Hyperthermia

Much like in humans, heat stroke occurs when the dog's body produces or absorbs more heat than it can dissipate. Dogs do not tolerate heat well, as they can only sweat through their paws and dissipate excess heat by panting. Therefore, heat stroke is an emergency that requires immediate attention and prompt treatment, especially if the dog is exposed to environmental temperatures of 104 degrees Fahrenheit (40 degrees Celsius) or above with no shade or water.

Symptoms and Types

Heat stroke begins with heavy panting and difficulty breathing. The tongue and mucous membranes will begin to appear bright red. Other signs include:

• Vomiting
• Restlessness/Lethargy
• Increased sweating
• Increased grooming activities, in an attempt to cool off
• Stumbling gait
• Collapse
• Coma
• Seizures

During advanced stages of heat stroke, the dog's saliva will become thick and sticky. Also, if its rectal temperature approaches 104 degrees Fahrenheit, the dog's body systems may shut down, and the dog may die.

Sunstroke is similar to heat stroke, but occurs when the dog reaches a high body temperature due to direct sunlight.

Causes

Exposure to a very hot or humid environment, combined with inadequate ventilation, can lead to heat stroke. Other common causes include:

• High level of physical stress
• Excessive exercising
• Increased weight (obesity)
• Respiratory diseases

Diagnosis

If you suspect your dog is suffering from heat stroke, you must cool it down immediately and take it to a veterinarian for medical assistance. The medical definition for heat stroke in dogs refers to a rectal temperature of 103 degrees Fahrenheit or more.

Treatment

Applying cool water to the dog's body or immersing your dog's entire body in water are two quick ways to lower your dog's body temperature (do not use ice water, and keep its head above the water). You can also apply ice packs to its head and body, while giving it cold water with salt to drink is good for rehydration.

Monitor its rectal temperature and continue the cooling process until the rectal temperature falls below 103 degrees Fahrenheit (39 degrees Celsius). At this point, stop the cooling process and dry the dog. Further cooling may induce hypothermia and shock.

In severe cases of heat stroke, your veterinarian may administer saline intravenously to reduce the body temperature and compensate for the fluid loss, especially if the dog is vomiting. Cold-water enemas may also be given.

During its hospitalization, your veterinarian will record your dog's rectal temperature at regular intervals to modify the treatment accordingly.

Living and Management

It is better to seek professional advice when dealing with this condition, as delayed and secondary problems may develop, including kidney failure, spontaneous bleeding, irregular heartbeat, and seizures. These complications can occur hours or days later. In addition, heat stroke can be associated with laryngeal edema. This worsens the breathing problem and may require an emergency tracheostomy. An injection of cortisone before the onset of respiratory distress may prevent this problem.

Prevention

Heat stroke can be prevented by taking caution not to expose a dog to hot and humid conditions. This is especially applicable for dogs with airway diseases and breeds with shortened faces (e.g., the Pug, Bulldog, Shi Tzu).  Also, while traveling in cars, make sure that the dog is well ventilated by placing it in a wired cage or in an open basket, and never leave your dog in a car with the windows closed, even if the car is parked in the shade. Be sure to provide plenty of water, as well as shade, to dogs that are out in the open for a long time.