Heat Related Illness

Heat Related Illness

By Dr. Ed Mapes
Stonebridge Animal Hospital
McKinney, Tx 75071

High environmental temperatures, especially with elevated humidity, pose a serious risk of heat injury to our pets. Those especially vulnerable are animals with heart conditions, obesity, large and very muscular breeds, brachycephalics, and older pets. We see very few cats with heat injuries, but they are certainly susceptible as well. Those trapped in enclosed areas without fresh air can succumb rapidly.

Heat injury occurs when body temperatures rise in excess of 105F degrees. Elevated body temperatures and rapid fluid loss causes hypovolemic shock and damage to all organs and tissues in the body. There are ascending stages of severity in cases of heat injury, just as is seen in humans.

Early cases involve elevated temperature only. Remember that animals can’t dissipate heat with perspiration; their only means of cooling themselves are to pant and radiate heat from the ear flaps. These animals pant heavily and seek to escape from the heat. Removing these pets from the heat and supplying cool water usually suffices in these cases.

More advanced hyperthermia begins when panting fails to control body temperature, leading to dehydration and the cascade of tissue damage. Symptoms include red mucous membranes, vomiting, severe dehydration, loss of mental acuity, weakness leading to collapse, rapid heart rate, seizure, and loss of consciousness. Pets with these symptoms are in a true emergency situation and must receive treatment to bring down body temperature immediately.

Treatment is aimed at reducing body temperature and checking for secondary problems. Immersion of the animal in a slurry of ice and water or covering the body with towels soaked in the icy water is essential. In the hospital we begin several intravenous lines to deliver fluids, replace electrolytes, and administer medications to counteract shock. We also monitor the EKG to detect heart rhythm disturbances and take blood to check for organic failure and monitor the acid/base status and blood clotting.


This ice and water slurry cools immersed towels, which are used to wrap the patient for cooling.

Since the kidneys are at high risk, we insert a urinary catheter to monitor urine output. IV fluids must be stopped if the kidneys are damaged and cannot produce urine. In that case we administer diuretics to initiate urine formation and observe closely.
The temperature should be monitored continuously as treatment proceeds. We also assess heart and kidney function, level of consciousness and hydration status. When the temperature falls to less than 103 degrees F, patients usually respond and feel much better.
After the initial emergency treatment, these patients should be kept in a well-ventilated, cool room and prevented from vigorous activity for the next day. Those with organ damage must receive appropriate medications and monitored closely with follow-up testing. Susceptible animals must be watched closely whenever exposed to elevated temperatures because recurrence would be very likely.

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