Diabetes in Dogs and Cats

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Diabetes is a complex and challenging disease. For pet parents, managing a diabetic pet can be even more complicated, since pets aren’t able to verbally communicate to us what’s happening in their bodies or how they’re feeling.

A diagnosis of diabetes for your dog or cat can be intimidating and scary. But it doesn’t have to be! Once you understand what causes diabetes, how it affects the body, and what steps to take to manage it, you’ll see that diabetes is a manageable condition that many pets can live with for the rest of their natural lives.

Although diabetes can affect almost any animal (including horses, birds, and reptiles), for the purpose of this article, we’ll keep things simple and reference dogs and cats only.

What is Diabetes mellitus?

Simply put, Diabetes mellitus is a disorder that occurs when the body doesn’t produce enough insulin. Insulin is necessary for our bodies to be able to efficiently use the glucose (sugar), fats and proteins that we consume as fuel.

Here’s how it works: Foods we eat are broken down into smaller components to be used by the body’s cells. One of these components, glucose, is our cells’ primary source of energy. In order for glucose to be able to get inside a cell, it first needs insulin to help.

Insulin, which is produced by the pancreas, attaches to specialized receptors in each cell and allows glucose to move out of the bloodstream and into the cell (think of insulin as the key that unlocks the door to the cell, allowing glucose to enter.) Without insulin, glucose can’t get inside the cell. So even if there is a large amount of glucose circulating in the blood, the cell begins to “starve”, and is forced to start breaking down stored fat and protein as its primary source of energy.

When this happens, the body’s metabolic process gets out of whack. When fat is burned for fuel instead of glucose, it creates organic acids called ketones. When too many ketones build up in the blood, a dangerous metabolic state called “ketoacidosis” occurs (more on that later).

In the meantime, when there is too much glucose in the blood, the body attempts to get rid of it by filtering it through the kidneys and flushing it out into the urine. In order to make more urine, the body needs large amounts of water, so the brain signals the body to drink more.

Since the body’s cells are unable to get enough glucose, appetite increases because the cells are literally starving. However, diabetic pets can’t properly use nutrients from food, so they lose weight even if they’re eating large quantities.

This whole sequence of events leads to the classic signs of diabetes: high levels of sugar in the blood and urine; the production of large amounts of dilute urine; feelings of intense thirst; and weight loss, despite a ravenous appetite.

Which Pets Are At Risk for Diabetes?

Obese pets and those with an inflammation of the pancreas (pancreatitis) are most at risk for developing diabetes. Some drugs can also lead to the onset of diabetes by interfering with insulin levels.

Cats are more likely than dogs to be diabetic (roughly 1 in 200 cats is diagnosed with diabetes, compared to about 1 in 500 dogs). Overweight, neutered male cats older than 5 years are most commonly afflicted. It’s in cats that obesity plays the biggest role: researchers have noticed a direct correlation between obesity in cats and an alarming increase in diabetes cases – the number of diabetic cats has increased fivefold over the last 30 years.

For dogs, it’s older, unspayed females who are more commonly affected. Genetic predisposition appears to play a larger role than obesity in diabetic dogs. Diabetes appears to be more prevalent in the Miniature Schnauzer, Keeshond, Poodle, Bichon Frise, Miniature Pinscher, Cairn Terrier, Spitz, and Samoyed. However, any dog can acquire diabetes.

Symptoms of Diabetes

Classic symptoms of diabetes include:

• Excessive urination (“polyuria”)
• Excessive thirst (“polydipsia”)
• Ravenous appetite
• Weight loss
• Lethargy
• Urinary tract infections (due to high levels of sugar in the urine)

If left untreated, as the disease progresses it begins to affect all organs in the body. Signs include:

• Refusal to eat
• Depression
• Vomiting
• Dehydration

You may hear your veterinarian use the term “PU/PD” when speaking about diabetes. This stands for “polyuria/polydipsia”, the most common symptom in diabetic pets.

Diagnosis

Diagnosis begins with observation at home. If pet parents are familiar with their pets’ normal patterns and behaviors, they’re more likely to catch the signs of diabetes in its early stages.

A diagnosis of diabetes is reached based on symptoms, physical exam and laboratory test results (including blood work and urinalysis), and the persistence of abnormally high levels of glucose in the urine and blood (ketones may also be present). Normal glucose levels range from about 80-120 mg/dl. Some diabetic pets may have extremely high levels of glucose reaching 500mg/dl or more.

Keep in mind that any cat may show a temporary increase in glucose on their blood work, but this does not necessarily mean they are diabetic. When cats get stressed (which happens whenever they go to the vet or have blood drawn), their blood glucose can shoot upwards of 300+ mg/dl! Fortunately, however, it goes back to normal when they are no longer upset. For a positive diagnosis of diabetes, glucose needs to be present in both blood and urine.

Once diabetes is diagnosed, it needs to be treated immediately.

Treatment for Diabetes

Treatment of diabetes involves 2 main components:

1. Administration of Insulin or Oral Medications

Insulin injections need to be given under the skin twice daily, immediately after the pet eats a meal, and preferably at the same time each day. These injections use very small needles, so most pets never even realize they’ve been given a shot.

An oral medication called glipizide, which lowers blood glucose, can sometimes be used in cats in place of insulin injections (however, insulin is usually much more effective). Glipizide is not very effective in dogs.

2. Dietary change

In diabetic pets, diet is just as important as insulin for helping to control blood sugar levels.  A diet high in fiber is slower to be digested and allows glucose levels to remain more stable.

Cats with diabetes reportedly do best on a high-fiber, high-protein, low-carbohydrate diet, but there is debate about which type of diet is best for diabetic dogs. Since every pet’s body responds differently to food, pet parents should work closely with their veterinarian to find a diet that is best formulated for their diabetic pet.

Since it’s vital for insulin to be given after each meal, diabetic pets cannot be allowed to eat whenever they want to. Meals should be only be given twice daily, and food intake needs to be closely monitored.

Potential Complications From Diabetes

Left untreated, diabetes can cause a whole host of complications and greatly shorten a pet’s lifespan.

Complications may include:

• Formation of cataracts in the eyes (more common in dogs)
• Bacterial bladder, kidney, or skin infections
• Fat accumulation in the liver, leading to liver disease
• Weakness in the hind legs or abnormal gait due to nerve or muscle dysfunction
• Kidney failure (caused by high levels of glucose that damage the filtering structures in the kidneys)

But by far the most dangerous complication of diabetes is a condition called ketoacidosis.

When the body burns fat and protein instead of glucose for energy, it produces acid compounds called ketones.  Normally, ketones in the body are filtered out by the kidneys, but if levels of ketones are very high, the body’s electrolytes become unbalanced and the pH of the blood becomes dangerously acidic.

Symptoms of diabetic ketoacidosis include weakness, lethargy, loss of appetite, vomiting and/or diarrhea, rapid breathing, and a fruity or “nail polish” smell to the breath.

Ketoacidosis is a medical emergency. If left untreated, it can lead to coma and death. If your pet is exhibiting signs of ketoacidosis, get to the veterinarian immediately.

Monitoring a Diabetic Pet At Home

Monitoring a diabetic pet requires consistency and vigilance. If you share your life with a diabetic pet, your veterinarian will partner with you to make sure that your pet’s blood glucose levels are carefully monitored.

Meanwhile, here are some tips for monitoring a diabetic pet at home:

1. Make sure you’re feeding your pet a consistent amount and administering insulin twice daily, and always at the same times each day.
2. Be constantly aware of your pet’s appetite, urine output, water consumption, and weight (weigh your pet every 2 weeks to monitor changes).
3. Keep diabetic cats indoors at all times.
4. Keep stress levels in your home low, as stress can affect blood sugar levels.

5. Monitor glucose in your pet’s urine using urine test strips. If your pet’s insulin levels are properly regulated, there should be no glucose present in his urine.
6. Watch for hypoglycemia! Hypoglycemia is low blood sugar, and it usually occurs from an overdose of insulin. In diabetic pets, hypoglycemia can be life-threatening.
7. Signs include weakness, lack of coordination, drooling, seizures, and coma. Keep corn syrup on hand to help correct hypoglycemia at home. You can rub it on your pet’s gums, or if your pet can swallow, slowly administer it by mouth with a syringe (but never attempt to give food or medication to a seizuring or unconscious pet). Then call your veterinarian immediately.

Living Successfully With Diabetes

Every diabetic pet is different. Some are easy to regulate with insulin, and some are more difficult. Regardless, every diabetic pet does best with a proper diet, consistent feeding and medication, and a low-stress lifestyle.

It’s important to note that some diabetic cats may actually lose the need for insulin months or years after their diagnosis (diabetes is rarely reversible in dogs, however). No one is sure exactly why this happens, but it can occur in some obese cats once their weight is brought under control.

However, if the diabetes does remain a life-long condition, keep in mind that a diabetic pet who is successfully managed with proper veterinary treatment and consistent home care can live a long, healthy and comfortable life.

Have you ever treated a diabetic pet? If so, do you have any tips or advice to share? Please tell us about it in the comments below!