Blood sugar, or glucose, is a dog’s primary energy source. Normally, a dog’s body regulates blood sugar through insulin, a hormone produced by the pancreas. 

Hyperglycemia in dogs is a condition where their blood sugar gets abnormally elevated. While a temporary increase in blood sugar is not that serious, consistently elevated glucose levels can be concerning. This might be an indicator of a serious medical condition, such as diabetes or pancreatic issues.

If hyperglycemia in dogs is left untreated, it can worsen and spiral. This results in severe consequences that may negatively affect a dog’s overall well-being.

To prevent that, we’re filling you in on everything you need to know about hyperglycemia in dogs.

How Does Hyperglycemia in Dogs Happen?

A healthy dog’s blood glucose levels typically range between 80 and 120 mg/dL. After eating, it is completely normal for blood sugar to rise temporarily, but it should return to normal within a few hours. If a dog consistently has blood glucose levels above 200 mg/dL, it may indicate an issue with insulin regulation. 

Insulin has a key role in maintaining stable blood sugar levels. When a dog eats, carbohydrates in the food are broken down into glucose. The pancreas then releases insulin, which aids in transporting glucose from the dog’s bloodstream into the cells, where it is used for energy. If something disrupts this process, the glucose remains in the bloodstream instead of being utilized. 

This ultimately leads to hyperglycemia in dogs.

What Causes Hyperglycemia in Dogs?

Hyperglycemia in dogs can occur for a variety of reasons. In some cases, it is a temporary response to stress, illness, or certain medications. However, in chronic cases, it typically indicates a health issue.

Here’s what causes hyperglycemia in dogs:

• Diabetes. Diabetes mellitus is the leading cause of hyperglycemia in dogs. It happens when the pancreas either does not produce enough insulin or the body’s cells reject the insulin. In dogs, Type I diabetes is the most common form, meaning they require lifelong insulin therapy. Usually, this is caused by genetics, age, or obesity. 
  
  

• Pancreatitis. The pancreas plays a part in insulin production. In canine pancreatitis, the inflammation can damage insulin-producing cells, leading to hyperglycemia in dogs. When things get worse, repeated episodes can increase the risk of diabetes.
  
  

• Hormonal Disorders. Certain hormonal conditions can interfere with insulin function and lead to elevated blood sugar levels. This includes Cushing’s disease, a condition where the dog’s body produces too much cortisol, leading to increased blood sugar and insulin resistance. 
  
  

• Medications. Some medications can cause temporary hyperglycemia in dogs, particularly if they affect insulin production or sensitivity. The most common drugs that can elevate blood sugar levels include corticosteroids, diuretics, and hormonal medications.
  
  

• Stress. In some cases, a dog’s blood sugar may spike due to stress, anxiety, or excitement. This is especially common during veterinary visits or in dogs with nervous temperaments. Stress-related hyperglycemia in dogs is usually temporary and resolves once the stressor is removed.
  
  

• Other Medical Conditions. Hyperglycemia in dogs can also occur as a secondary effect of other illnesses. This can be from liver disease, infections, and tumors affecting insulin production.

What are the Symptoms of Hyperglycemia in Dogs?

While mild situations might be hard to notice, consistently high blood sugar levels in dogs can result in changes in their behavior, energy levels, and health.

Here are the common signs of hyperglycemia in dogs: 

• Increased Thirst and Urination. Dogs with high blood sugar often drink excessive amounts of water. With increased water intake comes frequent urination. The dog’s body tries to flush out excess glucose through the urine. This ultimately leads to dehydration and a constant need for more water.
  
  

• Increased Appetite. Despite having high blood sugar levels, dogs with hyperglycemia may seem constantly hungry. This happens because their body is unable to properly use glucose for energy, making them feel as though they are in a state of starvation.
  
  

• Unexplained Weight Loss. Even though some dogs with hyperglycemia eat more, they may still lose weight. Without proper insulin function, the body is unable to store and use glucose effectively. So, more fat and muscle will be broken down for energy.
  
  

• Lethargy and Weakness. Dogs with high blood sugar often appear tired, sluggish, or less interested in activities they once enjoyed. Since their cells are not receiving the energy they need, they may seem weak or reluctant to move.
  
  

• Recurrent Infections. Hyperglycemia can weaken a dog’s immune system, making them more prone to infections. Infections in the urinary tract, ear, and skin will be common in dogs with diabetes or chronically high blood sugar levels.
  
  

• Vision Problems. One of the long-term complications of hyperglycemia in dogs, particularly in diabetic pups, is cataract formation. This can cause cloudy eyes and, over time, lead to partial or complete blindness.

  
  

• Vomiting and Diarrhea. In extreme cases, very high blood sugar levels can lead to nausea, vomiting, and diarrhea. If left untreated, hyperglycemia in dogs can progress to a life-threatening condition called diabetic ketoacidosis.

How is Hyperglycemia in Dogs Diagnosed?

Hyperglycemia is not a disease itself but a symptom of an underlying condition. This means that an elevated blood sugar level will tell you the health issue your dog is facing. 

To diagnose hyperglycemia in dogs, we begin with a simple physical examination. This step will involve identifying other accompanying symptoms so we’ll know what tests to do afterward. Your dog’s medication history will also be considered, as medications can sometimes cause high blood sugar levels in dogs. 

A blood test is the most reliable way to confirm hyperglycemia in dogs. We may run several blood tests to assess glucose levels and overall health. 

The common blood tests we use include:

• Blood Glucose Test. This test measures the glucose in the bloodstream. Normal blood sugar levels for dogs range from 80 to 120 mg/dL. A reading consistently above 200 mg/dL is typically the threshold for high blood sugar levels.
  
  

• Fructosamine Test. A fructosamine test shows an average blood glucose level over a time period. This test helps distinguish between temporary spikes in blood sugar and chronic hyperglycemia, which is common in diabetic dogs.
  
  

• Complete Blood Count and Biochemistry Panel. These tests assess overall organ function and help rule out conditions like pancreatitis, infections, or hormonal imbalances.

Additionally, a urine test is often performed alongside blood tests to check for glucosuria, which is the presence of glucose in the urine. Dogs with consistently high blood sugar will often have excess glucose spilling into their urine. 

If hyperglycemia is confirmed, additional tests may be necessary to determine the cause. This can include hormone testing, pancreatic function tests, and imaging techniques. Once we know what caused your dog’s hyperglycemia, we can proceed to treatment. 

How to Treat Hyperglycemia in Dogs?

In most cases, this involves a combination of medication, diet, exercise, and regular monitoring. The main treatment plan will vary depending on the cause of your dog’s hyperglycemia.

Insulin Therapy for Diabetic Dogs

For dogs diagnosed with diabetes mellitus, insulin therapy is the primary and most effective treatment. Since most diabetic dogs develop Type I diabetes, their bodies do not produce enough insulin, making lifelong insulin injections necessary. You will be taught how to give injections at home. A schedule must be followed to make sure that your dog’s blood sugar levels remain stable.

Skipping insulin doses can lead to dangerous spikes in blood sugar, while overdosing can cause hypoglycemia. Regular visits will be important to monitor your dog’s condition. With every checkup, we’ll adjust your dog’s treatment plan and recommend the appropriate changes.

Dietary Management

Diet is an important part of the treatment process, especially for diabetic dogs or those with insulin resistance. A well-balanced diet should be low in carbohydrates and high in fiber, as fiber slows glucose absorption. This also helps maintain steady blood sugar levels throughout the day. 

Prescription diets will be a big help in this process. Many formulated foods cater to diabetic and hyperglycemic dogs. Meal timing is also as important as the food itself. Feeding your dog at the same times every day will help prevent too many blood sugar fluctuations. It’s also good for making sure that the insulin is working properly.

Exercise and Lifestyle Adjustments

Regular physical activity helps improve insulin effectiveness and prevents weight gain. Moderate exercise, such as daily walks or light play sessions, can support overall dog health. However, it’s important to maintain a consistent level of activity. A sudden increase will cause blood sugar levels to drop excessively. Also, diabetic dogs should avoid excessive or intense exercise.

Treating Underlying Conditions

If your dog’s hyperglycemia is caused by a condition other than diabetes, treatment will focus on resolving that specific issue. In cases of pancreatitis, management involves a low-fat diet, pain control, and supportive care to allow the pancreas to heal.

For dogs with Cushing’s disease, medications to regulate hormone levels will help. In some cases, surgery may be recommended. If a dog’s hyperglycemia is linked to medications such as corticosteroids, our vets may adjust the dosage or explore alternative treatments. Lifestyle and home adjustments will be recommended for stress-related hyperglycemia.

How to Prevent Hyperglycemia in Dogs?

Preventing hyperglycemia starts with regular vet checkups, a healthy diet, and consistent exercise. 

1. Schedule Checkups. Routine blood tests help detect early signs of diabetes and other conditions before they become serious.
   
   

2. Manage Your Dog’s Weight. Keeping your dog at an ideal weight reduces the risk of insulin resistance and diabetes.
   
   

3. Keep a Balanced Diet. A low-carb, high-fiber diet helps regulate blood sugar and prevents glucose spikes.
   
   

4. Limit Treats and Table Scraps. Avoid sugary snacks and high-fat foods that can contribute to weight gain and insulin resistance.
   
   

5. Monitor Medications. Some drugs, like corticosteroids, can raise blood sugar and should only be used under veterinary supervision.
   
   

6. Manage Stress. A calm environment and consistent routine can help prevent temporary spikes in blood sugar.
   
   

7. Address Health Issues. Addressing infections, pancreatitis, and hormonal disorders can prevent secondary hyperglycemia in dogs.

When we understand our pets' needs, we give them the best chance at a long, happy life.

- Dr. Soheyl Simaei

Conclusion

Hyperglycemia in dogs is often a sign of another health condition that requires our attention. Whether it’s diabetes, pancreatitis, or hormonal imbalances, high blood sugar levels in dogs should always be addressed. 

The good news is that dogs can still lead happy lives with proper care and management. A few lifestyle changes should do the trick. It just takes a lifelong commitment to keep our dogs happy and healthy.