Diabetes Mellitus

Diabetes mellitus (sugar diabetes) is a common endocrine disorder in middle- aged to older cats. There is a higher incidence in overweight cats, and males outnumber females 1.5 to 1. Insulin is a hormone produced by the pancreas that allows glucose (sugar) to be utilized by the cells in the body. Body cells need glucose as fuel just as automobiles need gasoline to function.

There are two types of diabetes mellitus in humans and cats. In Type I, also known as insulin dependent diabetes mellitus (IDDM), the pancreas is unable to produce insulin and the patient will need life-long insulin replacement. In Type II, also known as non-insulin dependent diabetes mellitus (NIDDM) the pancreas may retain some ability to produce insulin but the body cannot utilize it properly. This is usually caused by obesity. Certain drugs and other disease processes may also lead to NIDDM. A few of these patients will periodically not require insulin injections. However, most of these cases, known as transient diabetes, will eventually progress to IDDM.

Regardless of the type of diabetes, the cells are not receiving adequate glucose. This sets off a series of bodily responses to try to increase movement of glucose into the cells. Among these responses are increased appetite, utilization of glucose stores in the body, and the production of glucose from other sources such as muscle and fat. This leads to weight loss.

A small percentage of cats will become ketoacidotic. This is a serious and life-threatening syndrome caused by the production of ketone bodies in the liver. The ketones are produced when the body attempts to metabolize fat and protein in an effort to manufacture more glucose. This process causes acidosis of the blood and electrolyte disturbances which can lead to death.

Excess glucose in the blood will "spill" into the urine carrying water with it. This excess urine production is known as polyuria. To prevent dehydration, the cat will increase his water intake (polydipsia). Weight loss is always present despite increased appetite (polyphagia). Often an owner will think the cat’s weight loss program is finally working. As the disease progresses vomiting, loss of appetite (anorexia), weakness, dehydration, hair and skin problems, kidney and liver disease, cataracts, and potentially ketoacidosis may become evident. In rare cases, the cat will develop a nerve disorder where he walks down on his hocks ("ankles"). This may or may not resolve with treatment.

Elevated blood glucose (hyperglycemia), glucose in the urine (glucosuria), and weight loss are needed to diagnose diabetes mellitus. All of these must be present because cats are prone to stress hyperglycemia due to epinephrine (adrenaline) release. A thorough physical exam and blood testing are needed to assess the overall health of the patient and rule out other conditions.

The treatment of diabetes mellitus in the cat initially involves a commitment of time and dedication. Management of a diabetic cat can be frustrating, especially early on. However, it can lead to a stronger owner-pet bond and be a very rewarding experience. With proper therapy, your cat can have a happy, long, and comfortable life. There is a lot to understand about the disease and its management. The following sections will provide important information regarding the care of your diabetic cat.

Oral medications which lower blood glucose are not the ideal treatment for most cats, although it is the only option for some clients. Occasionally, one of the oral drugs will be used along with insulin.

Normally insulin is needed to regulate the diabetes. Humulin Ultralente insulin is selected first because it has the potential to regulate glucose levels for up to 24 hours. This fits into most peoples’ lifestyles. Unfortunately it is often necessary to give the ultralente twice a day or switch to a different insulin (usually Lente or NPH also given twice a day).

You will be instructed how to draw the appropriate amount of insulin into the syringe and how to give the injection. It is advisable that all family members or friends that will be assisting in the administration of insulin be present.

5. Inspect the syringe for bubbles. Bubbles take up space. Therefore, your cat will not be receiving the correct amount of insulin. Another technique is to quickly draw back on the plunger and draw up slightly more insulin than needed. Gently tap any bubbles to the tip of the syringe and push the bubbles and excess insulin back into the bottle. If bubbles remain, push all the insulin back into the bottle and try again. With practice, this is easy to do. If the cat is not ready for the injection, carefully recap the needle. If the syringe sits for 30-60 seconds, gently roll it between your palms to resuspend.

6. For some people it will be easier to have the cat on a counter top or table. At least initially, offer the cat a small amount of canned food and give the injection while he is eating. You may prefer to train the cat that he will get his food or treat after the injection. The actual injection can usually be done by just one person. Some prefer to have a helper rub the cat’s head to distract it. The needle is so small that the cat usually does not feel it.

7. Remove the cap from the needle. Hold the syringe in your right hand (left - if you are left handed). Practice to become comfortable holding the syringe.

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8. Pick a fold of skin and gently lift away from the body to form a tent. Try to pick a different spot each day. The skin does not have to be cleansed with alcohol because it may cause stinging and you cannot properly sterilize the hair and skin anyway. Moreover, many cats associate the smell of alcohol with unpleasant visits to the doctor.

9. Push the needle into the skin quickly. It should be directed parallel to and along the body. Be careful not to stick yourself. Also do not be discouraged if the needle goes in one side and out the other. It happens occasionally to all of us. Make sure your thumb is not on the plunger as you push into the skin. If the cat moves or you are nervous you may push the plunger inadvertently.

Diet is also an important part of the management of diabetes. Increased amounts of fiber slow the rate of glucose absorption from the intestine and minimize the glucose surge in the blood after a meal. The fiber is also an aid in reduction or maintenance of body weight. The diets recommended are Hill’s Prescription Diet w/d and r/d, CNM-OM Formula, and Select Care HiFactor Diet. All these foods contain insoluble fiber and may lead to constipation, so the addition of sugar-free metamucil may be needed as a preventative measure. Often the cat will become "tired" of a high fiber food and you may need to switch to a different one. Some cats will do well on a mixture of the above foods. If your cat will not eat these foods, metamucil or another psyllium product may be added to its normal food to get the benefit of increased fiber. If it is recommended that your cat loose weight, this weight loss must be gradual. To prevent hepatic lipidosis (fatty liver disease), an adequate intake of calories is crucial. The cat should not lose more than one ounce per week, however the weight loss may be more rapid until the diabetes is under control. If at the time of diagnosis your cat is too thin, a high calorie low fiber food such as Prescription Diet c/d will be recommended until the ideal body weight is achieved.

The cat’s normal feeding habits must be considered when formulating a diet plan. Ideally, he should eat small frequent meals to prevent wide fluctuations in the blood glucose. If the cat is a nibbler, the appropriate amount of food for a 24 hour period may be left out. This is the ideal situation. If your cat is gluttonous, he should be fed small frequent meals. If this is not possible, he may be fed twice a day. Give one half of his daily requirement at the time of the injection and the other half 8-12 hours later to coincide with maximum effectiveness of the insulin. If insulin is being given twice a day, give one half at the time of each injection. A small amount of treats is usually acceptable, but should remain consistent on a daily basis.

Ketoacidosis, as previously mentioned, is a severe and potentially fatal complication of untreated or poorly controlled diabetes mellitus. These cats must be hospitalized and started on intravenous fluids. The objective of treatment is to rehydrate, decrease the acidosis of the blood, correct electrolyte abnormalities, and decrease the blood glucose levels to prevent further production of ketones. Often these cats must be referred to one of the areas 24 hour critical care centers. Many times there is another disease process causing this complication.

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1. Insulin does not have to be constantly refrigerated. It is stable for 30-60 days if kept from temperature extremes and sunlight. Since only a small amount of insulin is needed, we recommend refrigeration so the insulin will remain potent until the expiration date.

3. When purchasing a new bottle of insulin, please verify it is the correct type.

4. Discard the bottle of insulin when the fluid level is even with the bottom of the label. This is necessary because it is impossible to adequately resuspend the insulin perfectly each time. Therefore, the last insulin in the bottle may be either too concentrated or too weak. If after a long period of good regulation, the cat suddenly develops clinical signs of diabetes or hypoglycemia, check the insulin level in the bottle and the expiration date. If in doubt, get a new bottle.

5. If care is taken with the needle and syringe, it may be used several times until it becomes dull or is contaminated. Never touch the needle or lay it down without having the needle cover on it.

6. Discard the needles and syringes in a container such as a plastic milk bottle and return it to us for proper disposal. Hazardous wastes are incinerated by a licensed and certified medical waste disposal company. There is a small fee for this service.

1. We recommend you keep a daily log. Your observations are as critical in the evaluation of your cat as our physical examination and glucose monitoring.

2. Monitor his water consumption - i.e., are you adding more or less water to the dish.

3. Monitor the amount of urine produced. If you use clumpable litter, note whether the clumps are getting larger or smaller. Because uncontrolled diabetic cats produce such large volumes of urine, you should be able to notice less overall urine in the boxes even in a multiple cat household.

4. Does he urinate and drink more at night? This may indicate the insulin is not providing 24 hour control.

6. Watch for vomiting, changes in stool frequency and consistency, and the overall attitude of the cat.

7. Consider purchasing a glucose monitor to use at home. Most of the time we are able to evaluate glucose regulation during examination. However, it is often difficult to obtain a non-stressed reading in the hospital. A few cats become so stressed that the result is suspect. We recommend Accu-Chek Advantage. This particular monitor will give values up to 600mg/dl. Other models rarely go above 250-300 mg/dl. If you are comfortable with this, we will instruct you how to collect a small amount of blood from the ear.

8. In certain cases, you may be asked to collect urine at home to test for glucose and ketones or drop the sample off at our clinic. This is not done on a regular basis. However, in difficult cases it may provide valuable information. To collect urine at home, you may try to slip a shallow container under the stream of urine. If only glucose and ketone readings are needed, you can hold the test strip in the stream of urine. Alternately, you may provide the cat with a clean litter box with a small amount of shredded paper instead of litter. If all else fails, it may be necessary for us to collect the sample.

9. Consistency in the timing of the insulin injections and caloric intake will make regulation of the blood glucose easier. A consistent amount of exercise is also advisable; however, this is unrealistic in most cats.

The typical glucose range in a normal cat is 80 to 150 mg/dl. The goal of glucose regulation in the diabetic cat is to maintain the blood glucose levels between 100 to 300 mg/dl throughout the day. Within this range, the cat will be showing minimal signs of disease and the more serious side effects of diabetes (liver and kidney disease, cataracts, etc.) will be prevented. When insulin therapy is initiated, we will need to evaluate the cat every 5-7 days. At this time a blood glucose test is run, body weight is recorded, questions and problems are addressed, and insulin adjustments are made. Additional tests or medications may be needed on an individual basis. Normally it takes 4-6 weeks to evaluate the diabetic control. If regulation has not been achieved, additional testing will be required. Based on the test results, an increase in the insulin dosage (to twice a day) or a change of insulin may be warranted.

1. Glucose curve - During this test, the cat is admitted to the hospital and glucose values are obtained every 1-2 hours. The purpose of this testing is to determine the extent to which the insulin lowers the blood glucose level, if at all. We can perform a 12 hour test in our clinic. If a longer test is indicated, we will refer you to a 24 hour facility. Performing the test at home is also a good alternative. Unless instructed differently, give the morning insulin and food on the day of the testing. Drop off should be between 7:30 to 8:00 AM unless the insulin is normally given later than this. If the cat has food available all day, please bring the appropriate amount of food. If the cat is on twice a day insulin and the next dose is due while the cat is still with us, please bring the insulin with you. He will be dismissed just prior to closing.

Drawbacks to this test - As previously mentioned, cats are easily stressed and adrenaline can cause drastic increases in blood glucose levels even in non-diabetic cats. In these cases, stress hyperglycemia may be 300-400 mg/dl. Often the insulin will not produce the expected glucose-lowering effect and we have to determine if this is stress-induced or a resistance to the insulin. Other times we document an earlier than expected peak effect or dangerously low glucose levels before the body responds by producing excess glucose. If the cat normally nibbles his food through the day and does not eat while hospitalized, this may allow for lower than normal glucose values.

2. Fructosamine - This is a substance formed by the interaction of glucose with albumin which is a protein in the blood. This provides information on the glucose levels over the previous 1-3 weeks. This value is not affected by stress of a hospital visit. Once a cat is stabilized, this test is performed every 2-4 months.

3. Other considerations - Often other inflammatory and infectious disease processes may make it difficult to regulate the blood glucose. The two most common problems are dental disease and infection of the urinary tract. Often a urine culture is performed early on and if there is a suspicion of infection, a course of antibiotics is given. Once a diabetic cat is stable enough to have anesthesia, almost all newly diagnosed patients will need to have a dental prophylaxis. Usually extractions are necessary. The excess glucose in the blood provides a wonderful food source for bacteria. It is also known that chronic diseases such as diabetes mellitus will suppress the immune system. For diabetic cats that cannot be regulated with insulin therapy, there are several rare diseases that will need to be ruled out.

This insulin reaction is due to a marked decrease in the blood glucose. If your cat is receiving once a day insulin, this is most likely to occur 8-12 hours after the injection. However, it can happen anytime. The same is true for cats on twice a day insulin. Signs include lethargy, listlessness, weakness, incoordination, seizures, and coma. If the cat is alert enough to eat, offer a high calorie canned food and allow him to eat as much as he wants. You may need to offer the food in small amounts over 30-60 minutes to prevent vomiting associated with rapid food intake. If signs do not improve in 15-30 minutes, call us or one of the after hours emergency clinics immediately. If the cat responds, please contact us before giving the next dose of insulin. If he will not or is unable to eat, rub 1-2 tbs. of Karo syrup on his gums (be very careful if he is seizuring). Karo syrup should be kept for this purpose. Once this is done, call our clinic or the emergency clinic immediately and advise that you are on your way.

Many times hypoglycemia can be prevented by using a little common sense. If you notice that your cat is consistently acting sluggish or "off" at certain times of the day, you should schedule a glucose check at that time. He may be receiving an overdose. Also, if he is displaying signs of illness such as vomiting, not eating, listlessness, lethargy, etc., you should skip the scheduled dose until you contact us. Administering insulin to a cat that does not feel well enough to eat is probably the most common cause of a hypoglycemic episode. The cat should be evaluated because these are the same symptoms he will exhibit when his blood glucose level is dangerously high.

Initially, taking care of a diabetic cat seems overwhelming. There is a lot to know and understand, and often treatment adjustments are required. However, you and your sense of observation are the most important part of the management of your diabetic cat. Most cats can be successfully treated. Once he becomes regulated, you can expect to spend only several minutes a day on this loving task. Your commitment will be rewarded with years of healthy, happy companionship. Good Luck.

1. Insulin will be given once or twice a day. If given once a day, it should be administered in the morning.

2. The feeding schedule should be the same as before the cat became diabetic. A diet change will probably be necessary and if obese, he will be encouraged to lose weight.

3. The cat will need to be examined every 5-7 days approximately 8-12 hours after the morning injection for a minimum of 4-6 weeks. Insulin dosages will be adjusted during these visits.