Canine Diabetes Mellitus

Canine Diabetes Mellitus

There are two forms of diabetes in dogs: diabetes insipidus (drinking diabetes) and diabetes mellitus (sugar diabetes). Diabetes insipidus is a very rare disorder that results in failure to regulate body water content. Your dog has the more common type of diabetes: diabetes mellitus. This is a fairly common disorder and is most often seen in dogs 5 years of age or older. Diabetes mellitus is a disease of the pancreas. This is a small but vital organ that is located near the stomach. It has two significant populations of cells. One group of cells produce the enzymes necessary for proper digestion and the other group, called beta-cells, produce the hormone called insulin. Therefore, diabetes mellitus is a failure of the pancreas to regulate blood sugar.

Insulin allows glucose to leave the blood stream and pass into cells, where it provides much of the energy needed for life. Without an adequate amount of insulin, glucose is unable to get into the cells. It accumulates in the blood, setting in motion a series of events, which can ultimately prove fatal.

When insulin is deficient, the cells become starved for a source of energy. In response to this, the body starts breaking down stores of fat and protein to use as alternative energy sources. As a consequence, the dog suffers with weight loss and has a ravenous appetite. The body tries to eliminate the excess glucose by excreting it in the urine. However, the excess blood sugar attracts water, the urine glucose takes with it large quantities of the body’s fluids, resulting in the production of a large amount of urine. To avoid dehydration, the dog drinks large amounts of water.

There are four classic signs of diabetes:

  • Weight loss
  • Ravenous appetite
  • Increased water consumption
  • Increased urination

The diagnosis of diabetes mellitus is based on three criteria; the signs listed above, the presence of high level of blood glucose and the presence of glucose in the urine.

The normal level of glucose in the blood is 4 -7 mmol/l, however it can rise following a meal.

To prevent glucose loss from the body the kidneys only allow it to be filtered out of the blood stream when very high levels of glucose are circulating in the blood. This means that dogs with a normal blood glucose level will not have glucose in the urine. Diabetic dogs have excessive amounts of glucose in the blood, so it will also be present in the urine.


Blood glucose cannot be normalised without treatment, so the treatment should be looked upon as part of the dog’s daily routine. Treatment almost always requires some dietary changes and administration of insulin.

For the owner there are two implications: financial and personal commitment.

The financial commitment is significant during the initial regulation process and if complications arise. However, after the initial regulation the costs will decrease.

Should you wish to discuss any of these issues in more detail, please consult your veterinary surgeon.