August always feels like the hottest month to me here in Durham. Therefore, I dedicate this column to heatstroke, hoping that together we can save lives.

 

Heatstroke is extreme hyperthermia (greater than 106 degrees Fahrenheit) without the presence of systemic causes such as infection or metabolic abnormality. These body temperatures cause thermal injury to many organs, including liver, heart, kidneys, and the gastrointestinal and nervous systems. Body temperatures over 110.5 F for even a few minutes result in certain death. Heatstroke is common in dogs, but cats left in inappropriate environments can also succumb.

 

As you can imagine, the body works hard to control its temperature! A normal dog's core temperature is maintained within a couple of degrees of 101.5 F by the thermoregulatory center of the brain. There are mechanisms and behaviors for keeping warm, such as shivering and curling into a ball, as well as for cooling down, like panting, vasodilation of skin blood vessels, and seeking cool surfaces and shade. As in humans, dogs cool by evaporation and radiation. However, sweating is limited to the paw pads and has little effect. As for us, ambient temperatures approaching body temperature and increased humidity make it more difficult to cool the body.

Heatstroke can kill your pet. Hopefully we have raised awareness of the danger. Now let's avoid the risks, recognize the signs, and seek appropriate treatment.

The risk of heatstroke rises with hot, humid weather like we "enjoy" here in the summer. Individual risk varies: body fat and heavy coats insulate and hold in heat. Stocky dogs radiate proportionately less heat; muscular dogs produce more. Brachycephalic, or short-nosed, dogs have upper airway abnormalities (that boxer snore!) preventing proper breathing and dissipation of heat. Older pets, excitable animals and those with metabolic or cardiovascular disease may be less able to regulate temperature.

No dog should be left outside without plentiful fresh water, protection from other animals, shade and shelter. Never leave your dog out unless they have been gradually accustomed to the season, whether summer or winter. Even acclimated, well-sheltered dogs should not be out over 95 F with high humidity.

Of course, NEVER leave your pet in an enclosed space like a car or carrier where they cannot escape temperatures that rise unbelievably fast and high (this also applies to indoor situations, such as heated drying cages). Dogs should be exercised only as tolerated, preferably in the early morning.

Animals in heatstroke are often panting, lying on their side, and salivating. However, they may also be comatose, agitated or seizuring. You may see vomit or diarrhea and abnormal gum color. These signs may progress to death. Rapid action saves lives; delays result in poorer outcomes. Studies have shown an overall mortality rate of 50 percent.

Treatment begins with proper cooling. If you suspect heatstroke, move immediately to a cool place and contact a vet. As many local hospitals have limited facilities, call first to make sure treatment is available. If you will be traveling more than a few minutes, you may be advised to wet your pet with cool (NOT cold, as this will slow internal cooling) water. Animals will need 24-hour care, so be prepared to transport to an emergency or referral center.

Once examined and hospitalized, your vet will treat your pet. This may include further appropriate cooling, subsequent warming, intravenous support, antibiotics and other medications to protect and support the function of essential body systems. Treatment is expensive: This is a case of prevention being the best medicine.

Have a safe August and September, and thank you for caring for your pets!

Maia Tcheng Broussard's columns appear on the first Sunday of the month. She has worked in the veterinary field in Durham since 1994. Dr. Broussard is a general practitioner at Westside Animal Hospital, a certified canine rehabilitation practitioner, and has a special interest in behavior medicine. Contact her at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .