- Hyperglycemia is typically caused by an insulin issue — High blood sugar occurs when a dog’s body isn’t producing enough insulin or the insulin isn’t working correctly to metabolize glucose.
- A normal dog’s blood sugar is between 75 and 120 milligrams (mg) — While glucose levels can rise during stressful times — like a blood draw at the vet clinic — a healthy dog’s glucose shouldn’t be over 120.
- Hyperglycemia can cause the 3 P’s in your dog — The 3 P’s, known as polydipsia (excessive thirst), polyuria (excessive urination), and polyphagia (excessive hunger), are common signs in dogs with high blood sugar.
- Hyperglycemia in dogs can be caused by many health issues — Diabetes and pancreatitis are some of the most common conditions that raise blood sugar. Infections and diseases that increase glucose production can also occur.
- Treating high blood sugar depends on the cause — Hyperglycemia isn’t always caused by diabetes. So, giving your dog insulin won’t always be the solution.
High blood sugar in dogs
High blood sugar is also known as hyperglycemia, meaning a dog has abnormally high levels of glucose (sugar) in their blood. When the glucose levels rise, like after eating or during stress or activity, insulin is released into the bloodstream to help maintain normal sugar levels.
Insulin is a hormone that’s produced by a dog’s pancreas and transports glucose from the bloodstream to the cells. Glucose is the main source of energy for the body’s cells. Low insulin levels can lead to high blood sugar, as can the body’s inability to properly use insulin.
Signs your dog’s blood sugar is high
Since hyperglycemia can have several different causes, your dog may exhibit a variety of clinical signs. If the cause is temporary, like stress or after eating, you likely won’t notice any issues. However, hyperglycemia caused by a chronic condition such as diabetes or Cushing’s disease can lead to noticeable symptoms. Some of the more common signs that mean your pooch has high blood sugar include:
- Increased thirst (polydipsia). When glucose overflows into the urine, it takes large volumes of water with it. Dogs with high blood sugar usually drink a ton, so an empty water bowl may mean your pup has hyperglycemia.
- Increased urination (polyuria). All that extra water your dog is drinking has to go somewhere, so they’ll be heading outside to urinate more frequently and in larger amounts. They may also start having accidents in the house.
- Excessive hunger (polyphagia). Since glucose can’t be transported properly into the cells for energy, your dog may feel like they’re starving. In an attempt to find a source of energy, your pup may eat much more than normal.
- Dehydration. Even if your dog is drinking more than usual, the glucose in their bloodstream is pulling excessive amounts of water with it as it spills into the urine. Your pet may be unable to keep up with this water loss and become dehydrated.
- Weight loss. Despite a voracious appetite, you may notice your dog losing weight when they’re hyperglycemic. Since there’s not enough glucose being transported into the cells, the tissues become starved for energy. So, the body breaks down fat and muscle tissue for fuel.
- Obesity. In obese dogs, cell receptors don’t realize glucose is a source of energy. As more and more insulin is required for them to understand it, the insulin-producing cells in the pancreas are depleted and diabetes develops.
- Cataracts. About 80% of diabetic dogs develop cataracts, an opacity in the lens of the eye. Normally, the lens absorbs sugar to use as energy, but excess sugar pulls water into the lens, disrupting clarity and causing a cataract to form.
- Severe depression. Lethargy and depression generally occur when blood glucose levels are very high, or when a life-threatening condition called ketoacidosis happens.
- Chronic or recurring infections. As the excess sugar feeds bacteria and fungi, your dog may develop non-healing wounds, chronic skin infections, or recurring urinary tract infections.
- Tissue damage. Sugar within the body’s tissues has an oxidizing effect that can burn affected areas.
🚨 If you notice any of these signs in your dog, you should take them to a vet immediately.
Common causes of high blood sugar in dogs
While you may think the only reason dogs have high blood sugar is diabetes, there are many other conditions that can elevate glucose levels. Some of the most common causes of hyperglycemia in dogs include:
- Diabetes. Diabetes mellitus occurs when a canine’s body can’t use glucose normally, whether there’s not enough insulin or the body is unable to use insulin.
- Pancreatitis. Acute or chronic inflammation of the pancreas can result in hyperglycemia. As the insulin-producing cells in the pancreas are destroyed, fibrous connective tissue takes their place, reducing the amount of insulin produced.
- Cushing’s disease. Cushing’s disease is another endocrine disease that results in the overproduction of the hormone cortisol in the adrenal glands. Cortisol raises blood glucose levels.
- High-stress situations. Stressful situations kick your dog’s fight-or-flight response into high gear, causing the bloodstream to be flooded with glucose for quick energy. Visits to your vet can cause elevated blood glucose, which may be misleading when trying to diagnose hyperglycemia.
- Infections. Dental and urinary tract infections are two of the most common infections that cause hyperglycemia in dogs. Infections make it more difficult for the body to use insulin. UTIs commonly occur in diabetic dogs, since their urine is more dilute and contains more sugar as a bacterial food source.
- Pregnancy. High progesterone levels can cause insulin resistance in pregnant dogs, contributing to hyperglycemia.
- Obesity. A cause of insulin resistance, obesity is one of the biggest (pun intended) driving factors of hyperglycemia in dogs.
- Long-term corticosteroid use. If your dog is on steroids for a chronic condition that requires immunosuppression, they can develop hyperglycemia because of inhibited insulin function.
Some dog breeds are more likely to have high blood sugar
While any pet can develop hyperglycemia, some dog breeds are more likely to have high blood sugar, including:
- Cairn terriers
- Miniature poodles
- Australian terriers
- Fox terriers
- Bichon frisés
Middle-aged and older dogs are more at risk for developing hyperglycemia, and it’s more common in female dogs than in males.
How is hyperglycemia diagnosed in dogs?
Based on your dog’s clinical signs, your vet will likely suspect hyperglycemia, but they’ll want to confirm their diagnosis. Diagnostic tests used to detect hyperglycemia include:
- Blood glucose level. A tiny drop of blood is all that is needed to determine how high your dog’s blood sugar is, which shouldn’t be over 120 mg. But, it can reach 180 mg in a stressful situation like a vet visit, but if it’s consistently that high, it confirms a hyperglycemia diagnosis.
- Urinalysis. A urinalysis will detect excess glucose in the urine, which spills over from the bloodstream if there’s too much. It can also tell if your dog has a UTI or other urinary issue that causes excessive thirst and urination.
Once your vet verifies that your dog has high blood sugar, they’ll recommend additional testing to determine the cause. They may suggest performing a complete blood count (CBC), blood chemistry panel, a lipase test, abdominal X-rays or ultrasound, or testing for Cushing’s disease.
Treatment for high blood sugar in dogs
Treating your dog’s high blood sugar depends on the condition causing it.
Diabetes mellitus treatment. If your dog has diabetes, they’ll be treated with a combination of daily insulin injections and diet modification. A diet low in fat and carbohydrates and high in protein and fiber may be recommended to help your dog maintain an ideal weight and glucose level. Diabetic treatment will be lifelong, with routine blood glucose curves and physical exams to see how your dog is metabolizing their insulin.
Pancreatitis treatment. If your dog is having a pancreatitis flare-up, they’ll likely need hospitalization to receive intravenous fluids, pain medication, and possibly antibiotics. A low-fat diet can help minimize future episodes. Keep in mind that pancreatitis can be a life-threatening condition, so get your dog to your vet immediately if you notice pancreatitis symptoms.
Cushing’s disease treatment. Most cases of hyperadrenocorticism are caused by a pituitary tumor. These cases generally respond well to one of several drugs that lower the body’s cortisol production. However, if your dog has an adrenal gland tumor, radiation or surgery may be needed instead. In either case, your dog will require lifelong treatment and periodic monitoring of their condition.
Steroid usage treatment. If your pup needs to be on steroids to manage another chronic condition, their dose may need to be adjusted, or another treatment option found to bring their blood glucose to a normal level.
Dietary management. If your dog’s blood sugar skyrockets after eating, you’ll need to find a lower-sugar diet that doesn’t affect their glucose level as much. Also, you’ll need to closely monitor how much your dog eats and measure out appropriate portions. No more filling the food bowl when it’s empty!
Stress management. Some dogs are highly sensitive to stress in their lives, which can cause hyperglycemia. Although high blood sugar may be temporary, it can cause detrimental effects on their body. Try to limit stressful situations as much as possible for your dog if they have stress-induced hyperglycemia.
🚨 Never attempt to lower your dog’s blood sugar abruptly. Hypoglycemia can prove fatal much more quickly than hyperglycemia can.
Prevention tips for pet parents
If your dog has diabetes or another condition that causes chronic hyperglycemia, here are some tips to help manage their high blood sugar:
Give your dog a special diet recommended by a vet — Prescription diets that are high in fiber and complex carbohydrates can help prevent major fluctuations in your dog’s glucose levels. Talk to your vet about the best diet for your pooch.
Follow your vet’s diet recommendations — Although your pup may be begging for your pizza crust or lick of your ice cream, excess fat, sugar, and carbohydrates can throw blood glucose levels out of whack. Ask your vet which foods are safe to give your dog as treats and stick to those. Also, be consistent when feeding your dog. Feed them the same food, same amount, and same treats at the same time each day to help regulate their blood sugar.
Never change your dog’s insulin dosage without consulting a vet — If your dog begins drinking and urinating excessively, they may have a problem other than hyperglycemia. Never adjust your dog’s insulin dosage without first consulting your vet, even if you check their blood glucose at home.
Have your female dog spayed — To avoid gestational diabetes in your female dog, or the potential for hyperglycemia during her heat cycle, have her spayed at the appropriate time.
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Stick to a daily exercise regimen — Exercising with your pooch every day can help them maintain a healthy weight and prevent obesity, a major cause of hyperglycemia.
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Frequently asked questions
What happens if a dog’s blood sugar is too high?
If your dog has high blood sugar, they’ll likely drink and urinate excessively. And, despite eating more, they may lose weight. In some cases, your dog will develop recurring infections, such as skin and urinary tract infections, or they may become extremely lethargic. If your dog’s blood sugar remains high without treatment, they can develop cataracts.
How can I lower my dog’s blood sugar?
First, your vet must determine why your dog’s blood sugar is high. If it’s because of diabetes, insulin and an appropriate diet can lower their blood sugar. Other conditions, like pancreatitis, infections, or Cushing’s disease, need to be treated first to help lower blood glucose levels. If your dog is diabetic and has a high blood sugar reading, never give them more insulin than your vet prescribed. Instead, schedule an appointment with your veterinarian before adjusting the dosage.
How do I know if my dog’s blood sugar is high?
A simple blood test can measure the glucose levels in your dog’s blood. A urinalysis can also be helpful, as it can detect excess glucose that has spilled over into the urine.
How long can a dog live with high blood sugar?
A dog who does not receive treatment for hyperglycemia will eventually go into ketoacidosis, a life-threatening condition that requires emergency treatment to correct. There is no timeline for this process, but, in general, a dog with untreated diabetes will pass within two to eight months after diagnosis.