It is similar to Type 2 diabetes in humans. Problems in the pancreas and insulin resistance both play a role in the development of high levels of glucose (sugar) in a cat’s blood. As with people, obesity is often a major contributing factor. If left uncontrolled, the condition will cause serious health problems.
Symptoms of diabetes in cats are much the same as those in people. Since the body can’t use glucose for energy, the cat is hungry all the time and may appear tired or weak. It may also pass high volumes of urine, as excess glucose in the blood is passing into the urine and pulling water along with it. The cat becomes dehydrated quickly and drinks large amounts of water to make up for lost fluid.
Early symptoms include increased appetite, spending more time at the water dish or drinking water from unusual places such as the bathtub, toilet or sink. The litter box will either seem drenched or urine clumps will be larger and more numerous. Some cats begin passing urine outside of the box. Overall, they look less healthy and often have poor hair coats.
Left untreated, serious problems can emerge along with the progression of diabetes, including irritation of the liver, diarrhea and declining nerve function in the limbs. At this point weight loss becomes much more dramatic. The cat is not only unable to use glucose for energy, but feels nauseous and is unable to drink enough water or eat enough food to get nutrition. Diarrhea means even more fluid loss, and dehydration can become quite severe. With lack of nutrition, the cat becomes weak. Since nerve function is dramatically affected, skeletal muscles don’t work well either.
The cat gradually eats less, so more food is left over in the bowl. It may get a lot fussier about what it will or won’t eat. At first the cat may appear hungry and come running when it hears you filling the dish. However, once there it will take a sniff and just walk away or begin drooling or ‘lip-smacking.’ These are all symptoms of nausea in a cat.
The cat’s weight loss may not look as you might expect. When people lose weight, fat stores are used fairly quickly so we begin to appear slimmer. Our bodies avoid breaking down our own muscle tissue as a protein source (a process called muscle wasting) until very little fat is left. However, a cat can lose a lot of weight and still look quite obese. As carnivores, the cat’s body has adapted to eating large amounts of protein in the diet. During starvation, the body breaks down muscle protein very quickly. Although the cat may still look obese (because it is), if you feel through the layers of fat you will find that the muscles are weak and wasted.
Lameness, another major symptom of advanced diabetes, emerges as a result of the combination of weak muscles and poor nerve function (called diabetic neuropathy). Along with seeming more tired, a diabetic cat first becomes very weak, especially in the hindquarters. Eventually it becomes wobbly or unable to walk. It may appear stiff and in pain. Many cat owners notice their pet has difficulty jumping or climbing stairs. Over time, cats may develop a condition often referred to as dropped hock syndrome. The cat stands with the hocks (the major joint above the paws) touching the floor.
As with our own health, early diagnosis is very important for successful management of any long-term illness. The tough part is that our animals can’t tell us what is wrong. As a result, most diseases have progressed considerably before symptoms are noticed. Annual checkups are an essential part of your pet’s health care. The checkup should include a thorough physical exam, a complete medical history and, depending on the cat’s age and present health, routine blood testing.
Cats can hide illness very well, so even small changes in their behavior often provide significant clues that should not be ignored. In my experience, people who spend a lot of time interacting with their cats have a sense that something just isn’t right. If you think your cat is acting unusual or showing changes in behavior, see your veterinarian. You may help stop a serious health problem from progressing further.
Getting started. The amount of information available about diabetes in cats can be overwhelming. Work closely with your veterinarian, be consistent, ask lots of questions, and stick with what works well for your cat. For both cats and people, the two main types of medication available are insulin and oral medicines that lower blood glucose. In cats, oral medications tend to help only in very early or mild cases and are of limited use due to the risk of severe side effects. Insulin injections and diet make up the mainstay of therapy.
Consistency is crucial. Most cats do best when fed twice daily (every 12 hours), just before their insulin injection. A small snack should be given midday when the blood glucose is lowest. Try to co-ordinate this with your own schedule to establish a good long-term routine.
Use canned foods low in carbohydrates and high in protein. Some prescription diets are specially formulated for diabetes, while in some cases kitten diets may be used. The right food can help lower blood sugar, make insulin more efficient and let the cat feel fuller while eating less. Increased (insoluble) fibre in the diet also helps. Some cats can be managed on diet alone.
Insulin Therapy. Once a diet plan is in place, the diabetes can be stabilized with insulin therapy. Many different types of insulin are available. Many diabetic cats respond well to long-acting human insulin, such as lente or ultralente, administered every 12 hours with a meal. Though injecting your cat seems risky, most tolerate it surprisingly well. The cat may not even notice an injection given through the skin over the shoulder region while it is busy eating. Your vet can make sure you are comfortable with injection technique and proper handling and storage of insulin. Your pharmacist can also answer questions about insulin injection and teach you the right way to dispose of insulin syringes.
Monitoring Progress. Your vet or animal health technologist will review the best way to monitor your cat. You will be taught how to recognize and treat a low blood sugar reaction, sometimes called ‘insulin shock’. A simple log on a calendar can keep track of trends. Expect common symptoms of diabetes such as changes in appetite and weight, increased thirst and urination to improve with treatment. Overall signs of health such as improved coat quality, resuming normal behavior and activity level should also be observed.
In a few cases, testing urine and blood glucose levels at home might be helpful. Since test results can fluctuate drastically, results may be of limited use. The most useful overall test monitors the fructosamine level in blood sugar. It is done in-clinic and tells how well managed the diabetes has been over the last 2 to 3 weeks. In a well-regulated cat with diabetes this test should be done at least twice a year.
While diabetes can be challenging to manage, many cats and their owners do very well. Find the best individual treatment plan and be consistent with treatment and feeding schedules. Set up regular visits to the vet to monitor your cat’s health. With proper treatment, many diabetic cats live full lives for years.