PETS AND PEOPLE

Heatstroke (Hyperthemia in Pets)

Posted

An increase in body temperature is called hyperthermia, commonly referred to as heatstroke.  Body temperature may be elevated because of an infection (fever), but it may also increase because of hot and/or humid conditions outside.  More frequently I see patients at the Manchester Animal Hospital who have been left in cars.

Symptoms of heatstroke are:

  • A dog’s normal body temperature is 101.5°F plus or minus 1 degree Fahrenheit, and any time the body temperature is higher than 105°F, a true emergency exists.  Heatstroke generally occurs in hot summer weather when dogs are left with inadequate ventilation in hot vehicles.  It may appear that appropriate ventilation is maintained with a small opening in the window (s).  This is not necessarily true. When left in a car on a relatively cool (70°F) day; a recent study from Stanford University Medical Center found the temperature within a vehicle may increase by an average of 40 degrees Fahrenheit within one (1) hour regardless of the outside temperature. 
  • Initially, the pet appears distressed and will pant excessively and become restless. As the hyperthermia progresses, the pet may drool large amounts of saliva from the nose and/or mouth. The pet may become unsteady on his feet. You may notice the gums turning blue/purple or bright red, which is due to inadequate oxygen.

 Below are some examples of how hot the interior of a car gets when the external temperature is warm to hot:

  • When the external temperature is 70 the internal temperature is  100
  • When the external temperature is 75 the internal temperature is  110
  • When the external temperature is 80 the internal temperature is  120
  • When the external temperature is 85 the internal temperature is  130
  • When the external temperature is 90 the internal temperature is  140 

Heatstroke may also occur in other conditions, including:

  • When an animal is left outdoors in hot/humid conditions without adequate shade.
  • When exercised in hot/humid weather.  

Other predisposing factors may be obesity and/or diseases affecting a pet’s airway.  Keep in mind that prolonged seizures, eclampsia (milk fever), poisonings, and many other conditions may cause hyperthermia.  Also, brachycephalic (short-nosed) breeds (Pekingese, Pug, Lhasa Apso, Boston terrier, etc.) may suffer from “ineffectual panter syndrome” which results in an increased body temperature that may be fatal.

What to Do: 

Beginning the process of cooling the pet immediately is extremely important. 

  • Remove your pet from the environment where the hyperthermia occurred. 
  • Move your pet to a shaded and cool environment and direct a fan on them.
  • If possible, determine rectal temperature and record it.
  • Place your pet in a cool or tepid water bath (or in the shower) without submerging their heads. 
  • You may also wet the ear flaps and paws with cool water. Directing a fan on these wetted areas will help to speed up evaporative cooling. Transport to the closest veterinary facility immediately.

What NOT to Do:

  • Do not over-cool the pet.  Do not cover your pet with wet towels.
  • Most pets with hyperthermia have body temperatures greater than 105°F, and a reasonable goal of cooling is to reduce your pet’s body temperature to 102.5-103°F while transporting them to the closest veterinary facility. 
  • Do not attempt to force water into your pet’s mouth, but you may have fresh cool water ready to offer should your pet be alert and show an interest in drinking.
  • Do not leave your pet unattended for any length of time.

Severe hyperthermia is a condition that affects nearly every system in the body.  Simply lowering the body temperature sometimes fails to address the potentially catastrophic events that often accompany this disorder.

A pet suffering from hyperthermia should be seen by a veterinarian as soon as possible.

Dr. Lamb is the Veterinarian at the Manchester Animal Hospital.