Thanks to Dr. Timothy Hodge for this guest post.
Heat stroke is a potentially deadly disorder for dogs and humans. It’s defined as “a state of extreme hyperthermia with temperatures above 106 F, that results in thermal injury to the tissues.” Heat stroke occurs when heat generation exceeds the body’s ability to dissipate or remove heat.
This condition is rare in cats, but occurs frequently in dogs, especially those with short muzzles like pugs, bulldogs, and pekinese; obese dogs; those with breathing disorders; those enclosed in cars, and those that are exercised in hot, humid weather.
While rare, heat stroke can occur in those pets that are confined to non-ventilated areas, deprived of water and/or shade, or subjected to forced heat such as hot dryers with grooming.
What are signs of heat stroke in dogs?
Early signs of heat stroke are panting and rapid breathing, increased heart rate, with bounding pulses.
Early signs of heat stroke in dogs include:
- Panting and rapid breathing
- Increased heart rate, with bounding pulses
Later signs of heat stroke in dogs are:
- Vomiting and diarrhea
- Sticky gums
- Tented skin (when lifted)
- Seeming dazed, disoriented, and depressed
- Excessive drooling and increased salivation
The salivation occurs as the body works harder and harder to get rid of the pent up heat. As heat stroke progresses, severe breathing distress occurs. Many dogs will seem as if they can’t catch their breath. Flip the lips and look at the gums and tongue. The gums become bright red. Bruises can be seen on the gums or skin.
As the condition worsens, collapse, seizures, depression, and abnormal mental states occur. Increased urination, bloody diarrhea, and vomiting of blood may occur due to damage of the blood vessels in the intestines and stomach.
A sign that the condition is worsening is that the previously dark and reddish gums become pale and ashen. The pulses then weaken. The elevated body temperature may decrease to below normal and neurological signs such as seizures and coma can occur and often precede death.
Why do heat strokes occur?
Temperature regulation is controlled by a special center in the brain. Core body temperature is kept relatively constant in the normal dog under the usual surrounding temperature fluctuations by this area of the brain.
When the temperature surrounding the dog and thus that of the dog increases, the regulatory center in the brain stimulates panting, drooling, and dilation of the bodies blood vessels to cool the body by evaporation and radiation.
Since dogs sweat mainly from their footpads, sweating is not an effective means of cooling for dogs. When the dog’s ability to keep pace with natural cooling mechanisms fail, heat stokes occur.
What is the prognosis for dogs with heat stroke?
Overall prognosis for patients with heat stroke depends on the length of time the animal had an elevated temperature, the degree of temperature elevation, the amount of organ damage incurred, and the response to intensive supportive care.
Recovered animals may remain with some neurological deficits. In one study of 54 cases, the overall death rate was 50%.
What is the treatment for dogs with heat stroke?
Reduction of core body temperature is essential. Owners should start cooling efforts prior to and on the way to the veterinary hospital or veterinary emergency facility.
The dog should be immersed in cool water, using a tub or garden hose. DO NOT USE ICE WATER as this causes the blood vessels to constrict and traps heat. Shivering may also occur and generate more heat and worsen the hyperthermia and heat stroke. A fan can be used to increase cooling by evaporation.
Spraying the footpads with alcohol can improve evaporation and dissipation of heat. A rectal thermometer should be used to monitor the temperature every few minutes. Once the pet reaches the veterinary hospital, the health care team will take over with more intense therapies as needed.
How do we prevent heat stroke in dogs?
- Do not cage animals outdoors without adequate shade or water.
- At very high temperatures, keep pets indoors. If there is a heat advisory for people, then the same is true for pets.
- Do not leave animals in closed compartments exposed to the oven effects of the sun, such as in a car. Even with the windows cracked, the temperature can rise to very high levels, quickly.
- Do not exercise dogs in the heat of the day. Very early morning or late evening is the best time to walk or exercise your dog, when the temperature outside is cooler.
- Monitor dogs when they are laying in the sun, especially old or infirm dogs as they are more prone to heat stroke at these times.
Take the heat off your pet with proper preventive measures. The dog days of summer can be an enjoyable time for all.
Dr. Timothy Hodge is a Tampa, FL veterinarian and has been practicing small animal and exotic medicine since 1995. Dr. Hodge enjoys all aspects of veterinary medicine with special interests in Internal Medicine, Acupuncture & Herbal Medicine, Surgery, Dermatology and being a partner in the human-animal bond.
Top image via Flickr/Darcy Knoll