Diabetes Mellitus
by Carla Douple, DVM
** Permission of author is required for use of this article.**

Diabetes is a common disease among humans as well as dogs and cats. Humans are susceptible to several types of diabetes related to age, obesity, genetics and insulin needs. Canine diabetics are almost always Type 1 insulin-dependent diabetics, but genetics and obesity can be factors in the disease.


The classic signs of a dog suffering from untreated diabetes include an enormous thirst and; therefore, an increased need to urinate more frequently. Often, these dogs will have a ravenous appetite, but lose weight. Some dogs may have such advanced diabetes that they feel weak, lethargic and may even stop eating. Vomiting, diarrhea, and breath odor may also occur.


The cause of diabetes and reason for the clinical signs of hunger and thirst is due to disease in the pancreas. The pancreas has two major functions. The first is to secrete digestive enzymes into the digestive tract and to help the body process the food eaten. This function is usually not affected by diabetes. The second function of the pancreas is to secrete insulin into the blood stream. Insulin serves as the "key" that allows blood sugar to enter the cells of the body and, therefore, fuel the cells. When a dog eats a meal, the digestive system releases sugars into the blood stream. If there is not enough insulin to allow the sugar to enter the body's cells, the sugar cannot be absorbed and used. The brain's cells feel "starved" and stimulate a sensation of hunger. The dog may eat more, but without insulin, the sugars cannot leave the blood stream. The increased level of sugar in the blood stream also stimulates an increased thirst reaction as the body tries to dilute and "wash out" the excess sugar in the blood stream. The excess sugar is released into urine. In diabetics, the urine can sometimes be so full of excess sugar that it can feel "sticky" when an owner cleans up an accident on the kitchen floor. A likely scenario when these dogs drink so much water that they cannot always wait until they are allowed to go outside to urinate. In time, the starving cells in the organs of the body can cause the organs to stress and fail. If untreated, permanent organ damage, shock, coma, and death can occur. Diagnosis of diabetes mellitus is usually uncomplicated. Blood work will show an elevated blood glucose level and a urinalysis will show an overflow of sugar into the urine. If the diabetes is severe or present for a long time without treatment, organ damage and/or infections may be present. Urinary tract infections are especially common due to the high volume of sugars in the urine that make excellent fuel for bacteria to thrive on. Cataracts are also a common result of diabetes.


Once diabetes has been diagnosed, an insulin dosing plan must be started. Some dogs can be treated with a once a day, long lasting insulin injection. Other dogs need twice a day dosing. Finding the correct dose and required frequency can take time, money, and patience. The dose will be monitored according to changes in the dogs thirst, appetite, blood sugars and sometimes fructosamine levels. Fructosamine is an enzyme measured in the blood that reflects the dog's average blood sugar over the past 2 to 3 weeks. While it doesn't tell us the highs or lows, it can sometimes help veterinarians know when they are getting closer to better regulation. Diet is also an important part of controlling diabetes. Feeding must be consistent and given at times when the insulin can be most effective. Prescription foods are often used.


With careful and patient monitoring, a correct insulin dosing plan can be found and dogs can live healthy lives with good quality of life.


© 2003 Carla Douple, DVM. All rights reserved. For permission to reprint contact author at Landisville Animal Hospital, 3035 Harrisburg Pike, Landisville, PA 17538