Diabetes mellitus (sugar diabetes)
Diabetes mellitus is a condition that affects both dogs and cats and is caused by either a lack of production of insulin or by insulin resistance. Insulin is a hormone secreted by the pancreas that allows the body to absorb sugar into the cells for energy production. It is also involved in protein and fat regulation as well as that of potassium and magnesium.
When your pet can’t produce sufficient levels of insulin or there is a relative resistance to insulin, normal pathways of metabolism are unable to function. Sugar can’t be absorbed into the cells resulting in cellular depletion of energy and high levels of sugar in the blood (hyperglycaemia). Proteins and fats become the predominant energy source, resulting in a build-up of dangerous keto-acids. Potassium levels increase as insulin is required for cellular uptake.
Diagnosing diabetes can be a little tricky – patients can be presented as either normal or unwell. There is usually a history of increased thirst and weight loss although as it is gradual sometimes the owners have not noticed the changes until the animal is put on the scales and the weight is compared to previous visits.
The increased thirst is caused by the increase sugar in the urine dragging excess water with it as well as the blood metabolic derangements. With the body unable to absorb sugar into the cells, protein stores and muscle are broken down, resulting in weight loss. Keto-acid build-up from abnormal fat breakdown can result in an acid (low pH) state in the blood, resulting in panting, vomiting and lethargy. Patients are often dehydrated. If the patient has become ketotic, i.e. they have critical acid build-up in the blood, they may be very unwell.
Diagnosing diabetes
Diabetes is not a condition that can be left untreated as the changed in metabolism will eventually become life threatening.
Diagnosis is based on a thorough history, examination and blood tests. The patient often has dry gums or skin tenting suggestive of dehydration. They may be lethargic and panting due to acidosis. The liver may feel enlarged. Temperature is often normal. The heart and lungs generally sound clear. There may be an odour to the breath suggestive of ketones. Urinary infections and cystitis are often noted due to the presence of sugar in the urine. In severe long-standing untreated disease in cats we may see an altered gait and 'dropping' to the hocks.
Laboratory tests will indicate hyperglycaemia that is generally higher than twice normal levels. There may be ketones in the blood and urine and the bloods may be more acidic. Liver enzymes may be elevated. There will be sugar and possibly secondary infections in the urine.
Treating for diabetes
Treatment initially varies depended on how unwell your pet is when they are presented. If your cat or dog is well, we can usually start insulin therapy immediately to regulate metabolism. If your pet is unwell, dehydrated or has secondary infections, we may need to rehydrate first with intravenous fluids.
We start insulin at a standard dose rate then take glucose tests through the day to make sure we are achieving the desired levels. We will also make dietary changes to reduce the carbohydrate component of the diet and to increase the relative amount of protein.
Once stable and on acceptable levels of insulin, the patient is usually discharged from hospital. You will have a discharge appointment with our vets to teach you how to give insulin via injection. Most people are nervous the first couple of times they inject their pet but then they find it easy. You will usually be asked to come back in for a recheck in one to two weeks so we can check the blood glucose levels to make sure your pet is still in the right range. Based on these results we may reduce or increase the amount of insulin being given. You should never make any changes to the insulin levels yourself without contacting our vets first.
We shall also work out a diet with you that best suits your pet. The timing and amount of food will be discussed. You should not randomly feed a diabetic animal as it makes insulin regulation difficult.
With insulin therapy and dietary changes many cats can recover from diabetes and may not need insulin for the rest of their lives. Others do and there is no way to predict which ones will need insulin and which ones won't. Dogs usually do not resolve the problem and in most cases are diabetic for life.
Reduce the chance of diabetes
You can reduce your pet’s chances of developing diabetes by good weight management and adequate protein diet. Cats are carnivores and as such have a greater requirement of protein than dogs. We recommend 50% of your cat's diet is wet food, ie. tinned or fresh/cooked meat. The other 50% a good quality dry food. If you have one of those cats that will only eat dry food, then talk to one of our vets and they can recommend a prescrition diet such a Hill’s MD or Royal Canin diabetic, which have lower carbohydrate and higher protein levels. There are also specific diets manufactured for dogs with diabetes mellitus.
Ongoing weight monitoring is important. Just like with people, obesity can be a precursor to diabetes. Fat can be insulin resistant, leading the pancreas to produce excess insulin and exhaust supplies. Other hormonal diseases such as hyperadrenocorticism, acromegaly and hyperthyroidism can also predispose the animal to the disease. Certain drugs such as corticosteroids, Ovarid and other progresterones have also been implicated as causative factors. There are some Burmese lines that also appear to be more predisposed to diabetes.
Diabetes is a challenging condition but with commitment it can be well managed and we have many diabetic pets who live long and happy lives.