Feline diabetes mellitus—The disease
What is feline diabetes mellitus? Diabetes mellitus is a complex, fairly common disease, in which a cat’s system either doesn’t produce sufficient insulin, or has insulin resistance. During digestion, fats, carbohydrates, and proteins that are consumed as part of the diet are broken down into smaller nutrients that are utilized by the cells in the body during metabolism. One component of carbohydrate digestion is glucose, the fuel that provides the energy needed to sustain life. Insulin is the hormone, produced in the pancreas, which is responsible for regulating the flow of glucose from the bloodstream into the cells of the body. If insulin is deficient or ineffective, body fat or protein may be used as alternative sources of energy.
How is diabetes mellitus diagnosed? Diabetes mellitus is diagnosed based on the cat’s clinical signs, a full physical examination (obesity is definitely a risk factor), laboratory results, and especially persistent and abnormal hyperglycemia and glycosuria. Once diagnosed, an immediate treatment plan should be implemented.
What is involved in treatment? Each diabetic cat is an individual, and each presents with its own needs and responds differently to treatment. The mainstay of treatment is the need for an exogenous source of insulin and dietary modification. Successful management of the diabetic includes no or minimal clinical signs, with an owner perception of improved quality of life, no complications, and avoidance of hypoglycemia. In some cats, remission may be possible, usually with early intervention and successful dietary changes, but many may revert back to a diabetic state.
When starting the cat on insulin, some are easy to regulate; others are not. Some can be treated with oral medications, while others require insulin injections. Regardless of this variability, all diabetic cats do best with consistent medication, consistent diet, and a stable, stress-free lifestyle.
Insulin. Most diabetic cats require insulin injections administered under their skin twice daily. The injections can be given at home, preferably at the same time each day.
Oral Hypoglycemic Medications. Healthy diabetic cats can sometimes be successfully treated with glipizide, an orally administered hypoglycemic medication that lowers blood glucose. Although glipizide works for some diabetic cats, most require insulin injections to successfully control their disease. In addition, the administration of oral medication on a long-term basis is difficult for many cats and their owners; insulin injections may be a better choice for them.
Diet. In addition to medication, an important step in treating diabetes is to alter the patient’s diet. A higher-fiber, high-complex carbohydrate diet not only can achieve weight loss if necessary, but is believed to help control blood sugar levels after eating. Other diabetic cats respond well to high protein, carbohydrate-restricted diets. Although diabetic cats have been successfully managed with both types of diets, some cats respond better to higher-fiber diets and others to higher protein, low-carbohydrate diets. Trial and error can help determine the best diet for your patient.
What is the prognosis for a diabetic cat? If the causative etiology of the diabetes mellitus is identified and a plan to treat and manage put into place, there is a reasonable expectation that the symptoms can be controlled with long-term quality of life. In the absence of complications or concurrent diseases like CKD or pancreatitis, remission may be a goal. Nonetheless, successfully managing a diabetic cat requires much dedication and communication between the veterinary healthcare team and the pet-owner client.