Diabetes mellitus is one of the most commonly diagnosed metabolic diseases in cats. It is a complex, disease in which a cat's body either doesn't produce enough or doesn't properly use insulin. During digestion, the fats, carbohydrates, and proteins in the diet are broken down into smaller components that can be utilized by cells in the body. One component is glucose, a sugar, which is the fuel that provides the energy needed to sustain life.
Insulin is a hormone produced in the pancreas, and is responsible for regulating the flow of glucose from the bloodstream into the cells of the body. Diabetes develops when beta cells of the pancreas lose function, or when the body becomes resistant to insulin - sometimes as a consequence of obesity. When insulin is deficient or ineffective, the cat's body starts breaking down fat and protein stores to use as alternative energy sources. As a result, the cat eats more yet loses weight. Additionally, the cat develops high levels of sugar in the bloodstream, which is eliminated in the urine. Sugar in the urine leads to excessive urination and thirst.
Diabetes affects approximately 1 in 400 cats. Although any cat may be affected, diabetes most often occurs in older, overweight cats greater than six years old. Male neutered cats are more commonly affected than females. The exact cause of the disease in cats is not known, although obesity (the major predisposing condition), chronic pancreatitis, other hormonal diseases (hyperthyroidism, Cushing's disease, and acromegaly), and certain medications (corticosteroids like prednisolone) have all been linked to the disease. Because obesity is the most common risk factor, overweight cats need to be watched closely for the development of diabetes mellitus.
Diabetes mellitus is generally divided into two different types in cats: insulin-dependent diabetes mellitus (IDDM), and non-insulin-dependent diabetes mellitus (NIDDM). Approximately one-half to three-quarters of diabetic cats have the insulin-dependent form and thus require insulin injections as soon as the disease is diagnosed. The remaining diabetic cats have NIDDM, however, most cats ultimately require insulin injections to control their disease.
Increased thirst (polydipsia)
Increased urination (polyuria)
Significant weight loss
Poor coat condition
Weakness in the hind legs/walking 'flat footed' with the hocks (ankles) on the ground (Diabetic neuropathy)
Left untreated, diabetes will shorten a cat's lifespan. A dangerous, sometimes fatal condition called ketoacidosis may develop. A cat who has untreated diabetes will eventually show the following signs:
Complete loss of appetite
If your cat exhibits any of the above symptoms, seek veterinary medical attention as soon as possible.
Many of the signs of diabetes are also common to other conditions, so complete bloodwork, and a thorough medical history, as well as a physical examination will be necessary. Diabetes mellitus is diagnosed based on the cat's clinical signs, physical examination findings, and laboratory test results. A blood chemistry analysis, complete blood count (CBC), and a urinalysis will detect the presence of abnormally high levels of glucose (sugar) in the blood and urine. Persistence of these findings is confirmatory for diabetes mellitus. Once diabetes has been diagnosed, immediate treatment is necessary.
To determine whether your cat needs insulin, we will measure blood glucose levels. If the glucose level is only slightly above normal, we may suggest dietary management and oral hypoglycemic agents before resorting to insulin injections. However cats with persistent and pronounced hyperglycemia (high blood sugar) usually require insulin. A majority of cats fall into this category.
Diabetes treatment is based on the severity of the disease. Cats with ketoacidosis require prompt intensive care, which includes fluid therapy and short-acting insulin injections to rapidly decrease blood sugar levels. For cats that are not severely ill, a treatment plan that includes insulin injections along with dietary changes will be instituted.
Each diabetic cat is an individual, and each responds differently to treatment. Some diabetic cats are easy to regulate, while others are not. Some can be treated with oral medications, while most require insulin injections. Some have transient, diabetes - meaning reversible with the passage of time, while others will require treatment for the remainder of their lives. Different cats respond best to different types of insulin. Regardless of this variability, all diabetic cats do best with consistent medication, consistent feeding, and a stable, stress-free lifestyle.
Most diabetic cats require insulin injections administered under the skin twice daily. The injections are given at home, preferably at the same time each day. You will be shown how to give these non-painful injections before bringing your cat home from the hospital. Because each cat is different, the type of insulin, dose, and frequency of administration needs to be determined for each individual animal. Initially the insulin dosage may change frequently while your cat is becoming regulated. Blood glucose curves, 5-6 hour post insulin blood sugar levels, and other intermittent blood tests and urine sugar measurements will be used to keep your cat on the right track. After insulin therapy is initiated and the cat's blood sugar is regulated, the clinical signs related to diabetes should disappear.
In addition to medication, an important step in treating diabetes is to alter your cat's diet. Obesity is a major factor in insulin sensitivity, so if your cat is overweight, you will need to help him lose weight gradually. A safe weight-loss program, in which your cat loses weight gradually will be instituted. Research has proven that diabetic cats respond well to high protein, carbohydrate-restricted diets. There are several prescription diets available including Purina DM and Hill's m/d which are available at the hospital.
Your cat's feeding routine is also important. While many cats are "free-choice" feeders (food is left out for them to eat whenever they want), this may not be the best routine for a diabetic cat. Ideally, a cat receiving insulin should be fed half its daily food requirement at the time of each injection, with the unconsumed remainder available throughout the day.
Many diabetic cats will have occult (no outward sign) urinary tract infections due to the high levels of sugar in the urine. That environment is ideal for bacteria to grow and most cats with diabetes need to be treated with antibiotics to clear the infection.
Hypoglycemia (low blood sugar) is a potentially dangerous complication, usually caused by a relative overdose of insulin. Hypoglycemia signs include:
lack of coordination/'drunken stagger'
Left untreated, hypoglycemia can be fatal. If hypoglycemia develops, the cat should immediately be offered its normal food. If the cat is unable to eat, rub some corn syrup or maple syrup onto the gums. If the cat can swallow, the corn syrup can be administered slowly by syringe into the mouth. Never force fingers, food, or fluids into the mouth of a convulsing or comatose cat. After attempting to feed or orally administer corn syrup, bring your cat to the hospital immediately for further treatment of hypoglycemia.
To avoid episodes of hypoglycemia, always make sure your cat is interested in eating before you administer insulin. Keep careful track of injections so that your cat doesn't get a double dose from two separate caretakers. When in doubt, no insulin is better than too much.
Because your cat's insulin requirements may change over time, periodic checking of a blood glucose level 5-6 hours after receiving insulin, or checking serum fructosamine levels is essential. Fructosamine tests will 'look back' over the last two weeks and give an average blood sugar assessment. If the cat spends most of the time in the ideal blood sugar range, the fructosamine level will be consistent with good regulation. If the cat is not well regulated the fructosamine level will be too high, and the dose or type of insulin may need to be adjusted.
Please seek veterinary evaluation and treatment at the first reappearance of diabetes signs (increased thirst, weight loss, increased appetite, or increased urination) as this may mean an adjustment in insulin therapy may be needed.
There is no cure for diabetes mellitus. However, some diabetic cats may lose the need for insulin injections, months or years after diagnosis. It has been shown that a change in diet and weight loss are the biggest contributing factors in a cat having transient diabetes, so be sure to continue giving your cat the newly prescribed diet. If diabetes has resulted from obesity, it is likely to improve a great deal, or even completely resolve once the cat's weight is under control. If obesity or some other disorder is not a factor, the diabetes probably will not go away, however it can be successfully managed. The serious chronic complications that afflict people with diabetes mellitus (such as kidney disease, blood vessel disease, and coronary artery disease) are uncommon in diabetic cats. Once glycemic control is attained with proper treatment and home care, a diabetic cat can live many happy, healthy years. Nonetheless, successfully managing a diabetic cat requires much dedication on the part of the owner and regular communication between you and your veterinarian.
If your cat is exhibiting signs of diabetes mellitus, please call 516-379-6200 to schedule a diabetes screening appointment today.