungs and by endocrine and autonomic responses that cause blood vessels to dilate and cardiac output, heart rate and sweating to increase, thus moving more heat from the body. Heat is lost because it can transfer from the warmer body to a cooler environmental temperature. When the environment is hotter than the body temperature or the humidity is too high, these mechanisms can fail and the heat remains in the body, causing body temperature to rise.

Certain risk factors related to age or compromised physical condition can affect the heat-regulating mechanisms.

Risk Factors include:

  • Poor circulation, inefficient sweat glands, and changes in the skin caused by the normal aging process
  • Heart, lung and kidney diseases, as well as any illness that causes general weakness or fever
  • High blood pressure
  • The inability to perspire, caused by medications including drugs with anticholinergic effects such as diuretics, sedatives, anti-depressants, and tranquilizers, anti-parkinsonian medications, antihistamines, and certain heart and blood pressure drugs, such as beta-blockers
  • Taking several drugs for various conditions
  • Conditions that require a change in diet
  • Drinking alcoholic beverages
  • Being substantially overweight or underweight

Other Risk Factors include:

  • Unbearably hot living quarters
  • Overdressing
  • Lack of adequate fluid intake
  • Lack of understanding of weather conditions

SYMPTOMS of hyperthermia include:
Headache, nausea, and fatigue after exposure to heat indicate some measure of a heat-related illness. The two most common forms of hyperthermia are HEAT EXHAUSTION and HEAT STROKE .

HEAT EXHAUSTION:

  • Loss of appetite
  • Nausea
  • Vomiting
  • Disorientation
  • Postural hypotension
  • Cramping may occur
  • Body temperature normal or elevated
  • May be thirsty and weak
  • May be light-headed, dizzy, or lose consciousness

HEAT STROKE

HEAT STROKE IS A LIFE THREATENING CONDITION. MEDICAL ATTENTION IS IMMEDIATELY NECESSARY.

  • Dangerously high body temperature
  • Absence of sweating; dry flushed skin
  • Severe central nervous system disturbance
    • May have experienced transient light-headedness, dizziness, headache, weakness, shortness of breath or difficulty breathing and nausea
    • Combativeness
    • Bizarre behavior
    • Staggering
    • May convulse
    • Loss of consciousness
  • Lethargy, stupor or coma
  • Slow, thready pulse or strong, rapid pulse
  • Blood pressure may be low or difficult to hear/palpate
  • Cardiac abnormalities
  • Metabolic acidosis
  • Respiratory alkalosis
  • Severely low potassium levels

SO WHAT SHOULD WE DO TO KEEP COOL AND TO PREVENT HEAT-RELATED ILLNESSES FROM BECOMING A SERIOUS PROBLEM?
Follow the Recommendations To Health Facilities For Handling Heat And Humidity In Summer Months; (5/23/05 Michigan Department of Licensing & Regulatory Affairs notification to long term care facilities)

The Notification recommends:

  • Keep the air circulating
  • Draw all shades, blinds, and curtains in rooms when exposed to direct sunlight
  • Remove residents from areas that are exposed to direct sunlight
  • Keep outdoor activities to a minimum
  • Check to see that residents are appropriately dressed
  • Provide ample fluids
  • Increase the number of baths given

Other recommendations include:

  • Wear a hat outdoors
  • Wear loose clothing of natural fabric, such as cotton
  • Sponge with wet cold cloths
  • Avoid hot, heavy meals, caffeine and sugary drinks
  • Open windows at night
  • Remain indoors in hot, humid weather or on ozone action days and days with air pollution alerts in effect
  • Plan rest periods

REFERENCES

The Merck Manual of Geriatrics, 3rd edition

National Institute on Aging Fact Sheet: Hyperthermia: A Hot Weather Hazard for Older People

Michigan Department of Licensing & Regulatory Affairs, Bureau of Community and Health Systems, Health Facilities Division's Notification: Recommendations To Health Facilities For Handling Heat And Humidity In Summer Months (5/23/05)