Here in Southern Ontario the routine starts to be familiar, summer arrives, the weather warms, sooner or later the first “Heat Alert” is issued. Everybody seeks out air conditioning, arms themselves with water, avoids the sun, slows down and waits for it to pass. We rarely have to wait long before the news reports the first pet (or child!) to die trapped in a car. Many of us shake our heads and mutter “when will people learn?” But here is a more important message – your pet does not need a car to succumb to heat stroke! Veterinarians can anticipate ending most “Heat Alert” days trying to save the life of at least one pet succumbing to heat stroke. Relatively FEW of these patients will have been confined in cars.
Heat Stroke occurs when heat generated within the body exceeds the body’s ability to dissipate heat. Most people assess their pet’s ability to manage the hot weather by comparing their young, fit dog to themselves – if you are doing OK in the heat, so should your pet, right? WRONG!!! Your pet will start to generate heat the same as you, but their ability to dissipate heat is MUCH worse than you! This causes their internal body temperature to rise much faster than your own.
Why can’t they dissipate heat very well? For one – they wear a fur coat constantly! Our pets are unable to sweat (other than a small amount through the pads on their feet). Sweating captures heat from the body in the perspiration droplets, which are then evaporated from the skin, dissipating heat and helping to prevent over-heating. The more of your skin surface that sweats, the faster you cool. Pets can pant though, right? Sure – and panting helps to cool the body the same way sweating does. But let’s take a moment to consider the surface area of your dog’s tongue compared to the surface area of all your sweating skin. Now we start to understand how Rex’s core body temperature can start to skyrocket while you are still sipping your ice water and fanning yourself sitting next to him.
Now we can consider a few more factors that can worsen Rex’s over heating 10-fold. If any ONE of the following factors also apply to Rex, he may be in grave danger during a heat wave: Is Rex overweight? Is Rex a “short-nosed” (brachycephalic) breed? (these include breeds or mixes of pugs, Boxers, Bulldogs, Shih Tzus, Lhasa Apso – and many more). Is Rex being exercised? (walks, running or playing with other dogs). Does Rex always have access to water and shade? Is Rex older? Does Rex have even minor respiratory or heart disease?
Please take a moment to consider what actually is occurring in the body as Heat Stroke sets in. It is not “just getting too hot”. Your pet’s normal core body temperature is 38C-39.2C. As the ambient air temperature and humidity start to rise your pet begins to pant and drool in an effort to dissipate heat. The body then vasodilates; blood vessels expand trying to bring more blood to the skin surface to allow heat to dissipate via radiation & convection. Unfortunately this vasodilation also results in a drop in blood pressure. As blood pressure drops the body can no longer sustain heat dissipation through radiation & convection, and core body temperature starts to rise dramatically. Tissue damage inside the body starts to occur as the core body temperature rises over 41.5C (only 2 C above normal!). The tissue damage quickly results in gastrointestinal injury, kidney failure, brain swelling, coma, brain damage, liver and heart failure and then death. A core body temperature over 43.5C (only 4C above normal) for just a few minutes, can cause death.
What are the symptoms of heat stroke? The 1st signs are panting, drooling and an increased heart rate. We are very accustomed to our dogs panting and drooling, we rarely take notice of it. But if the weather is hot or humid – when your dog starts to pant and drool you should be taking active measures to get them cooled down. You may be observant enough to notice your pet’s gum colour is darker red than usual, but this will then change to pale, grey gums as their blood pressure drops. Next symptom – collapse! Wow – see how quickly that can sneak up on you? After collapse things get critical fast, you may see vomiting, diarrhea, bloody vomit, or bloody diarrhea, then they slip into unconsciousness.
What to do if you suspect heat stroke: When your dog starts to pant and drool, get them into air conditioning right away (even your car with the air conditioning running high!). If there is no air conditioning get them into the shade, make them calm down. Excited dogs may still want to play at this point, they might play right up until they collapse. You know better, force them to settle down. Offer water to drink. Apply a cool wet towel to their belly, or wet down their fur. If the panting and drooling subsides in a few minutes then retire to the air conditioning and avoid the outside. If the panting and drooling persist, or your pet is reluctant to stand up then you need to get them to a veterinarian right away. Do not dunk a collapsed pet in cold water as it may worsen their shock.
How to prevent Heat Stroke: Ensure your pet ALWAYS has access to water and shade; please keep your pets indoors ,in the air conditioning, during a Heat Wave; please NEVER take your pet out in the car during the hot weather – they would rather miss you during your errands than possibly die; never exercise your dog during the day in a Heat Wave; if your pet is a “short-nosed” breed, older, overweight or has breathing or heart concerns do not exercise them AT ALL during a heat wave and be very cautious during any warm weather.
I cannot stress enough how serious and how common Heat Stroke is. It occurs quickly and with little warning. It happens to the most loving and responsible pet owners – just like you! Be aware, be proactive! Any pet even suspected of having heat stroke to needs to be seen by a veterinarian immediately, they require aggressive intravenous fluid therapy, oxygen support, cooling, blood work and medications. If you are not near your veterinarian or they are not open, your pet can always receive potentially life-saving treatment, 24 hours a day, at the ***Niagara Veterinary Emergency Clinic; 3300 Merritville Hwy (near Brock University) 905 641-3185***.
