Heat stroke is a common veterinary emergency caused by abnormally high elevations in core body temperature. It primarily occurs in dogs in poorly ventilated hot humid environments, such as pets left in cars during the summer months, but it can also happen to a dog with a thick coat taking it’s first long walk of the season on a warm spring day. In late spring and the first weeks of summer pets have not had time to acclimate to the heat. Exacerbating factors include environmental humidity, water deprivation, obesity, and exercise that the animal is not typically used to doing. In addition, brachycephalic (short-nosed) breeds like pugs and bulldogs, and dogs with upper airway diseases like laryngeal paralysis are also more likely to develop problems.
Clinical signs seen with heat stroke include excessive panting, dark brick red gums, diarrhea, vomiting, wobbly gait, hypersalivation, and collapse. In severe cases, loss of consciousness or altered mental status, muscle tremors, listlessness and seizures have been seen. High rectal temperatures of 104.9 to 109.4 degrees can lead to severe problems (normal temperatures for dogs and cats range from 100 to 102.5) in multiple body systems and can cause organ failure.
If a pet is identified to be suffering from heat stroke, quick action should be taken. Spray the pet with cool, not cold, water if readily available and take your pet to their veterinarian or local veterinary emergency clinic immediately. During transportation, keep car windows open or the air conditioning on to continue to cool the pet. Alternatively, fans can be used. Dropping the body temperature as soon as possible provides the best outcome and reduces damage to internal organs. However, caution must be used as making the pet too cold can also cause problems.
Prognosis is guarded depending on the severity and presence or absence of complicating factors. Heat stroke can cause shock and affect major organ systems in the body, including the brain and neurologic system, gastro-intestinal tract (leading to ulcers, bloody diarrhea and vomiting), kidney failure and bleeding problems. It is recommended to seek veterinary care as soon as possible for further evaluation and emergency treatment.