Author: Dr. Clarissa G. Noureddine, DVM, MS, MS
What is Heatstroke?
Heatstroke is an acute, progressive, life-threatening emergency where the body temperature increases to a point that causes thermal (heat) injury to organs.
What Causes Heatstroke?
- High environmental temperature (Classic Heatstroke)
- Strenuous Exercise (Exertional Heatstroke)
Who is at Risk for Heatstroke?
- Older animals
- Animals with dark/ thick hair coat
- Dogs with laryngeal paralysis
- Animals with brachycephalic obstructive airway syndrome
- Overweight / obese pets
- Animals with Cardiovascular or Lung Disease
- Any animal that has not been acclimated to warmer temperatures
- Animals experiencing overexertion, especially on warm or hot days
What Are the Symptoms of Heatstroke?
- Increased heart rate
- Elevated body temperature
What Are the Secondary Complications of Heatstroke?
- Organ injury or failure can result from the heat injury, decreased blood perfusion, and thromboembolic disease.
- Kidney or liver failure are possible
- Lung injury and heart arrhythmias can occur
- Gastrointestinal signs (including vomiting, diarrhea, bloody stools)
- Changes in clotting abilities
Can Heatstroke Be Treated?
Treatment should be attempted as soon as it is recognized the animal is having trouble regulating body temperature. While the animal should be taken to a veterinary clinic immediately, owners can (and should!) begin cooling animals right away. Studies have shown that dogs cooled by owners even before hospital arrival had a lower mortality rate than those who were not cooled. Cooling methods can include offering water to drink (if conscious), spraying the animal with lukewarm water, placing a cold / wet towel over the animal, and putting the animal in front of a fan. Once the patient arrives at the clinic, the goals of treatment include cooling the body, replacing fluid volume to help increase perfusion, and addressing any secondary complications that arise. Unfortunately, the prognosis for heatstroke is guarded, and mortality rates can reach 50%.
What Can Be Done to Prevent Heatstroke?
- Recognize that heatstroke is a risk for any animal that is unable to regulate it’s body temperature.
- Never leave animals in cars on warm or hot days – not even for a minute!
- At times when the heat and/or humidity are increasing and animals are still in an acclimation period, do not permit the animal to run or play outdoors. Acclimation is partially complete within 10 to 20 days, but it can take up to 2 months for animals to fully acclimate to warmer temperatures.
- If an animal seems to be developing heatstroke, cool the animal and take him or her to a veterinarian.
- Keep your pet inside in the air conditioning on hot days – especially if you have a pet that is at increased risk for heat stroke due to a physical or medical condition.
- Always provide access to fresh, cool water.
- Outdoor pets should have access to shade, and outdoor activities should be limited on hot days.
- Walks can be taken during the cooler parts of the day.
- Bruchim Y, Klement E, Saragusty J, Finkeilstein E, Kass P, Aroch I. Heat stroke in dogs: a retrospective study of 54 cases (1999-2004) and analysis of risk factors for death. JVIM 2006; 20(1):38-46.
- Holowaychuk, M. Heatstroke in Dogs. Clinician’s Brief. June 2016.
- Johnson SI, McMichael M, White G. Heatstroke in small animal medicine: a clinical practice review. JVECC. 2006;16(2):112-119.