Health

Wounded by Wildfires

Burns have causes beyond wildfires and are seen with some regularity by veterinarians

February 14, 2020 (published)
A wombat dubbed "Bernie" was treated in Australia after being burned in the wildfire. Bernie was treated for burns to his ears, which required removing some ear tissue. Bernie also has less serious burns on his face and near his paws. Photo courtesy of VIN News Service by Ross Kelly.

If your pet gets burned, prompt care provides the best chance for the least painful and extensive care. The faster you can get your pet to the hospital, the better.

Wildlife have no such luck.

Short of being found and moved immediately after injury, wildlife may languish in significant pain waiting for a human to find them and help. They may or may not survive.

The recent unprecedented bushfires in Australia took a shattering toll on the country’s impressive biological diversity. Rough estimates are that more than a billion animals lost their lives. Many were lucky enough to have survived and been treated by veterinarians, some of whom came from across the world to help save wildlife.

These fires altered the gene pools for some hard-hit plant and animal species, a phenomenon called population bottleneck.

Their homes are gone. Once these animals have recovered from burn wounds, smoke inhalation, or other wildfire-associated injuries, they have no choice but to brave the stress of rehoming and developing new familial structures. For them, after medical recovery the road to normal life will be anything but easy.

Burn wounds have multiple causes beyond wildfires and are seen with some regularity in veterinary hospitals. Heating pads and chewing on electrical cords causes burn wounds. Even excessive sun exposure and walking on hot sidewalks or asphalt can result in burns that require care by a veterinarian. In hot months, dogs may even be burned during outdoor bathing. If the garden hose laid in the sun too long, the first water out of it can be hot enough to cause a burn. Regardless of cause, burns may not become obvious for several days. Even the first signs of a burn, such as pain and hardening of the dead skin, may go unnoticed.

Thermal (heat) burns cause tissue destruction due to clots forming within vessels and damage to proteins that support the skin’s normal structure. This results in breakdown and loss of the normal architecture of tissue in a process called coagulative necrosis, a type of tissue death.

It’s similar to widespread drought causing river and creek beds to dry up with loss or relocation of the plants and animals that depend on the water they carry. Part of the reason burns are capable of causing tissue death is because they can permanently disrupt normal flow of blood through skin and the tissue beneath it. While death of tissue is not reversible, given time and the right treatments, skin typically can regrow.

There are four levels of burns ranging in severity from first- to fourth-degree. First-degree burns, which are the least severe, only affect the skin’s top layer, the epidermis, and heal more rapidly than the others. Fourth-degree burns, the most severe, extend to the tissue beneath the skin’s dermis layer and can result in the loss of a toe or even a limb. Some of the worst burn wounds I’ve encountered have come from nearby wildfires.

Wound Healing and Care

After an animal has been rescued from a fire, pain from the burn should be treated along with any other complicating conditions. Fluids given by IV treat dehydration and shock while antibiotics are given when there is concern for infection.

Hair or fur should be clipped away, leaving a wide border around the burn’s edge. Because hair is normally contaminated with bacteria, hair within a wound prevents adequate cleaning and predisposes the area to infection. When clipping hair away, the burn will often end up being larger than originally believed because hair can hide part of it.

Dead tissue should be removed to reveal the wound bed below, where a type of tissue called granulation tissue will grow. It has a red, granular appearance and is proof the skin is regenerating. Granulation is the part of the healing process in which uneven pink tissue forms around the edges of a burn wound (or any wound); it contains new connective tissue and capillaries. It functions as a scaffold for new skin cells to grow and spread out into the wound from the healthy skin-wound border in a process called epithelialization.

Painful animals will be placed under anesthesia for early wound care and bandaging. Removing dead tissue is an important step in early wound care, as it too harbors bacteria. Methods of removing it include hydrotherapy and surgery. Hydrotherapy rinses the wound with a cleansing solution such as sterile water or saline. Medications, such as honey or creams containing silver and antibiotics, are often applied to the wound to prevent bacterial infection and provide moisture to aid in skin regeneration. A new strategy being used for its ability to help healing of animal burn wounds is bandaging with fish skin.

When Healing Stops

When a burn wound has healed as much as it’s going to on its own, surgery can be done. The type of surgery will depend on the size and location of the wound.

A tension-releasing wound closure, similar to a punch graft, can be used for small wounds that have stopped healing. This wound was not caused by a fire, but is a good example of a tension-releasing wound closure. Photo by Dr. Teri Ann Oursler.

Punch grafting, similar to a tension-releasing wound closure, can be used for small wounds that have stopped healing. It’s a bit like taking a potted plant out of the pot and planting it outdoors. Punch grafting first removes, or harvests, small healthy pieces of skin from the patient. The veterinarian then cuts small similarly shaped divots into the granulation bed, and places the new healthy skin into the divots. These will be secured with a bandage. Eventually these new skin pieces, like the roots of a plant growing into new soil, will grow into the wound bed and send out new skin cells along their edges, filling the gaps where no skin exists.

Another surgical strategy for large wounds entails partially removing a much larger piece of healthy skin from around the burn. A healthy section of skin is cut out on three sides, in a shape identical to the wound. The fourth side remains uncut and attached. Next, it is lifted up and placed into the wound, like the last piece of a puzzle sliding into place. Finally, the healthy transplanted portion of skin will be secured in place with sutures. Having part of its original connection with the rest of the skin allows for its existing blood supply to help support it in its new home.

One important factor veterinarians must consider with wildfire victims is if there are any unseen injuries. Smoke inhalation causes injury to respiratory organs. Patients with airway or lung injuries may be in need of hyperbaric oxygen therapy. This treatment requires placing the animal in an airtight enclosure with an increased level of oxygen. Hyperbaric oxygen therapy is also used for healing burn wounds when extra assistance is needed.

Animals look for places to hide during a wildfire. If they were unable to run away from the flames, they can sometimes be found in crawl spaces beneath homes. Displaced animals can be injured while they are trying to escape the fire and may even have predator-related injuries.

Some animals may not have had food or water for days when they come into the hospital. Food is fuel for wound healing, which makes nutrition one of the most important considerations when optimizing conditions to help burn wounds heal. It may be necessary to change the type of food or increase the amount being fed to maximize the speed of healing and counteract the loss of protein-rich fluid that seeps from burn wounds.

Pain will eventually subside but the use of more than one pain medication is common for severely burned patients. Signs of pain may be vague and include excessive panting, lack of appetite, and lack of interest in the normal daily routine (e.g., going on a walk). Severe pain may be associated with hiding or not wanting to get up and move around.

Should you find your pet has a burn from any source ‒ wildfire, kitchen fire, boiling water, heating pad, hair dryer ‒ don’t delay taking them to the veterinarian. Third- and fourth-degree burns are emergencies. If you notice behavior changes afterwards, ask your veterinarian about improving pain control.


VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email news@vin.com.



Information and opinions expressed in letters to the editor are those of the author and are independent of the VIN News Service. Letters may be edited for style. We do not verify their content for accuracy.




 
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