By: Cate Burnette

Is your pet suddenly losing weight, yet continuing to eat normally? Is she having accidents in the house, or needing to go outside more often to urinate? Is the litter box full of urine more than is usual for your cat? If you’re noticing these behaviors in your dog or cat, seeing your veterinarian may be crucial for your pet’s health. She may have developed diabetes mellitus.

Diabetes and Its Causes

Diabetes mellitus is a disease in which certain cells of your pet’s pancreas either stop producing the insulin hormone or no longer produce it in enough quantity to fulfill the needs of the animal’s body. Insulin converts glucose (carbs and sugars) in the muscles and organs to energy, and without that conversion, excess glucose is carried out of the body in urine.

There are several possible causes for diabetes mellitus. Genetic predisposition is one likely cause, since some canine breeds seem to be predisposed to diabetes, and dogs that have diabetes often also have relatives with it. There appears to be no breed predisposition amongst cats; however, a higher incidence of feline diabetes in Burmese cats has been reported in Australia and the UK.

There is also thought to be a relation to hormonal therapies; due to the drugs’ interference with insulin production, dogs that are receiving medications to control heat cycles are at a higher risk for developing diabetes.

A correlation between the parvovirus in puppies, canine distemper, and pancreatitis in adult dogs and cats and the onset of diabetes has been noted in some veterinary studies. All three diseases are known to destroy the pancreatic cells used to manufacture insulin leading to a resultant lack of the hormone that causes diabetes.

Symptoms of Diabetes

An affected animal will be hungry a lot of the time. Since glucose is not making it to the brain, the levels are too low for the brain to register that it is receiving food. You’ll see an increase in appetite, yet your pet will continue to lose weight because the nutrients in her food are not staying in her body. With glucose constantly leaving the body, she will be tired and unable to exercise or play. There is also increased thirst as a result of an upsurge in urine output while the body attempts to rid itself of the excess insulin.

The liver can also be adversely affected by this condition, as can the eyes and kidneys. Many animals with chronic and/or untreated diabetes will develop cataracts in their eyes and eventually go blind. They may also develop chronic kidney disease.

Risk Factors for Diabetes in Pets

The typical canine patient is female, overweight at diagnosis, and middle-aged, however, diabetes can occur at any age. Breeds at a higher risk of developing diabetes include the Keeshond, the Puli, Miniature Pinschers, Samoyeds, Cairn terriers, Poodles, Dachshunds, Miniature Schnauzers, and Beagles.

While diabetes can affect all cat breeds, high risk factors for the disease include male gender, increasing age, physical inactivity, obesity, medicating with steroids and the ingestion of high carbohydrate foods.

Types and Rates of Diabetes in Pets

This condition is commonly divided into two types, depending on the origin of the condition. Type 1 diabetes, called “juvenile diabetes” in humans, is caused by destruction of the beta cells of the pancreas that manufactures insulin. All diabetic dogs have this type of diabetes. In Type 2 diabetes, insulin is produced but the body does not respond properly to it. Type 2 diabetes is also called “insulin resistance” and is the most common form of diabetes in cats and people.

Diabetes Type 1 is said to strike 1 in 500 dogs. The number of dogs diagnosed with diabetes mellitus has increased 300 percent in the past 30 years in this country. Survival rates from almost the same time period show that only 50 percent of affected dogs survived the first 60 days after diagnosis and went on to be successfully treated at home. This leads one to believe that diabetic symptoms in dogs are often overlooked and untreated until it is too late to save the animal. Current studies show that diabetic dogs receiving daily insulin treatment have the same expected lifespan as non-diabetic dogs of the same age and gender.

According to Dr. Donna Spector, veterinary consultant for Halo Pets, feline diabetes (Type 2) affects one out of every 100 cats – approximately 800,000 pet cats in the US. Decreased physical activity, feeding food high in carbs, and obesity are the most common causes of this disease in cats.

Veterinary Diagnosis and Treatment

In order to make a complete diagnosis, your veterinarian will take detailed a medical history from you about your pet’s health leading up to the onset of symptoms. The vet will also want details of the exact symptoms, including an estimation of daily urination times and amounts. Standard tests commonly include a complete blood count, chemical profile, and urinalysis. These tests should be sufficient for diagnosis and initial treatment.

Typically, with diabetes, an unusually high concentration of glucose will be found in your pet’s blood and urine. Abnormally high levels of liver enzymes and electrolyte imbalances are also common. Urine test results may also show evidence of abnormally high levels of ketone bodies – water-soluble compounds produced as a by-product of fatty acid metabolism in the liver and kidney. A numbers of other abnormalities may also be found.

The course of treatment for both cats and dogs typically includes…

  • Daily exercise using walks, runs or play therapy.
  • Gradual weight loss through increased physical activity and lowered caloric and carbohydrate intake.
  • Veterinary dietary management plans for all foods and treats. Dr. Spector recommends feeding cats “a canned, high protein, low carbohydrate food twice daily.” The veterinarians at WebMD suggest giving a high-fiber veterinary diet designed to normalize blood glucose levels.
  • Determination and tracking of daily blood glucose levels.
  • Daily insulin injections depending on the size, age, gender and weight of the affected animal. The insulin dosage may need to be adjusted as blood glucose levels sometime vary from day to day.

If left untreated, diabetes can lead to cataracts, growing weakness in the legs, malnutrition, vomiting, dehydration, and the development of ketoacidosis. Ketoacidosis is a metabolic process where fats and proteins in your pet’s liver are broken down to serve as sources of energy not being supplied by necessary glucose. This leads to chronic liver disease, and eventually liver failure and death.

Prognosis of Pet Diabetes

Unfortunately, diabetes is not a disease that can be cured, but your pet’s health can be kept stable and she can go on to live a fully enjoyable life. This will be dependent on your willingness to adhere to your veterinarian’s dietary recommendations and suggested insulin protocol. The best preventive from complications is practicing careful maintenance at home with your animal’s best life in mind.


Cate Burnette is a semi-retired registered veterinary technician with clinical experience in small and large animal medicine. With 30-plus years of journalism experience, she went back to school after 9/11 to work with her first love: animals. The pet parent of four cats, three dogs and one ex-racehorse, Cate is a certified rescue volunteer with the American Humane Association’s Red Star Emergency Services and served with the group in New Orleans doing animal search and rescue after Hurricane Katrina. She is also a horse safety and horse management expert, and has volunteered with US Pony Clubs as a district commissioner and horse management judge.

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