Cassie the retriever was diagnosed with diabetes mellitus last year, and has twice-daily treatment with insulin. Apart from her injections, and regular blood tests, she is able to lead a normal life and do all the things she enjoyed before she became diabetic. Cassie is just 6 years old, but with good management of her condition, she has every chance of enjoying a full life.
Diabetes is an illness where the animal has a lack of the hormone insulin, or the body does not respond normally to its own insulin. Insulin is produced in the pancreas, a gland which lies close to the stomach. Usually, insulin helps keep the level of glucose in the bloodstream stable. When glucose levels start to rise, insulin is produced to halt this rise in a number of different ways: it increases the uptake of glucose into body tissues, it stimulates conversion of glucose into glycogen for storage in the liver, and it stops glucose production from metabolising fat and protein. Without insulin, glucose levels in the blood go on rising (hyperglycaemia), causing a variety of symptoms. When it reaches a certain level in the blood, the kidneys can no longer filter it out so glucose appears in the urine (glycosuria). This creates ideal conditions for bacteria to live and multiply, so urine infections can result.
The symptoms of diabetes in dogs or cats include drinking more than usual, urinating more than usual, eating more than usual and weight loss despite a good appetite. If left untreated, complications like liver disease, cataracts and weakness develop, and ultimately it can be fatal. In most cases, the first thing noticed by the owner is an increase in thirst. Obesity can be a factor in causing diabetes and is a very important reason to keep your pet at a healthy weight.
Diagnosis is made by a full clinical examination and by urine and blood tests. Diabetes is not the only condition which causes these symptoms, and it can occur in combination with other conditions, so it is important to get a definite diagnosis and to rule out other illnesses. Stress can cause a temporary rise in blood glucose, so it may be necessary to repeat the tests before the diagnosis is made. When a high level of glucose is found in the blood, a second test may be done to check the levels of fructosamine. This tells us whether the blood glucose has been raised over a period of several weeks, or if it has just happened. Further tests may be needed to confirm that diabetes is present and to rule out other illnesses.
Treatment of diabetes is nearly always by injections of insulin, given once or, more commonly, twice daily. These need to be given for the rest of the animal’s life, except in a few cases where the diabetes goes into remission and treatment can be stopped. This happens more often in cats than in dogs. These cases will be picked up by the monitoring carried out by your vet.
Giving injections to your own dog or cat can seem quite daunting but is actually much easier than most people think. The needles used are very small so that the injections do not hurt, and full training will be given by your vet or vet nurse. The insulin has to be kept under the right conditions (upright, in the fridge) and must not be shaken, but these things very quickly become second nature. Noting any changes in your pet’s thirst, appetite and urination can also be useful.
At the start of treatment, your dog or cat will need to be stabilised on the right dose of insulin, which differs with each patient, by slowly increasing until the right dose is reached. Your vet may also carry out a test called a glucose curve, when your dog or cat is blood tested at frequent intervals over a 24 hour period. This helps by showing how long after an insulin injection the glucose levels dip to their lowest level, and how long after eating the blood glucose levels rise to their maximum level. The aim is to control the glucose level throughout the day as close to normal as possible.
While your dog or cat is undergoing tests and being stabilised, it might be hospitalised, but usually treatment can be given at home after a short time. Regular blood tests every few weeks (or months if very stable) will be needed after that. Sometimes owners will perform some of these blood tests at home using a kit very similar to that used by people with diabetes to test their glucose levels. The use of glucose testing kits which give a very rapid result, whether used at home or at the surgery, means that it is no longer necessary to collect daily urine samples from the pet. Monitoring the glucose in the blood can be more accurate and allows better control of the insulin dosage.
A diabetic dog or cat needs to have a regular amount of exercise and food, given as near as possible to the same time of day each day. A special diet may be recommended by your vet because it helps to control the condition if the diet is higher in protein, lower in fat, higher in fibre and contains carbohydrates which release their energy slowly. All of these help to keep glucose levels as stable as possible, with no sudden peaks or troughs. Keeping your pet at the correct weight is also important.
Unspayed bitches which develop diabetes may suffer from changes in their insulin requirements when they come into season, because of other hormonal changes, which may destabilise them again. Your vet may want to discuss neutering with you.
Complications can occur in diabetes and your vet or nurse will make you aware of what problems to look out for. The most likely would be if glucose levels fell too low (hypoglycaemia). The dog or cat would become confused and twitchy or may collapse. It is essential to have some form of sugar or honey easily available to give by mouth if this happens, and then to phone the surgery straight away for further advice.
Looking after a dog or cat with diabetes requires a certain amount of commitment from the owner, but most people say that it becomes easy once they get used to it. The key is to give your pet a standard daily routine of food, exercise and insulin injections, and to use your veterinary surgery for support and advice whenever you need it. Most diabetic dogs and cats will have a very happy life without even being aware that they have a medical condition.
If you are worried that your dog or cat may be displaying symptoms of diabetes please call your vet immediately. If you are not sure how urgent the situation is please use our interactive pet symptom checker
Jenny Sheriff BVM&S MRCVS