It’s summertime! While you may be spending the next few months lounging at the beach or traveling to exotic, far-off locales, it’s more likely that you’re spending this summer working in a veterinary hospital.
Maybe you’re on clinical rotations at the vet school, or maybe you’re spending the summer at an off-campus job or externship… either way, there’s a good chance that you will see some heat-related emergencies in the next couple of months.
Two of the most common summertime emergencies are directly correlated with rising temperatures: thermal burns, in which the skin is exposed to extreme temperatures, and heatstroke, in which the whole body struggles to cope with elevated temperatures.
Thermal Burns
A dog with thermal burns often presents with a worried owner, who says something like this: “It was such a warm, sunny day that I decided to take Fluffy out for a walk. After we walked for a while, she started to limp and it gradually worsened over the next few minutes. I finally checked her paws and realized that they were red and look burned!!”
On a warm day, concrete or asphalt heated by direct sun can reach temperatures up to 60°F warmer than the surrounding air!(1) This can easily lead to significant paw pad burns, even on a day that doesn’t feel extremely hot. Paw pad burns often take owners by surprise, because many do not realize how warm the pavement can become on a summer day.
Treatment of these burns depends largely upon the severity of the burns. Superficial burns often resolve relatively quickly, because the remaining deep layers of epidermal tissue are capable of regenerating the superficial, keratinized layers. Mild superficial burns may resolve by simply keeping the dog off abrasive surfaces for a few days, while others may require a light protective bandage for up to one week.(2)
In deep burns, however, all layers of the epidermis are lost. The keratinized epithelium must regenerate from intact pad tissues at the edge of the wound and this process takes time. In order to prevent infection and promote epithelial migration, deep burns should be bandaged with a dressing of silver sulfadiazine or Neosporin® cream. A non-adherent primary layer and thick secondary layer should be incorporated into the bandage, to protect the wound until it is fully healed. A Mason metasplint may also be used to help take pressure off the wound, allowing more rapid healing.(2)
Deep burns may take several weeks to fully heal. When the dog’s bandages are removed, exercise should be reintroduced gradually, beginning on soft surfaces. Protective booties may also be helpful when the bandages are initially removed, to provide a more gradual transition to unpadded walking. Gradually, the pad will regain its toughness and normal activity can be resumed.
Heatstroke
Heatstroke is another common summer emergency in vet clinics across the country. Heatstroke cases often involve dogs exercising with their owners, left outdoors with inadequate access to water and shade, or left in a car unattended. Heatstroke can affect any animal, but it most commonly affects dogs with brachycephalic conformation, laryngeal dysfunction, obesity, advanced age, or neurologic conditions.(3)
Heatstroke is typically diagnosed on the basis of an elevated body temperature (often exceeding 106°F), but it’s important to note that a normal or low body temperature does not rule out heatstroke. In many cases, the owner has already begun trying to cool the pet before arriving at the vet clinic. Therefore, it is very important to obtain a thorough history in any pet suspected of having heatstroke!
Other clinical signs of heatstroke include weak or bounding pulses, labored breathing, tachypnea, and brick-red mucous membranes. Elevated internal temperatures may trigger massive inflammation, widespread vasodilation (with resulting changes in blood pressure), myocardial damage, pulmonary edema, gastrointestinal ischemia, liver and kidney damage, and disseminated intravascular coagulation (DIC).(3)
The first step in treating heatstroke is to actively cool the patient. Recommended cooling methods include lukewarm water, fans, and cool water enemas. These cooling measures should be continued until the pet’s temperature reaches 103°F, then halted to prevent hypothermia. Avoid ice baths, because they trigger vasoconstriction and can inhibit cooling.
As the patient begins to cool down, your focus must shift to the prevention and correction of internal organ damage. Place an IV catheter and administer fluids to aid organ and tissue perfusion. Perform a complete blood cell count and serum biochemistry, to determine whether dextrose or electrolyte supplementation are required. If secondary effects of heatstroke occur (such as seizures, upper airway swelling, or arrhythmias), these should be addressed with appropriate medications. Antibiotics may also be administered, in order to minimize bacterial translocation risks in a compromised gut.(3)
Even with aggressive treatment, the mortality rate for canine heatstroke is approximately 50%.(4) Owners should be informed of this guarded prognosis before aggressive treatment is initiated, so that they can enter into treatment with realistic expectations.
With any luck, you’ll experience a relaxing summer free of these particular emergencies. If you see these cases, however, remain calm and approach them systematically. Aid the patient to the best of your abilities and review these cases with your mentor, discussing treatment decisions and case outcomes. Doing so will allow you to assist the pets in your care while also gaining valuable knowledge that can be used to treat future patients!
Resources
- Berens J. 1970. Thermal contact burns from streets and highways. JAMA. 214(11):2025-7.
- Amalsadvala T. 2002. Paw tissues unique; injuries need special care, attention. DVM360.
- Marshall M. 2008. Heat stroke: diagnosis and treatment. DVM360.
- Bruchim Y, Horowitz M, Aroch I. 2017. Pathophysiology of heatstroke in dogs - revisited. Temperature (Austin). 4(4):356-370.