by Christopher Forsythe, DVM

Hello, readers. Welcome to Health Matters. My name is Dr. Christopher Forsythe. I am a small-animal veterinarian practicing in Sonoma. Each month I will contribute a pet veterinary care topic with the hope of tweaking your interest, making you smile, and educating you about your pets.

Sometimes my friends laugh in disbelief when I tell them I’m treating a diabetic patient at my hospital. "Do dogs get diabetes too?" they ask, incredulous. Small animals get most of the nifty diseases we get, including diabetes, and they need and deserve the care we get for ourselves. Many devoted pet owners diligently give their beloved pet insulin injections.

About one out of 400 dogs and cats develops diabetes, which means they have an insulin deficiency and thus a decreased ability to use glucose, fats, and proteins that the body needs. Many pets do well for years after being diagnosed, while others cannot be regulated and either die or need to be euthanized soon after diagnosis.

Why are you drinking me out of house and home?

The classic clinical signs of diabetes include increased drinking (pets lap up water like a thirsty drunk at a beer bust), urinating, eating, and weight loss. Other signs include depression, anorexia, and vomiting.

Dog owners sometimes notice cloudiness in the eyes due to developing cataracts. Urinary tract infections are common in diabetic pets. Many owners report pets frequently urinating with the urine smelling quite strange. The pungent smells of rotten pineapple or sour grapes make some owners wonder if their pets are urinating wine rather than pee. What should any or all of these signs tell you? Bring your pet in for a check-up.

Luckily, the diagnosis for diabetes is usually pretty straightforward. In dogs, the presence of elevated blood glucose and urine glucose is enough. Cats are a little more challenging, as usual. Cats under stress can experience blood and urine glucose levels that shoot up quickly. If a healthy cat, for example, squirms around while having blood drawn, his sample would very likely show a markedly elevated blood glucose. Thus, it is very important to consider clinical signs to definitively diagnose diabetes.

Insulin’s role

Type I diabetes is the most common form recognized in dogs. This type is thought to be due to destruction of the beta cells in the pancreas. This loss can be from pancreatitis, infection, or other causes. The destruction of beta cells leads to the loss of insulin secretion.

Type II diabetes is characterized by insulin resistance or dysfunctional beta cells. In this type of diabetes, insulin secretion by the pet can be high, low, or normal, but it is insufficient to overcome insulin resistance in peripheral tissues. Both Type I and Type II diabetes are seen in dogs and cats. Insulin tells the cells of the body to take sugar out of the blood stream and use it for energy. It also facilitates the uptake of proteins and fats into tissues, and stimulates glycogen synthesis (useable energy) stores in the liver.

Deficient insulin leads to increased glucose production and decreased glucose utilization, which results in high blood glucose. The kidneys lose their ability to resorb the sugar, resulting in elevated urine sugar levels. High urine sugar levels combined with the pet’s inability to use his glucose efficiently lead to weight loss and stimulation of the satiety center in the brain. This explains why many diabetics feel "full" all the time.

Dealing with diabetes

Many pet owners are dumbfounded when they learn their pet has diabetes. They have to overcome the shock, understand the severity, and become educated about associated ramifications. They must learn what caring for a diabetic pet will be like. Some key points they must remember:

• Type I diabetes is a lifelong disease usually requiring insulin injections twice a day. Type II may or may not require insulin injections. Most dogs with diabetes are insulin dependent where some cats may have transient or intermittent Type II diabetes.
• Diabetics require significant veterinary monitoring and testing to stay healthy. This includes more frequent physicals, blood glucose testing, CBC chemistry, blood fructosamine testing, urinalysis, and urine cultures.
• Ketoacidosis is a life threatening complication of Type I diabetes and is caused by the metabolic breakdown of fats. If a pet becomes ketoacidotic, you will notice a particularly bad "medicine breath." Hospitalization becomes necessary and prognosis becomes guarded.
• Blood glucose levels and insulin needs can change as your pet’s health or age does. Many factors, such as thyroid disease, cancer, heart disease, allergies, obesity and more can affect the status of diabetes in a pet.
• Diabetes is a serious disease that requires careful dosing, close monitoring, and excellent medical oversight. Therefore, it is imperative that you and your veterinarian have an excellent rapport and are comfortable with discussing the needs of your pet. Your pet will have the best possible prognosis if you are an educated and empowered pet owner, you follow your veterinarian’s advice, and you choose a veterinarian with a high standard of medical care.

Insulin innovations

In the past, most commercial insulin products were chemical extracts of a combination of bovine and porcine pancreas. Today, genetically-engineered insulin products are available, enabling us to regulate dogs and cats more smoothly and with fewer complications. Among these are PZI, Vetsulin, Lantis, and Humulin insulins.

The aim of insulin therapy is to maintain the normal range (80-180mg/dl) of blood glucose concentration for as much of a 24-hour period as possible. At the least, our goal is to control the blood glucose level so that clinical signs of diabetes resolve. We want the dog to get back to his obedient self and the cat to return to his superior self, as soon as possible. Make sure you understand the safe storage and use of insulin.

You are what you eat

Recent studies support the feeding of a complex carbohydrate, high-fiber food to diabetic pets. The diet you choose should prevent weight loss in thin pets and control obesity in heavy pets. Pets should eat every 12 hours, at the time they receive an insulin injection.

Diabetic crisis

By far the scariest thing in the world for owners is a hypoglycemic crisis which can occur if your pet is accidentally overdosed with insulin. Your pet may act like Paris Hilton after a night on the town: groggy, listless, sleepy, can’t raise her head, won’t respond, and can even seizure. Life saving measures must be taken by your veterinarian immediately. Until you can get to the hospital for emergency medical care, your vet will likely recommend corn syrup or honey syringe-fed into her mouth to raise her blood sugar level from a precipitously low level.

Education is an important component of patient management. You should learn to handle and administer insulin and keep a diary of your pet’s progress. You must ensure a regular routine for him. You should know how to monitor urine glucose and ketone concentrations using commercially available urine dip-sticks. You should contact your veterinarian if changes occur, particularly if ketones are detected.

You should not use such measurements to adjust the insulin dose, since life-threatening over-dosage can occur if decisions about glycemic control are made based solely on urine glucose measurements.

Most important is that you maintain a close relationship with your pet and your veterinarian as you meander the diabetic pathway. This disease is treatable, but requires patience, effort, and investment in time and money to keep your pet well and happy.