Diabetes mellitus

Diabetes mellitus is a dysfunction of the pancreas. The pancreas is an endocrine organ that possesses clusters of cells known as islets of Langerhans. These secrete insulin into the blood circulatory system in order to control the glucose level in the blood, and stimulate absorption of glucose into cells. Diabetes mellitus is an entirely different condition to diabetes insipidus, which this article does not focus on.

Diabetes mellitus is thought to be extremely rare in pet rabbits, although it is relatively common in cats, dogs and humans. It is mentioned in rabbit textbooks but the vast majority of vets have never seen a true case in a rabbit.

The most commonly seen symptoms that may indicate diabetes mellitus include:

  • Excessive thirst
  • Excessive urination
  • Excessive eating
  • Lethargy

These symptoms can appear suddenly or have a slow onset and vary in severity from animal to animal. It is also important to remember that these symptoms can be attributed to many other disease processes that are more likely to affect rabbits, so although diabetes mellitus is always on the differential list of possible causes, it does not normally feature near the top of the list.

It is relatively easy to diagnose diabetes mellitus; a simple drop of blood on a glucometer (a device for determining the approximate concentration of glucose in the blood) showing a high blood glucose may indicated diabetes mellitus.

However, when rabbits are stressed their blood glucose can rise dramatically and blood glucose levels in rabbits are often used, in conjunction with clinical signs in anorexic rabbits to distinguish between rabbits with GI stasis and those with true blockages who require surgical treatment.

Therefore, a high blood glucose in a rabbit needs interpreting with care and alongside clinical signs.

Rabbits that indicate clinical signs and have high blood glucose levels may be suffering with diabetes mellitus. A further blood test can be undertaken (fructosamine), which measures the blood glucose levels over a couple of weeks, which gives a much better indication of diabetes mellitus than a snapshot which is what a spot test blood glucose level gives.

Urine analysis to look for glucose in the urine is also advised alongside blood analysis. This is performed quickly and easily on a dipstick test.

If diabetes mellitus goes untreated then the rabbit may become hypoglycemic, whereby there is not enough glucose in the blood. This is extremely dangerous and can be fatal. Symptoms include tremors, twitching, collapse, unconsciousness and death.

Obese rabbits are thought to be at a much greater risk of developing diabetes, which is another reason why a good diet plays a vital role in keeping your rabbit fit and healthy.

The treatment of choice with rabbits who do have true diabetes mellitus is often a healthy diet. Most rabbits that have been diagnosed with diabetes mellitus have been overweight, which has been a trigger factor. Encouraging a healthy diet can reverse the process or at least control it.

All rabbits, including those with diabetes mellitus, should be fed a diet of the following:

  • Unlimited, good quality hay – this should make up 80% of the diet.
  • Fresh vegetables – this should make up 15% of the diet.
  • A small amount of good quality pellets – approximately 1 egg cup full per rabbit per day making up no more than 5% of the diet.
  • No junk food or treats should be given as these are often rich in carbohydrates.

Insulin injections are not generally needed in a rabbit with diabetes mellitus, since they do not metabolise insulin like cats, dogs and humans, but you should be guided by your vet. Those rabbits that are obese or overweight should naturally start losing weight, at a slow rate, on a healthier diet.

If clinical signs are evident then these need appropriate management. Rabbits with excessive thirst and urination need their litter tray and environment cleaning more frequently. Those with an excessive appetite can be offered extra hay and grass, but this should be available ad lib regardless.

So few rabbits have been diagnosed with diabetes mellitus, that it is impossible to give a long-term prognosis.

However, rabbits that are fed a healthy diet, regardless if they have diabetes mellitus, stand the best chance of a long and healthy life.