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Maryland Dog Magazine

Diabetes Mellitus in Pets

Feb 13, 2015 07:57PM
by Dr. Bob A Cohn DMV

The cells of the body require a sugar known as glucose for food and they depend on the bloodstream to bring glucose to them.  They cannot, however, absorb and utilize glucose without a hormone known as insulin. This hormone, insulin, is produced by the pancreas. Insulin is like a key that unlocks the door to separate cells from the sugars in our  bloodstream.

Glucose comes from the diet. When an animal goes without food, the body must break down fat, stored starches, and protein to supply calories or energy for the hungry cells. Proteins and starches may be converted into glucose. Fat, however, requires different processing that can lead to the production of ketones rather than glucose. Ketones are another type of fuel that the body can use in a pinch but the detection of ketones indicates that something wrong is happening in the patient’s metabolism. Ketones may therefore be detected in the urine of starving animals because of the massive fat mobilization that is required for ketone formation.

In a diabetic animal there isn’t enough insulin. • The cells cannot receive glucose from the blood because there is no insulin to permit it. • The body is unable to detect the glucose in the blood and is fooled into thinking it is starving. • Protein, starch, and fat break-down occur as they do in starvation. • Yet all along there has been plenty of glucose in the blood. In fact, by now, there is a large excess of glucose as all resources have been mobilized. Still, without insulin, this bounty of fuel cannot get to the tissues that need it. • The normal kidney is able to preventglucose loss in urine. In a diabetic animal, there is so much glucose in the blood that the kidney is overwhelmed and glucose spills into the urine and is lost. • Glucose is able to draw water with it into the urine. This leads to excess urine production and excess thirst to keep up with the fluid loss.

Thus the main clinical signs of diabetes mellitus are: • Excessive eating • Excessive drinking • Excessive urination • Weight loss

It is usually fairly clear from the history and tests showing dramatic glucose elevations in the blood (and usually glucose in the urine, too) that diabetes mellitus is the diagnosis. In dogs, sugars can enter the lens of the eye causing rapid cataract formation. Because a cat’s lens is different, this phenomenon primarily occurs in dogs. Another common symptom of diabetes mellitus is urinary tract infection. All the sugar in the urine makes the bladder an excellent incubator for bacteria. Antibiotics are necessary to clear up such an infection and some monitoring may be needed to help detect these infections.

Type I and Type II Diabetes Mellitus Diabetes mellitus is a classical disease in humans and most of us have heard some of the terms used to describe it. In humans, diabetes is broken down into two forms: Type I and Type II. These are also referred to as juvenile onset and adult onset diabetes, or insulin dependent and non-insulin dependent diabetes. In short, Type 1 is the type where the pancreas produces no insulin at all, and in Type II the pancreas produces some insulin but not enough. Virtually all dogs get insulin dependent diabetes and must be treated with insulin. Most cats have non-insulin dependent diabetes. This might suggest that most cats can get away without insulin injections but that is not the case at all. Instead, for cats, there is potential for the diabetes to actually resolve if the pancreas improves its insulin-secreting ability. Insulin injections are needed to treat most diabetic cats but for some cats, the situation is mild enough for oral medication to suffice. Good glucose control and proper diet can resolve the diabetes in some lucky cats but virtually never in diabetic dogs. What Happens Once a Diagnosis Is Reached? First, an insulin type and dose will need to be selected. There are several types of insulin and it is not possible to know how much insulin your individual pet will require. Your veterinarian can make an educated calculation based on what works for other cats and dogs and what has been reported in the literature.  Most pets require injections twice a day, approximately 12 hours apart, following a meal.

Do we have to change our animals’ diet? In most cases, once the diagnosis has been made of Diabetes Mellitus, it is a good idea to consult your veterinarian about changing the diet for your pet. There are foods made for Diabetics that are mostly protein diets with little carbohydrates and fats, which should make maintaining control of the blood sugar levels easier. A food with more fiber is used more commonly in dogs since this too, reduces the amount of insulin required to maintain control of the blood glucose levels.

DR. BOB A COHN DVM, and President of North Laurel Animal Hospital in Laurel Md. Dr. Cohn studied veterinary medicine at Araneta University in Manilla, Phillipines. Dr. Cohn is a member of the American Veterinary Medical Association (AVMA), the American Animal Hospital Association (AAHA), the Eastern Veterinary Orthopedic Society (EVOS), the Veterinary Orthopedic Society (VOS) and the Maryland Veterinary Medical Association (MVMA). Dr. Cohn has also been a managing Board Member of the Emergency Veterinary Clinic in Catonsville, Maryland since 1990.

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