At a glance
Also called: Hyperthermia
About: Heatstroke is a life-threatening condition caused by the body overheating, usually as a result of prolonged exposure to high temperatures. It has many catastrophic effects on the body.
Symptoms: Panting (open-mouthed breathing), bright red tongue, dark red gums, weakness, rapid pulse, wobbly gait, vomiting, diarrhea, drooling and blood in the urine.
Diagnosis: This based on presenting symptoms and a history of exposure to extreme temperatures — baseline tests, including biochemical profile, complete blood count, and urinalysis to evaluate the organs for damage.
Treatment: Decrease body temperature with cool enemas or intravenously. Oxygen therapy if needed. Cortisone injections and close monitoring.
What is heatstroke?
Medically known as hyperthermia, heatstroke is a life-threatening medical condition in which the body’s internal organs (liver, kidneys, lungs, heart, and brain) begin to shut down as a result of elevated body temperature caused by high temperatures and humidity.
Cats protect themselves against high temperatures by panting and licking their fur; however, they can overheat very quickly. More so than humans, as panting isn’t a particularly efficient way to cool down the animal.
The normal body temperature of a cat is 100 – 102.5°F (37.7 – 39.1°C)., temperatures over 104 (40 C) are with central nervous signs (CNS) are defined as heatstroke. CNS symptoms develop due to the brain overheating.
Heatstroke is a medical emergency which can lead to organ dysfunction, blood clotting disorders, coma, and death.
Prolonged exposure to high environmental temperature (non-exertional heatstroke) or activity in hot weather (exertional heatstroke) where the body is no longer able to cool itself down efficiently. Any cat can develop heatstroke; however, some are at greater risk.
- Brachycephalic breeds with short faces such as Persians, Himalayans, and Exotics
- Old cats
- Very young cats
- Sick cats
- Cats with heart conditions
- Cats with medical conditions which affect breathing
- Pregnant and nursing queens
- Rapid panting
- Bright red tongue
- Dark red gums
- Salivating (drooling)
- Rapid pulse
- Wobbly gait
- Capillary refill time of less than 1 second
- Vomiting (possibly with blood)
- Diarrhea (possibly with blood)
- Bleeding from the nose (this is indicative of disseminated intravascular coagulopathy (DIC), which is a condition in which the blood-clotting system fails
Never leave your cat in a parked car
- Even in the cooler months, but this is especially important in hot weather. If you are travelling with your cat in the car, provide adequate ventilation or use the air conditioning.
- If your cat is allowed outside (either free to roam or in an enclosure) make sure they have access to a shaded area where they can escape from the sun and heat.
If your cat is indoors only, give him access to a cool area
- It is especially important not to confine the cat to any room where temperatures are especially high, such as a sunroom. Rooms with large windows or east-facing rooms (in the Southern Hemisphere) tend to become hotter in afternoons so make sure your cat has access to cooler parts of the house. Cool flooring such as tiles and slate can offer relief. My dogs like to lie on the kitchen floor on hot days as it’s away from the sun and has slate flooring.
Provide drinking water
- Always ensure your cat has an adequate supply of fresh, cool, clean water, indoors and outdoors. On warmer days, add some ice cubes and make sure you have more than one water bowl. Locate bowls out of direct sunlight.
Avoid strenuous activity
- During high temperatures.
Keep the cat indoors during the hottest hours of the day
- Limit exposure to the outdoors in the hotter months. 11.00am and 3.00pm are the hottest times, keep your cat indoors during this period.
Keep the home cool with air conditioning or a fan
- Keep your cat indoors during hot days, and if possible with the air conditioning or a fan turned on.
Close blinds and curtains
- This can help to keep the room cool.
- Popsicles for cats can be a novel way to keep your cat cool when the heat hits. These can be made from lactose-free cat milk (available from your supermarket) or canned cat food. Add milk or wet food to ice cube trays and freeze overnight. Take one or two frozen catsicles out as a cool treat.
Make cold water bottles
- Fill old soft drink bottles with water (don’t fill right to the top as water expands when it is frozen). Take out and wrap a towel around the bottle. Place where your cat sleeps.
Think for your cat
- I have found that even on extremely hot days my cats won’t always move themselves to a cooler part of the house, sometimes you have to do it for them.
Mild heats exhaustion (body temperature of 104°F or 40°)
- Move the to a cool/shady spot, turn on air conditioning or fans if possible to cool the cat down and help with evaporative cooling.
- Spray the cat with cool water.
- Offer plenty of cool, fresh water to drink.
Why not ice packs or frozen vegetables to the head and between the legs? As the body heats, capillaries dilate (vasodilation) which brings warm blood up to the surface of the skin, which allows heat to dissipate from the body. Applying ice rapidly cools the surface of the skin, which causes vasoconstriction and diverts warm blood back to the core of the cat.
Once the body temperature has returned to normal, stop cooling, or you may cause hypothermia in your cat. Monitor your cat’s rectal temperature, every 5 – 10 minutes. Once you have brought your cat’s temperature down, take him to the vet. The cat may appear to be over the incident, but the damage may have been caused to the organs, so it is always recommended your cat is given a check over by a veterinarian.
Moderate to severe heat exhaustion (body temperature is 105F or 40.5C)
Take the cat to the vet immediately. If possible, have somebody else drive, while you attempt to bring down the temperature on the way via the above methods.
When not to treat at home
- If you don’t have access to a thermometer to determine the body temperature
- Vomiting or diarrhea
- Having seizures
- Body temperature over 105 F or 40.5 C
Take your cat to the veterinarian immediately.
The goal of treatment is to bring the cat’s body temperature back to safe levels as well as manage secondary complications which can occur.
- Your veterinarian will carefully bring your cat’s body temperature down to a safe level with lukewarm water and fans.
Volume (fluid) replacement:
- Intravenous crystalloid solution until the veterinarian sees an improvement.
Manage secondary complications:
- Oxygen therapy will be given if your cat is having difficulty breathing.
- Heatstroke can be associated with swelling in the throat, aggravating the problem. Your vet may give the cat a cortisone injection to treat this. 
- Your cat will be carefully monitored for signs of kidney or liver failure or disseminated intravascular coagulation.
Cats who have suffered heatstroke are at increased risk of developing it again. So it is important to take the necessary steps to avoid this.
Carefully monitor your cat’s health for signs of possible long-term damage caused by the heatstroke and speak to your veterinarian if you see anything unusual.
Watch for blood in the urine.
Your veterinarian may prescribe a special diet which will put less strain on the damaged kidneys.
 Cat Owner’s Home Veterinary Handbook by Delbert G. Carlson and James M. Giffin.