Diabetes mellitus in cats is a complex disease that is characterized by the inability to produce or use insulin. The hormone, insulin is released by the pancreas and is responsible for regulating blood glucose. If insulin is absent from the body or the body is not reacting to insulin, the glucose that the cat is putting into the body by eating is not used for energy. To make up for the lack of energy the body needs to function, the feline’s body targets its protein and fat reserves. As a result, the cat will quickly lose weight as more and more of the fat storage is being used. Eventually the protein and fat storage will run out, resulting in a terminal condition that must be addressed by a veterinary professional.

The symptoms associated with diabetes mellitus in cats are the body’s response to evaluated concentrations of blood glucose and the body’s inability to use the available glucose as a source of energy. A cat may respond by showing an overall body weakness paired with weight loss, polyphagia, polyuria, and polydipsia. A diabetic cat will have a decreased ability to fight bacterial and fungal infections, making them susceptible to chronic or recurrent infections. Felines often develop hepatomegaly, or fatty liver disease, as a result of lipid accumulation caused by the weight loss effects of diabetes mellitus. To summarize, felines suffering from diabetes mellitus will display the following clinical signs: 

Diabetes mellitus in cats is divided into two groups; Type 1 and Type 2, with Type 2 diabetes mellitus being the most commonly seen in felines. 

Diabetes mellitus feline cases have greatly increased, as the domesticated life we provide for our pets mimic the human lifestyle. Felines that are fed a high carbohydrate diet, are obese, and live a sedentary lifestyle are at a very high risk for developing diabetes mellitus. Veterinarians also find cats that suffer from chronic renal insufficiency, hyperthyroidism and have been prescribed corticosteroid drugs over a long period of time are prone to developing diabetes. We also tend to see cats of older age, over eight years, and neutered males present pancreatic insufficiencies at a higher rate than other felines. 

The diagnosis of diabetes mellitus in cats is based on the feline’s presenting clinical signs paired with the presence of glucose in the urine and in the blood. However, initial diagnostic tests that reveal glycosuria (glucose in urine) and/or hyperglycemia (glucose in blood) are not clear signs that a cat has diabetes mellitus. In fact, your veterinarian may ask for blood draws on your cat over several weeks’ time to properly diagnose the feline with diabetes. The reason behind this is because stress also causes the feline’s blood and urine to show a presence of glucose. As a cat become frightened (a common occurrence at vet visits) the body reacts by releasing glucose energy into the bloodstream, which would allow the cat enough energy to run away from the frightening situation. Therefore, the vet may choose to perform a urinalysis and blood tests for a few days to make a positive diagnosis. He or she may also choose to perform a fructosamine blood test, as this test in not altered by a cat’s stress level and can indicate the average blood glucose levels over a week’s time. 

The goal of treating diabetes mellitus in cats is to replace the lost insulin levels in the body. Your veterinarian will likely recommend a diet change, recommending cat foods high in protein and low in carbohydrates. As felines diagnosed with diabetes are often overweight, the doctor may also work with you to develop a weight loss plan for your feline. Aside from a veterinary recommended diet plan, your feline will need to place on a lifelong therapeutic treatment to replace the loss of insulin. Treatment options your veterinarian may suggest include: 

An insulin injection is the most common treatment for feline diabetes mellitus, administered twice daily. 

An oral tablet that is given daily to promote insulin secretions from the pancreatic organ.

The majority of cats can experience a long and happy life after being diagnosed with diabetes mellitus, but it depends on the pet owner. You will be required to monitor your cat’s blood glucose levels every day, just like a person with diabetes would do. Periodic checkups are necessary, especially in the beginning stages of treatment, to ensure you are calculating glucose levels accurately. The veterinarian may also alter your cat’s treatment plan over time, so following the doctor’s directions exactly is important.