Diabetes Mellitus in Cats

Diabetes mellitus is not the same as diabetes insipidus, another hormone condition that has a different cause, diagnostic plan, and treatment.

The major function of insulin is stimulating cells to absorb glucose (sugar) from the blood, in order to produce energy and to carry out normal cell functions. In feline diabetes, the cells are insulin-resistant, meaning they do not absorb glucose when stimulated by insulin. This mechanism for diabetes in cats is similar to Type II diabetes in humans.

Approximately 1% of cats develop diabetes, with overweight cats being strongly overrepresented. Although diabetes is usually a lifelong condition, cats with diabetes have a good prognosis with appropriate management. Many cats enter periods of diabetic remission, where they do not require routine treatment.

Cats showing symptoms of diabetes such as increased urination, increased drinking, and weight loss require prompt veterinary care. Cats with additional symptoms such as vomiting, yellow skin or gums, decreased appetite, and lethargy require immediate veterinary care, as these are symptoms associated with life-threatening diabetic complications.

Some symptoms indicate serious, life-threatening diabetes-associated conditions, such as diabetic ketoacidosis.

In addition, the smell of ketosis on the breath, similar to the scent of acetone or fingernail polish remover, is a sign of diabetic ketoacidosis, which is an emergency.

The exact reason cats develop diabetes is often unknown. Trends in the occurence of diabetes mellitus are shown to correlate with:

• Obesity
• Age 7 years or older
• Male cats
• Physical inactivity
• Use of steroids to treat other illnesses
• Breed predispositions, particularly in Burmese cats

The most significant of these risk factors is obesity, as obese cats are four times more likely to develop diabetes relative to cats who maintain a lower body weight.

Weight loss occurs in spite of eating sufficient or normal amounts of food. This is due to the cells’ inability to absorb glucose to carry out their normal functions. This lack of response stimulates the body to use up fat stores to produce more glucose. This leads to a cycle that quickly depletes fat stores, creates elevated blood sugar levels, and leaves cells throughout the body starved for energy.

High blood glucose also causes the kidneys to release a higher volume of urine, resulting in increased urination. Not only does this increase urination, it also causes dehydration due to water loss. Cats increase their frequency and amount of drinking to compensate for this change, but still end up showing clinical signs of dehydration.

Diabetes mellitus causes consistently elevated glucose levels in the blood and urine. Routine blood and urine tests are used to identify glucose levels along with other underlying conditions associated with diabetes, such as liver disease. In some cases, more specific blood and urine analysis may be indicated where results are inconclusive.

Treatment of diabetes primarily focuses on reducing blood glucose concentration. Insulin injections deliver a large amount of insulin to the cells, which overcomes their insulin resistance and signals them to absorb glucose as normal. These insulin injections are given at home every 12 hours.

Determining the correct dosage of insulin is critical to successful management of diabetes. Administration of too little insulin fails to control the disease, while too much insulin results in hypoglycemia, which can be immediately life threatening. The amount of insulin required depends on several factors, including the cat’s weight and diet.

Successful management of feline diabetes requires ongoing monitoring and treatment adjustments using a combination of at-home and in-clinic techniques under veterinary direction.

Nutritional therapy is also critical for diabetic cats. Frequent, small meals of low-carbohydrate, high-protein diets are essential for optimizing management of blood glucose levels. Calorie restriction is also essential to keep body weight down. With appropriate nutritional management, some diabetic cats no longer require insulin injections.

Many cats with diabetes live long, healthy lives with appropriate management. Similar to human diabetes, there is no cure for feline diabetes. Many cats that receive appropriate treatment enter periods of diabetic remission. During these periods, the cat does not require supplemental insulin and regulates blood glucose on its own. These cats still require close monitoring and management, as a recurrence of diabetes can occur at any time.

Diabetes is not contagious. Since the root cause is unknown, it is not possible to prevent diabetes. The strong correlation between diabetes and obesity suggests that maintaining a lower body weight is likely to reduce the risk of a cat developing diabetes overall. This is achieved by feeding controlled portions of a vet-approved diet and preventing access to human foods and excessive servings of treats combined with play and exercise.

Diabetes is the second most common endocrine disorder of cats. It is estimated that up to 1% of cats develop diabetes during their lifetime.

• Insulin injection
• Dietary management