Diabetes in Dogs: Symptoms, Treatments and Dietary Management

Diabetes mellitus, sometimes called sugar diabetes, is a common disease in dogs. Golden Retrievers, German Shepherd Dogs, Miniature Schnauzers, Keeshonden, and Poodles have the highest incidence, but all breeds can be affected. Females with the disease outnumber males by three to one. The average age of onset is 6 to 9 years.

Diabetes is a result of inadequate production of insulin by the islet cells in the pancreas. There may be a genetic predisposition for this in some dogs. Islet cell destruction also occurs in some cases of pancreatitis. Insulin enables glucose to pass into cells, where it is metabolized to produce energy for metabolism. Insulin deficiency results in hyperglycemia (high blood sugar) and glycosuria (high urine sugar). Glucose in the urine causes the diabetic animal to excrete large volumes of urine. In turn, this creates dehydration and the urge to drink large amounts of water.

Initially, dogs who do not metabolize enough sugar have an increase in appetite and a desire to consume more food. Later, with the effects of malnourishment, the appetite drops.

In summary, the signs of early diabetes are frequent urination, drinking lots of water, a large appetite, and unexplained loss of weight. The laboratory findings are high glucose levels in the blood and urine.

In more advanced cases there is lethargy, loss of appetite, vomiting, dehydration, weakness, and coma. Cataracts are common in diabetic dogs. Ultimately, diabetes is a disease that affects all organs. Diabetic dogs will have enlarged livers, be susceptible to infections, and often develop neurological problems if not treated.

Diabetic ketoacidosis isa condition associated with severe hyperglycemia in which ketones (acids) build up in the blood. Ketones are byproducts of the metabolism of fat. In diabetic ketoacidosis, fats are metabolized for energy because sugar is unavailable. Diabetic ketoacidosis can be recognized by weakness, vomiting, rapid breathing, and the odor of acetone on the breath (it smells like nail polish remover). Diabetic ketoacidosis is a life-threatening emergency. If you suspect diabetic ketoacidosis, take your dog at once to the veterinarian.

Treating Diabetes

Dietary control and daily injections of insulin can regulate most diabetic dogs, allowing them to lead active, healthy lives. Oral hypoglycemic agents used for treating diabetes in people have not been effective in dogs, but research is continuing in this area.

Insulin requirements cannot be predicted solely on the basis of the dog's weight, because the degree of pancreatic failure is different in every dog. The daily insulin dose must be established for each individual. In the newly diagnosed diabetic, insulin therapy is started at home. After a week of treatment, the dog is brought back to the clinic and a blood glucose curve (a series of blood sugar tests drawn over 12 to 24 hours) is obtained to see when the blood glucose peaks and hits its lows. Refinements are then made in the dosage and timing of the injections. How to prepare and inject the insulin will be explained to you by your veterinarian. You may be asked to monitor urine glucose levels by collecting urine samples and using a test strip (a small piece of paper that indicates the glucose levels in urine).

Dietary Management

Obesity greatly reduces tissue responsiveness to insulin and makes diabetes difficult to control. Accordingly, an overweight diabetic dog should be put on a high-fiber, high-carbohydrate diet until he reaches an ideal weight. Examples of such diets are Hill's Prescription Diets r/d and w/d, Purina OM, and Fit and Trim Dry. Avoid soft-moist foods and treats, which are high in sugar.

Hyperglycemia is less likely to occur if the dog is fed canned and dry kibble foods containing high concentrations of fiber and complex carbohydrates. Both of these components slow absorption and help minimize fluctuations in blood sugar after eating. Some commercially available diets meeting these requirements are Hill's Prescription Diets w/d and r/d (canned and dry), Purina OM, and Fit and Trim Dry.

Daily caloric requirements are determined by the weight and activity level of the dog. Once those are established, the amount to feed is determined by dividing the daily caloric requirement by the amount of calories per cup or can of food. It is important to keep the number of calories constant from day to day, because insulin requirements are computed on that basis.

It is equally important to maintain a strict schedule for insulin injections. To prevent severe hyperglycemia after eating, do not give all the day's calories at one sitting. Divide the ration into equal parts and feed two or three meals a day, or as directed by your veterinarian. Diabetic dogs do best on a very regimented schedule with feedings and insulin injections being given at the same times each day. Ideally, your dog should have the same levels of exercise and activity.

A thin dog who has lost weight should be fed a low-fiber diet (low-fiber diets have higher caloric density) such as Alpo Light (canned) or Iams Less Active (dry) until weight is regained.

This article is excerpted from “Dog Owner’s Home Veterinary Handbook” with permission from Wiley Publishing, Inc.