The result of inadequate insulin production by the pancreas, canine diabetes mellitus (DM) is a relatively common disease. Beta islet cells in the pancreas which are responsible for the production of insulin are destroyed over time. There are probably many reasons for beta islet cell destruction including pancreatitis, Cushing’s Disease, acromegaly, infections, intestinal irritation and certain medications. While some dogs are genetically predisposed to the disease, there is no breed predilection.
The disease causes an increase in blood glucose that would normally be distributed to the various tissues for energy in cell metabolism. As glucose levels increase, cells turn to other chemicals for energy. Fat and muscle are broken down in an attempt to satisfy the body’s energy needs. Increases in blood glucose will also overwhelm the kidneys’ ability to conserve glucose and urine glucose levels will rise (glucosuria).
Symptoms of diabetes mellitus include: increased appetite (polyphagia), increased urination (polyuria), increased thirst (polydypsia), cataracts and blindness. These signs may be concurrent with weight loss or noticeable muscle degeneration. Left untreated, blood levels of ketones (the breakdown product of protein metabolism) will increase, causing ketoacidosis and potentially vomiting, weakness, depression, coma or death.
Diabetes mellitus is diagnosed based on a combination of physical examination, a urinalysis and blood work. Because diabetes may be caused by a separate underlying disease, your veterinarian will want to perform the appropriate diagnostics in the hopes of identifying the problem. DM is a relatively easy diagnosis. However, it is very important to insure there are no other abnormalities that may be causing the diabetes or may make control difficult.
Treatment of diabetes mellitus depends on the severity of the disease at the time of diagnosis. Some dogs may require hospitalization for a few days. If the disease is caught in the early stages, however, the pet may be treated at home. Most treatment protocols include a strict diet change and glucose-lowering agents. Diet management involves minimizing large changes in blood glucose levels by controlling the dog’s weight and the composition of the diet. Diets containing complex carbohydrates and fiber are best. Dividing meals into two feedings can also help control glucose fluctuations. Common diets recommended by veterinarians include Hill’s Prescription Diet W/D, Purina Fit and Trim and Gaines Cycle 3 Light.
Insulin therapy is the drug of choice for the diabetic dog. Most owners are initially apprehensive about administering injections at home. However, with patience and a lesson from your veterinarian, learning how to administer insulin is straightforward. There are different types of insulin which have different durations of effect, including: regular (short acting), NPH and Lente (intermediate acting) and PZI and Ultralente (long acting). Your veterinarian can determine the best type for your dog.
Managing a diabetic dog over the long-term includes occasional trips back to the veterinarian for blood glucose checks, annual physical exams and blood work to ensure no complications. At home, owners should routinely monitor appetite, water intake and urination for changes which may indicate glucose fluctuations. Your veterinarian may also show you how to monitor glucose levels in the blood and urine using test strips. Some pets do not respond to insulin therapy or may develop a resistance to it. In these dogs, a combination of medications may be prescribed. Other dogs may respond very dramatically to a dose of insulin and become hypoglycemic (showing lethargy and collapse).
If you suspect that your dog is hypoglycemic, rubbing some corn syrup on your dog’s gums may help. However, you should contact your veterinarian immediately. Diabetes mellitus is a life-long disease that requires a strong commitment from the owner beyond normal pet care. This essential commitment is an ongoing process of monitoring multiple parameters, controlling diet, administering daily insulin and a long-term relationship with a veterinarian.