Heatstroke & Hyperthermia in Our Pets

Summer is finally here, and as the temperatures begin to rise, it is important that we keep all of our pets cool and comfortable. As people, we can change our clothes, turn on the air conditioning, or have a cool shower to cool ourselves down. Our pets are often limited to how they can dissipate heat from their bodies. Dogs will often pant to cool themselves down, while cats may lick their fur or sweat through the pads of their feet. Each of these behaviours to help regulate their core body temperature. However, when the temperature rises significantly, or our pets are incapable of escaping the heat from their environment. These coping mechanisms are often overwhelmed, and clinical hyperthermia can ensue.
Hyperthermia in dogs and cats is typically consistent with a body temperature higher than 103°F (39°C), while clinical heatstroke may be noted when temperatures rise above 106°F/41°C.

Overheating of the body leads to thermal damage of the cells, which, if left untreated, can lead to multisystemic organ dysfunction. Heatstroke is more commonly seen in dogs than cats but can occur in any species. Overweight animals, with pre-existing medical conditions (ex. Brachycephalic breeds or animals with congestive heart failure), are predisposed to developing heatstroke.

Heatstroke may be triggered by:

  • Being locked in a car without adequate ventilation.
  • Excessively hot environmental temperature.
  • Inability to access shade.
  • Over-exertion and excessive exercise.
  • Restricted access to water.

It is important to keep a close eye on your pet, to allow you to catch any signs of heatstroke: Panting, excessive drooling, high heart rate, dullness, muscle tremors, weakness.

Once you have acknowledged possible heatstroke in your pet, the first thing you need to do is to remove them from the source of excessive heat and find a safe way to cool them down. Spray or immerse them in water by soaking towels in cold water and rolling them under armpits and groin help to cool the major external blood vessels. Convection cooling with fans is also useful to help bring down their temperature. Avoid using ice, as it tends to constrict the peripheral veins and prevents the circulation of blood to the extremities. Give access to fresh, cool water, and keep in a cool shaded area while you transport them to your nearest veterinary clinic.

Patients should be closely monitored during the cooling down period, and for the following 24hrs as one episode of hyperthermia predisposes an animal to future episodes. If you have a rectal thermometer at home, use it to take regular temperatures, and to make sure you avoid causing hypothermia by excessive cooling.

In any case, prevention is better than cure. Make sure never to leave your pet in a hot car, tied outside, or left in direct sunlight unattended without adequate ventilation. It is the best way to stop heatstroke from occurring. Always have fresh water available, and clipping long-haired breeds will make sure that all our pets can remain cool to enjoy the summer.

Written by: Dr. Aoife Hand, DVM