The Dog Days of Summer

Preventing Heat Stroke

By Elisa M. Mazzaferro
MS, DVM, PhD, Diplomate ACVECC
Director of Emergency Services,
Wheat Ridge Veterinary Specialists
www.wheatridgeanimal.com

When the weather warms up, a lot of people head outdoors with their pets to enjoy the change of seasons. Heat-induced illness, or heat stroke, is unfortunately a common occurrence during the spring and summer months. Heat stroke occurs when heat gain exceeds the body's ability to dissipate heat. Common causes of heat stroke are exposure to high temperatures and humidity, and exertion or exercise.

While it may seem intuitively obvious that keeping a dog in a locked car can result in serious damage or death, it is not always obvious that heat stroke can still occur with the car windows open, or with the windows closed and the heater blowing on a very cold day. Dogs can also develop exertional heat stroke while exercising if they are not allowed to rest or they do not have access to cool water and shade. Even the most acclimatized athletic dog needs rest every 30 to 60 minutes on a very hot day, particularly after they have spent the majority of the winter indoors. Breeds like Pugs, Pekingese, Boston Terriers, and Bulldogs are predisposed to heat-induced illness due to inherent airway abnormalities that increase the work of breathing. Do not allow these types of dog to be excessively active during the warmest part of the day. Other predisposing factors include obesity, previous history of having heat stroke, and an inability of the upper airway to open sufficiently during breathing. This latter condition is known as "laryngeal paralysis" and can be observed in any breed of dog, but is most common in older Labrador Retrievers.

Signs of heat stroke include excessive panting, often with excessive noise. Other signs include difficulty walking, excessive salivation, diarrhea, vomiting, and collapse. In its most severe form, heat stroke can be manifested as muscle tremors, altered level of consciousness, dilated pupils, vocalizing, bloody urine and nosebleed, seizures, and coma. Severe heat-stroke can result in widespread damage to tissues throughout the body. Without early and rapid recognition and treatment, heat stroke can be quickly fatal.

If you think that your dog is developing signs of heat stroke, stop activity immediately and move them to a cool, shady area or indoors with access to cool water. Put a towel soaked in ROOM TEMPERATURE water on the dog, and put him or her in front of a fan to expedite cooling. It is very important not to shock the system by soaking the animal in cold water or ice, as this can lead to overcooling and shivering, both of which have been shown to be associated with a less favorable outcome.

Next, bring your dog to the nearest veterinary facility for diagnosis and treatment. Diagnostic tests and treatment may include bloodwork, intravenous fluids, antibiotics, plasma transfusions, and hospitalization for monitoring.

With aggressive treatment, many animals can survive heat stroke; however, the best treatment is prevention itself. Slowly acclimatize your dog to exercise during the early spring, and never exercise him for more than 30 minutes without taking a rest. Provide plenty of cool water and shade at all times. If your dog is overweight, or has respiratory problems, walk him during the coolest times of the day, then keep him indoors in air conditioning, whenever possible. With these guidelines, both you and your furry companion can enjoy the beautiful outdoors, without needing a trip to the hospital.