Heat stroke in dogs: Having a hot dog is not cool

Last summer I walked out of Jewel, and as I put my groceries in my car I happened to glance at the car next to mine.  The windows were opened about three inches all around, and inside the car was a Boston terrier.  He was panting so hard that I could clearly hear his distress.  I stood there for a few minutes, then decided I was either going to break the car window, have a Jewel employee try to page the owner, or call the police.  Fortunately the owner returned to her car with a cart full of groceries (clearly at least a 20-minute shopping trip).  Although my blood was boiling, I told her as politely as possible that I was a veterinarian and that she was putting her dog’s life at risk due to heat stroke.  “Mind your own business” was her retort.

While some people think it’s okay to leave a dog in a hot car – it wasn’t the first time I’d seen that happen – I think most pet owners know better. But what they might not realize is that other scenarios can cause heat stroke just as surely as a sizzling sedan. Those include:

• Exercising strenuously in hot, humid weather.
• Being muzzled while put under a hair dryer, or getting overheated in a dryer cage.
• Being confined on hot concrete or asphalt surfaces.
• Being confined without shade and fresh water in hot weather.

Although it’s true that too much exercise in hot weather can be dangerous, I’ve found that most cases of hyperthermia involve confinement. The pet’s anxiety at not being able to escape the heat exacerbates the rise in body temperature.  A rapidly panting, over-exerted dog who is brought indoors to air-conditioning and given water will usually be fine.  If the same dog is tied up without shade on a hot day, even with a big bowl of water, it’s a recipe for heat stroke. 

There are risk factors that predispose certain dogs to hyperthermia.  A few weeks ago I saw Charlie, a 13-year-old Lab mix who had been running at the dog park and collapsed.  He was taken to the emergency clinic with a temperature of 104 degrees.  A dog’s normal body temperature is 100 to 102 degrees; the average heat stroke patient presents with a temperature of 105.8 degrees.  Although Charlie had all the symptoms, his body temperature was not typical of a heat stroke patient.  When I saw him a few days later, his breathing was noisy and somewhat labored.  I diagnosed him with a condition called laryngeal paralysis, which makes it hard for him to take in air.  It’s largely a problem in older dogs, especially Labradors and Lab mixes, and predisposes them to overheating.  

Dogs rely on an increase in air flow over the internal nasal folds (called turbinates) to facilitate evaporation and thus cool them off.  Charlie’s inability to move enough air through his nasal passages put him in danger of death from heat stroke.  Except for their paws, dogs can’t sweat, so panting is their way to prevent their bodies from overheating.  Eventually their cooling system will fail if they can’t pant fast enough to dissipate heat.  

Other risk factors for heat stroke include:

·         Age extremes (very young, very old).

·         Heat intolerance due to poor acclimatization to the environment (such       as moving from a cold geographical location to a hot one).

·         Obesity.

·         Poor heart or lung conditioning.

·         Underlying heart or lung disease, such as cardiomyopathy or asthma.

·         Short-nosed, flat-faced (brachycephalic) characteristics common to           such breeds as bulldogs, Shih Tzus, pugs, and Pekingese.

·         Thick hair coat.

·         Dehydration, insufficient water intake, restricted access to water.

The most obvious symptoms of heat stroke are heavy panting, labored breathing, and collapse.  The saliva may be very thick, and the dog’s tongue and mucous membranes may appear bright red, although as shock sets in, they may turn gray or white.  Vomiting, bloody diarrhea, and seizures may occur.  The mortality rate, even with treatment, is 50%.

Most pets with heat stroke should be seen by a veterinarian, but it’s a good idea to treat a pet as soon as possible at home if you recognize the symptoms.  If his rectal temperature is above 104 degrees, begin cooling the dog with a hose, or immerse him in a tub of cool water (not ice water).  Dogs also cool down nicely if they are wetted down thoroughly and placed in front of an electric fan.  Monitor the dog’s rectal temperature every few minutes until it falls to 103.  At that point, stop the cooling process, dry the dog, and give us a call.  If you cool him off further, he may become hypothermic and go into shock.  

If your dog has one or more of the risk factors mentioned above, be especially vigilant, and make sure his or her underlying condition is treated, if applicable.  As for Charlie, my patient with laryngeal paralysis, even mild overheating could result in his death.  I recommended surgery to help open up his airways and stressed that he should be kept indoors in air-conditioning on hot days.  Because of his age, his owners opted out of the surgery, but they’ve now seen firsthand how scary it is to see a dog gasping for air when he’s overheated and will assuredly be diligent about keeping the old guy cool.  

Preventing heat stroke involves common sense:

·         Keep your dog indoors during the hottest part of the day.

·         Never leave your dog in a hot car, not even for a minute.

·         During hot weather, keep exercise sessions very short; during a               serious heat wave, omit exercise altogether.

·         Keep your pet unconfined during hot weather; that applies even if             he’s indoors if you don’t have air-conditioning.

If you see an animal left in a parked car on a hot day, notify someone in the store where the owner was likely to go as soon as possible.  If you can’t locate the pet owner, call the police.  Resist the temptation to smack or verbally assault the pet owner — we now have concealed-carry laws in Illinois, so you never know who’s packing!  A mild admonishment like the one I gave is acceptable; just don’t expect the pet’s owner to appreciate it.

If your dog has one or more of the risk factors mentioned above, be especially vigilant, and make sure his or her underlying condition is treated, if applicable.  As for Charlie, my patient with laryngeal paralysis, even mild overheating could result in his death.  I recommended surgery to help open up his airways and stressed that he should be kept indoors in air-conditioning on hot days.  Because of his age, his owners opted out of the surgery, but they’ve now seen firsthand how scary it is to see a dog gasping for air when he’s overheated and will assuredly be diligent about keeping the old guy cool.