It is officially my favorite time of the year! I am like a child during the Christmas season. I love the carols, the pretty packages, the trees, the lights! But most of all, I love the weather! I was made for cold weather and love snow more than anything else! While snowmen and snowball fights bring me joy, this kind of weather can be dangerous for my patients. So in preparation for the cold weather, I am going to talk about hypothermia and frostbite.
Hypothermia is defined as the condition of having an abnormally low body temperature. For my patients, this means a body temperature below 99*F. There are many causes of hypothermia. Certain diseases can cause it such as shock, but the most common cause during this time of year is from being left outside too long in the cold environment. The clinical signs of hypothermia depend on the severity of the hypothermia. They can range anywhere from shivering to muscle stiffness to coma and even death. There are a lot of complications that happen inside your pet that lead to these clinical signs. Let’s talk about those!
Metabolic Consequences: Your pet will become hypoglycemic (low blood sugar) that leads to weakness. This exacerbates the already lower metabolic activity in your pet’s cells (this also leads to more severe hypothermia). The potassium levels in your pet’s body alter during hypothermia which will cause problems with their heartbeat.
Cardiovascular Consequences: There are receptors on your heart that respond to adrenaline and tell it to beat faster. When your pet is hypothermic, these receptors become less responsive, so a very common clinical symptom is bradycardia (slow heart rate). Research shows that 50% of dogs in a hypothermic state will have cardiac arrhythmias (abnormal heartbeats) as well.
Respiratory Consequences: Hypothermia can lead to a decreased respiratory rate. It will also lead to something called a decreased tidal volume. This means that your pet will be taking more shallow breaths than usual. One reason this happens is because of the low metabolic rate in the body. This produces less Carbon Dioxide which tells the body it doesn’t need to breathe as much.
Neurologic Consequences: Hypothermia reduces the amount of blood flow to the brain. For every ~1.8 degrees lost in body temperature, the brain loses 6-7% of its blood flow.
This leads to derangements in mentation. These clinical signs can range from simple depression to coma. This also exacerbates the clinical symptoms because the brain is responsible for thermoregulation
Immune System Consequences: Something many people don’t think about with hypothermia is the effects on the immune system. Your pet will have a diminished resistance to infection as well as poor wound healing. This obviously predisposes them to an increased incidence of infection.
Those are a lot of scary consequences to hypothermia! As you can see, all of the complications exacerbate each other, so things can go downhill quickly. However, probably the scariest consequence to see is frostbite. Frostbite is defined as an injury to body tissues due to exposure to extreme cold that can lead to gangrene (necrosis and sloughing of the tissue). When a pet is left outdoors in the cold for too long, frostbite is a serious possibility. The most common places we see frostbite are the ears, nose, and paws. Frostbite is a serious issue that can result in surgery and long term medical management.
If you find an animal or if your pet is accidentally left outdoors too long, you need to take them to the veterinarian. Believe it or not, there are consequences that can happen if the rewarming is not done properly. You can actually send your pet into something called Rewarming Shock. We are absolutely the best option for these cases.
Please hear me say that I am not judging you if you leave your pets outdoors during the winter. But let’s just make sure that we do it in a safe way! Be sure that your pet has a shelter that has warm, hay bedding. It needs to protect them from the wind, snow, and rain. Be sure that they are of an adequate body condition (thin pets don’t handle cold as well), being fed adequate calories, and are a breed that can tolerate the cold (has a good coat with a thick undercoat). Be sure to constantly check on them and watch for signs like shivering, reluctance to move, ice on the coat, or a change in attitude. Also, be sure to always check your engine and above your tires – cold cats really like to climb up in those areas and hide.
As always, your veterinarian is only here to help! We will never judge and will help you and your furry loved one in any way we can! I hope you have a wonderful holiday season! Merry Christmas!
About the Author
Dr. Heritage Enevoldsen