Early recognition of the symptoms of heat stroke is key to a prompt recovery. If your dog's increased body temperature can be linked to environmental temperature, such as weather, an enclosed room, grooming cage or exercise, the first immediate step will be to attempt to lower the body temperature.
Some external cooling techniques include spraying the dog down with cool water, or immersing the dog's entire body in cool – not cold – water; wrapping the dog in cool, wet towels; convection cooling with fans; and/or evaporative cooling (such as isopropyl alcohol on foot pads, groin, and under the forelegs). Stop cooling procedures when temperature reaches 103° F (using a rectal thermometer) to avoid dropping below normal body temperature.
It is very important to avoid ice or very cold water, as this may cause blood vessels near the surface of the body to constrict and may decrease heat dissipation. A shivering response also is undesirable, as it creates internal heat. Lowering the temperature too quickly can lead to other health problems, a gradual lowering is best. The same guideline applies to drinking water. Allow your dog to drink cool, not cold, water freely. However, do not force your dog to drink.
You will need to have your dog examined by a veterinarian to ensure that a normal temperature has been reach and has stabilized, and that no long lasting damage has taken place within the organs or brain. Complications, such as a blood-clotting disorder, kidney failure, or fluid build-up in the brain will need to be immediately and thoroughly treated. Your doctor will check your dog's blood clotting times, and kidney function will be analyzed in part by urinalysis. An electrocardiogram may also be used to observe your dog's heart capabilities and any irregularities that might have resulted as a result of the hyperthermic condition.
In many cases patients need to be hospitalized until their temperature is stabilized, and may even need intensive care for several days if organ failure has occurred. Oxygen supplementation via mask, cage, or nasal catheter may be used for severe breathing problems, or a surgical opening into the windpipe or trachea may be required if upper airway obstruction is an underlying cause or a contributing factor. Intravenous feeding or a special diet may need to be prescribed until your dog's organs have recovered to handle a normal diet again.
Underlying disease conditions or factors that increase the likelihood of developing hyperthermia will also need to be corrected and treated if possible (e.g., obesity, heart/lung disease, grooming with respect to environmental temperatures, restricting activity with respect to age).
Dogs that have suffered an episode of hyperthermia are prone to experiencing it again. Be aware of the clinical signs of heat stroke so you may respond quickly to an episode. Know how to cool your dog properly, and talk to your veterinarian about the appropriate procedures for maintaining proper body temperature and lowering it in the safest way possible.
If your dog is older, or is a brachycephalic breed that is prone to overheating, avoid taking your dog out during the hottest times of day, or leaving the dog in places that can become too hot for your dog, like a garage, sunny room, sunny yard, or car. Never leave your dog in a parked car, even for only a few minutes, as a closed car becomes dangerously hot very rapidly. Always have water accessible to your dog; on hot days you might even add ice blocks for your dog to lick.
If you have not done so already, you may wish to invest in a pet CPR class. It can mean the difference between your dog living or dying should an episode of heat stroke occur.