Diabetes mellitus is a disease where the patient is unable to control its own blood sugars (glucose) and is similar when compared between dogs, cats and humans. Insulin is crucial to move glucose from the blood into the tissues of the body where it is used for energy. The problem with diabetes is that the body either doesn’t produce enough insulin (Type I, or insulin responsive) or the body doesn’t recognize the insulin that is being produced (Type II, or non-insulin responsive). When the body’s tissues don’t receive glucose they are forced to utilize other resources for energy.
The first energy resource to be used is fat because it has the next highest energy density. In diabetes mellitus the glucose remains in the blood and is not distributed to the tissues, so the body breaks down fat for energy and the patient begins to lose weight. Because the blood sugars are so high the kidneys allow some of it to spill into the urine, so the urine becomes sticky. The high amount of sugar in the urine triggers the patient to drink more in an attempt to dilute the excessive sugars in the blood and urine. In summary, the classic signs of diabetes are weight loss (despite a good appetite), sticky urine, and excessive drinking and urinating. In addition, dogs will commonly develop cataracts making their eyes appear blue, which is an irreversible change within the lens of the eye. Cats tend not to develop cataracts like dogs.
Treatment for diabetes usually includes increasing exercise, changing to a specialized diet, and insulin injections. Insulin is a protein that would be degraded by the stomach if given orally, so it has to be given as an injection. There are many types of insulin, some are given once daily and most are to be given every 12 hours after a meal. Diabetic diets consist of high fiber and low carbohydrate foods which in many cases are prescription diets. Exercise is a natural way to help drive glucose from the blood into the body’s tissues, and with increased exercise we are often able to decrease the insulin dose. Insulin metabolism varies with each individual. Cats can even have “transient diabetes” where they are diagnosed with diabetes, but over a short time period the insulin can be reduced and even discontinued in some cases if diagnosis and initiation of treatment occurs early enough.
If a patient has been diabetic for a period of time without treatment they can develop a fatal condition called diabetic ketoacidosis (DKA). In this situation toxic acids accumulate as a result of the breakdown of fat for energy. These acids put serious strains on the body and if the acidic condition of the body is not corrected quickly serious complications can occur including irreversible tissue damage, coma, and even death. Dogs diagnosed with DKA are usually hospitalized on fluids, insulin, and other medications until hydration status and acid/base balance is reestablished.
If you notice any of the classic signs of diabetes in your pet (weight loss, increased drinking and urinating, sticky urine, blue eyes for dogs) you should contact your veterinarian and bring your pet in for an exam, bloodwork and urinalysis to test for diabetes mellitus.