Dogs and Cats Can Suffer From Diabetes

Dr. Sherman Gilbert, DVM

Sophie is an eight-year-old Labrador. She was presented by her owner because she was “getting old” and he wanted her checked. “Maybe she has arthritis.” As we discussed Sophie’s history, we found that she was not as active as she had been in the past, had lost weight, and drank plenty of water. “She is constantly drinking, it is always wet over on the floor by her dish and I fill it up all of the time.” A physical exam, blood and urine tests were performed and Sophie was diagnosed with Diabetes Mellitus.

Many people are aware of Diabetes Mellitus in humans, but are surprised to find out that it occurs in dogs and cats also. It may be even more surprising for people to find out that there are animals with type 1 as well as type 2 diabetes. Type 1 diabetes is also called insulin-dependent. The body does not secrete enough insulin and this can be corrected with supplementation of insulin. This type is found in dogs. Type 2 or non-insulin dependent, is mostly found in cats. Insulin secretion in this type exists from normal to low levels, but the cells of the body are resistant to the insulin and so sugar (glucose) becomes high in the blood. By the time many cats have been presented to the veterinarian they have become insulin dependent. Obesity is a risk factor for this type in cats as it is in humans.

Blood glucose levels rise in the blood because it is not being used by the cells and because there is an increased production of glucose by the body as the cells are calling for energy (glucose) that they can’t get. The body tries to dilute the high amount of glucose molecules in the blood by allowing more water to enter the blood (osmotic diuresis). This makes the animal urinate more as the water and glucose are eliminated by the kidneys. In turn the animal will drink more water to compensate. Over time the animal will become dehydrated. As the body is not able to use glucose for energy, the animal will lose weight while usually eating more. As the diabetic state progresses, fat will be used for energy. Lactic acid and ketones are produced as break down products of fat. Elevated levels of lactic acid and ketones along with loss of electrolytes in the urine and water will cause dehydration, low blood volume, shock and metabolic acidosis (more acid pH of blood). Owners will see their pet become lethargic, not eat and vomit. Pets become more and more dehydrated and not as much blood passes through the kidneys to be “cleaned” and ketones and glucose levels will further increase in the blood, making them worse and worse. Owners may also find their dog has suddenly developed cateracts and can’t see. Cat owners may notice gait abnormalities (usually low hocks), or chronic not eating, diarrhea or vomiting.

Pets that are presented very sick with a urine test showing ketones, not eating and vomiting, need to be hospitalized. Intravenous fluids are used to help correct the shock, dehydration and the metabolic acidosis. Regular insulin given every hour or continuously in the IV is used to lower blood sugar. Many pets can be treated and recover to be sent home and managed there.

Pets that recover from ketoacidotic diabetes, or pets that never get that sick, are treated at home. For dogs with type 1 and many cats, treatment involves a change in diet and insulin injections, along with patience and dedication. Pets may be fed different diets to either help them lose weight, maintain or gain. Dogs are typically placed on a higher fiber diet. This helps slow the glucose absorption from the GI tract, reducing a large surge just after a meal. Cats may be placed on a higher protein diet for treatment, similar to the “Atkins diet.” Pets are usually given injections of insulin once or twice a day after eating. Owners are taught how to do this at home. They also may monitor the urine for glucose or ketones and measure how much water the pet drinks. Blood tests are done to determine how well controlled the animal is and to see if the insulin dose needs to be adjusted. Blood testing is more frequent at first as the right amount of insulin is found, but after that it may only need to be done every six months and if the owner notices changes in how much the pet drinks and urinates or changes on the home urine tests. Some cats with type 2 may be treated with oral medications and diet change alone, however many will need injections of insulin. Diabetes can be treated, and with dedication, animals can live long healthy lives with the disease controlled. (Doctor Gilbert is a veterinarian with Emery Animal Health.)