Macarthur Veterinary Group
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What is Diabetes?

Diabetes mellitus is a disease where the body is unable to properly regulate blood sugar, because of a deficiency of a hormone called insulin. Download PDF Download a PDF of this Article

What are the symptoms?

There are four classic symptoms of diabetes:

  • Increased thirst
  • Increased appetite
  • Increased urination
  • Weight loss

There are other diseases that will produce these signs – but together they are very suggestive of diabetes. However, you may not always see all four symptoms. The appetite may be reduced by other illnesses or complications of the diabetes. And you may not notice how much your pet is drinking or urinating (especially in cats). If you see any of these symptoms, you should have your pet examined by one of our vets. Diabetes will make your pet very sick and eventually can be fatal.

Are there any long-term side-effects?

Yes, unfortunately there are many other serious side-effects of undiagnosed or poorly-managed diabetes. Excess glucose in the bloodstream will cause damage to nerves, small blood vessels and a number of vital organs.

Diabetes can lead to blindness (from cataracts or retinopathy), kidney failure and nerve damage. It also increases the risk of developing many other diseases such as bladder infections and adrenal disease.

Which animals are more likely to get diabetes?

Diabetes is more common in dogs than cats. It occurs in middle to old-age dogs, more often in females. Some breeds are more commonly affected than others, including miniature poodles and schnauzers.

Diabetes is an uncommon disease in cats, but is seen more frequently in middle to old-age cats and more common in males than females. Burmese cats are more commonly affected than other breeds.

Overweight animals are also much more likely to develop diabetes.

In some cases, particularly in cats, diabetes may occur secondary to other factors such as obesity, pancreatitis or drug administration. Removing these predisposing causes may eliminate the signs of diabetes. Unfortunately though, most pets will have diabetes for the rest of their life.

How is diabetes diagnosed?

The diagnosis of diabetes is based on 3 criteria:

  1. The four classic symptoms (see above)
  2. Persistently high blood Glucose
  3. Glucose in the urine

Normally, the level of glucose in the blood is closely controlled in the range of 4 – 8 mmol/L. It may rise to 10mmol/L following a large meal. But with diabetes, blood glucose may rise over 20 or even 30mmol/L.

In many dogs, a single urine and blood test (which we can perform immediately here at the clinic), along with supporting symptoms, may be enough to make the diagnosis of diabetes. However, we will always want to recheck this and confirm that the blood glucose is persistently elevated. In cats, things can be more difficult, as blood glucose levels can rise simply in response to stress. If there is any doubt, a laboratory test (blood fructosamine) can be ordered, which gives an idea of the average blood glucose level over the previous 2-3 weeks. This can help us to differentiate true diabetes from stress associated with another illness.

At the time of diagnosis, your pet will need a complete physical examination, full blood count, biochemistry profile and urine tests. Even if we have made the diagnosis using simple in-clinic tests, the other tests are still important. Diabetes has many potential complications and may be associated with other diseases. These also need to be identified and treated if the diabetes is to be managed successfully.


Diabetes cannot usually be cured, but it can be very successfully managed. Treating a diabetic pet need not be too difficult, and can be rewarding. It does however demand considerable commitment from the owner.

Treatment for dogs (and most cats) requires twice daily injections of insulin for the rest of your pet’s life. Many pet owners initially think that they could never do this - yet most people learn quite quickly. The needles are tiny and relatively painless. Please don’t decide against treating your diabetic pet simply because you are scared to give injections - you will be pleasantly surprised how easy this is.