Hyperthermia (Heatstroke/Heat Exhaustion)

Heatstroke is a serious and often life-threatening condition dogs are susceptible to whenever the weather becomes hot and humid. Dogs cannot sweat; therefore, they do not efficiently handle heat stress. They exchange heat mostly through panting. Heatstroke is most common in large breed dogs, overweight dogs and dogs with short noses.

The most common clinical signs of heatstroke are weakness, loss of balance, excessive panting, increased salivation, loud or roaring breath sounds, mental dullness, collapse and death. Body temperatures over 106 degrees Fahrenheit are a critical emergency and require immediate treatment. As body temperatures go above 107 degrees Fahrenheit, organ damage occurs, shock and cardiovascular collapse ensues, brain swelling and disseminated intravascular coagulation (DIC) are common complications that result from heatstroke. If the body temperature goes above 109 degrees Fahrenheit, the prognosis becomes very poor.

Death from heatstroke can occur fairly quickly. It can be as short as 20 minutes, as in a “closed car” situation. It is more common for dogs to experience heatstroke in the first few days of warm weather when they are becoming acclimated to the heat and for it to occur in conjunction with exercise or excitement. Heatstroke may occur within an hour or more under these circumstances, but could develop more quickly if the pet was already struggling with the heat prior to exercise.

TIME IS OF THE ESSENCE WHEN DEALING WITH HEATSTROKE. Immediate treatment is critical to success when dealing with hyperthermia. Delays can be harmful or even fatal.

• Come to the hospital immediately when a dog collapses. The amount of time from collapse to admission results in more cases of disseminated intravascular coagulation.
  
  
• Cool your dog off only if it will not delay arrival at a veterinary hospital. When cooling the pet, use cool water (not cold water) bathes or rinses. This should be done immediately for only a few minutes, and then the pet should be taken to the veterinary hospital or veterinary emergency clinic immediately.
  
  
• Take extra precautions with overweight dogs on hot, humid days. Overweight dogs have a case-fatality rate double that of normal weight dogs.
  
  
• If you have a bulldog, pug, shar-pei, Pekinese or other brachycephalic breed, limit their outdoor access on hot, humid days. The short nose of these dogs may not allow adequate cooling on the hottest summer days. These breeds are twice as likely to develop heatstroke compared to other dogs.
  
  
• Large breed dogs, such as golden or Labrador retrievers, rottweilers, English bulldogs and mastiffs are twice as likely to develop heatstroke as other dogs. They should be exercised only when the heat and humidity are low. Heatstroke occurs more frequently when the discomfort index is higher than average for a given day. Discomfort index is a measure of heat and humidity.