Pet Illnesses

Diabetes: Introduction

Diabetes is a relatively common condition in cats and dogs and is on the increase, just like in humans. Most commonly it is due to a lack of insulin production by the pancreas, but sometimes it is due to other diseases or conditions interfering with the action of insulin.

Types and Causes of Diabetes

Type 1 Diabetes

Type 2 Diabetes

Pancreas normalPancreas inflammed

What is Diabetes?

During digestion, a pet's food is broken down into components that can be used by its body. Carbohydrates (starches), for example, are converted into various sugars- of which glucose is the most important. Glucose is absorbed from the intestines into the blood and provides the body cells with energy.

Glucose, however, can only penetrate most cells in the presence of a hormone called insulin. If there is a shortage of insulin, too much glucose stays in the blood and the condition known as diabetes mellitus develops. Basically diabetes is a shortage of insulin.

In some cases, however, diabetes arises from a relative insulin shortage that is brought about by overproduction of other hormones which interfere with the action of insulin e.g. cortisone in Cushing's disease.


Pets with diabetes can display many signs, the most common being:


A vet will have some alarm bells ringing when taking a good history from the pet owner and doing a thorough clinical examination.

The symptoms may certainly indicate diabetes, but they are also seen in other diseases. The diagnosis only becomes definite when glucose is found in the urine in combination with high glucose levels in the blood.

The presence of glucose and especially ketones in the urine level gives stronger evidence that the animal is suffering from diabetes than the mere presence of elevated blood glucose levels. Cats and easily stressed dogs are notorious at having artificially elevated blood glucose levels with just the minimal amount of stress e.g. a short car ride. They will have normal urine samples so can be quickly ruled out.


Insulin is a hormone that keeps a pet's glucose concentration at a normal level. It is produced by certain cells in a gland called the pancreas. In diabetic animals, these cells do not produce enough insulin and sometimes none at all. This disorder is most common in older bitches and castrated male cats, but it is also seen in young animals of both sexes. In some breeds there is an above average incidence of diabetes.


Glucose Curves

A vet will start a newly diagnosed diabetic patient on a course of insulin injections. After a couple of days of therapy, bloods are collected every 2 hours following a morning dose of insulin, to measure the blood sugar levels.

Depending on how the blood glucose curve looks, adjustments are made to the dose.

Once the patient is stabilised, the vet will want to perform glucose curves on a regular basis to make sure all is well. This is very important in cats as quite a few actually start to make their own insulin once therapy starts. In these cats, it is easy to get an overdose if the dose of insulin is not lowered or stopped all together.

Insulin Overdosage

See also...

Owners Commitment

Fortunately, diabetes can be dealt with very successfully - but treatment requires a great deal of care and day to day consistency on the owners part. Owners must be fully committed. Treatment can not be entered into half-heartedly.

Diabetes is expensive to treat, and requires a lot of blood tests and regular check ups by the vet.

Owners have to inject their pet once or twice a day which their vet will show them how to do. It is not as hard as it sounds. There has to be a set routine in the household for timing of the insulin injections and some system where a box is ticked when it is done so there can be no chance of an accidental double dose being given.

The vet will give the owners a run down on diets and the importance of avoiding scraps and treats in between injections. Full compliance with the vet's instructions is vital for successful treatment.

If all this seems too hard, then euthanasia is the best option.