Ron Hines DVM PhD 2/16/06

Diabetes mellitus is a disease of the endocrine system. Type 1 diabetes is caused by a deficiency of insulin -- the hormone that regulates how sugar is absorbed and utilized by the cells of the body. Highest occurrences are in dogs and cats between the ages of 5 to 7 years. Female dogs appear to be more susceptible but both sexes of cat are equally affected. Most affected dogs and cats were obese. It is the most common hormonal disorder in dogs and second only to hyperthyroidism in cats. Among dogs, poodles, dachshunds miniature schnauzers and west highland white terriers have a high incidence of the disease.

Insulin works by binding with receptors on cells much like a key fits into a lock. Once the insulin has “unlocked the door”, glucose can cross over into the cell from the blood. Once inside the cell, glucose is either burned by the cell for energy or stored for future use as glycogen. Without insulin, sugar accumulates in the bloodstream causing a number of undesirable effects. When sugar is about twice its normal level in the blood, some of it spills over into the urine.

Sugar in the urine causes increased urine production and thirst. These pets also become hungrier because they can not utilize the sugar present in their blood. As the disease progresses, waste products called ketones accumulate and cause depression, vomiting and dehydration. If the disease is not treated coma and death may occur. We can not cure diabetes yet but by administering insulin the disease can be controlled and damage can be kept to a minimum.

How The Disease Occurs:

Diabetes tends to occur in creatures that are previously obese. These animals include cats, dogs, humans and monkeys. So you have a great deal of control over the situation, if you can bare to see your pet beg for more food than is healthy.

Diabetes occurs when pancreatic islet cells called beta cells are killed. Destruction of these cells occurs due to chronic pancreatitis or autoimmune disease in which the body attacks its own cells. Diabetes may also occur in pets that have over active adrenal glands (hyperadrenocorticism) or have received large doses of corticosteroids or sex hormones. Excess weight is a risk factor in both dogs and cats.

Type 2 or Insulin-resistant diabetes is a phenomenon in which a normal or abnormally high amount of insulin is present in the blood stream but can no longer “unlock the door” to cells to allow glucose in. This often occurs in cats. Muscle cells, in particular react sluggishly to the desirable action of insulin and are starved for energy. In this condition, eating a hearty meal is followed a group of symptoms including elevated blood sugar, blood pressure and. high triglycerides. . Many veterinarians have begun to use newer products. In cats, the troglitazone, Rezulin, shows promise.

Signs Of The Disease:
The onset of diabetes is usually very gradual and easily missed by the owner until it is quite advanced. The first thing most owners notice is that the dogs or cats is drink more and more water and urinate very frequently. Pets eat well but may actually loose weight. Cataracts of the eyes and general debility are also common signs. They are common in dogs but rare in cats. When blood glucose exceeds 180 mg/deciliter in dogs and 240mg/decileter in cats, sugar spills over into the urine. Diabetic pets have an increased susceptibility to bacterial and fungal infections. Chronic infections of the bladder and skin, pneumonia and prostate infections commonly occur. Fatty, enlarged livers are another sign of the disease.. Luckily, the nerve, retinal and kidney damage so common in people less frequently in pets. This may be because a pet's life span is shorter. Cataracts in diabetic dogs, however, are common. Approximately 20% diabetic dogs develope signs of retinal hemorrhages or microaneurysms (small red dots in the retina), Retinal function in these dogs appears to remain unchanged. When these dogs loose vision it is because of cataracts which can be surgically removed through a process called phacoemulsification.d

Diagnosis:
Diabetes is a relatively easy disease to diagnose. Fasting blood sugar in dogs and cats should be between 75 and 120mg/decileter. When it is over 200mg/decileter and other blood parameters are normal diabetes may be the cause. The transient stress of blood withdrawal at the animal hospital and another disease, cushings disease, need to be ruled out. The best current way to rule out stress-induced high sugar in cats is to measure blood fructosamine levels. Fructosamines are stable complexes of carbohydrates and proteins. A single measurement of fructosamine indicates the average glucose concentration over the previous 1 - 2 weeks - not at the moment the blood is withdrawn. Because this gives us a broader view of your pet's sugar levels over time, this assay is helpful in making a firm diagnosis of diabetes well as in monitoring the effectiveness of insulin therapy. Fructosamine values are not influenced by sudden fluctuations in blood glucose such as stress in nervous pets from the visit to the Veterinary hospital or recent food intake. So fructosamine is much more reliable than a single glucose determination. Fructosamine results can be falsely lowered in cats with hyperthyroidism. Normal fructosamine levels are between 100 - 400 umol/l.

Treatment:
Type 1 diabetes in dogs and cats is very similar to juvenile diabetes in people. Going to a human diabetes website will give you ideas you can apply to your pet. Although diet helps to control the disease in pets, once the disease begins, owners will need to administer insulin to keep the disease under control. This is a time consuming process that requires a great deal of dedication on your part. Most pets will require two injections per day of either ultralente or NPH insulin. When the correct dose is established there should be only intermittent low concentrations of sugar in the urine. In general, NPH insulin works best in dogs and ultralente human origin insulin works best in cats
Because no two pets react exactly the same to a given amount of insulin, changes in the dose administered should be done under observation in an animal hospital setting. This is particularly true with small and toy breeds where small dose changes can have major effects on blood glucose levels. I start dogs that weigh less than 30 pounds on 0.5units/pound body weight NPH insulin given once or twice a day. Dogs over thirty pounds begin on 0.25units/pound. Cats begin at 1-2 units of ultralente or PZI insulin (0.1 to 0.5U/lb) as a single morning injection. It is best to feed the pets at the time the insulin shot is given. Avoid using semi-moist diets because the are high in sugar. I have not had success in dogs and cats using oral glucose control drugs such as Glipizide. Once a successful insulin treatment has been established for your pet it needs to continue on it the rest of its life. The key to successful treatment is to keep to the treatment plan.

Female dogs that develop the disease do better when they are spayed. If you exercise your dog set the time and the length of your playtime the same every day.

Diet:

Scientific studies, performed in 2005 (Nestle Purina Nutrition Forum) suggest that cats, which in Nature are strict carnivores, do not produce sufficient Glucokinase and Hexokinase, liver enzyme that are necessary for the metabolism (used) of glucose. Glucose is the end product of carbohydrates absorbed through the intestine. My interpretation of this data is that cats would have a tendency to high blood sugar and subsequent diabetes when fed a diet containing carbohydrates in quantity. Therefore, do not feed cats diets that are high in carbohydrates. Carbohydrates in cat foods are usually derived from plant products. Meat-based diets should contain very little carbohydrate.

You will need to be stricter about when, what and how much you feed your pet. If your pet is overweight begin a slow diet over three or four months to normalize its weight. Weight loss is easier if you feed your pet in three or four discrete meals always at the same time every day. Feed fat pets approximately two thirds of the amount it would eat if food were unrestricted. Feed dry kibble and avoid canned diets. Another approach is to feed high fiber/complex carbohydrate diets designed for weight loss. The high fiber in these diets is also beneficial in diabetes. Some dogs and cats, however, are thin from ketosis by the time the disease is diagnosed. In these pets a high caloric diet should be fed until the pet’s weight returns to normal. CNM, Hills, IVD and Eukanuba all offer diets suitable for diabetic pets.
If you feed three times a day, divide the feeding into equal amounts. Give your first feeding of the morning about a half-hour before its morning insulin injection.

Testing:
During your pet’s initial hospitalization blood glucose levels will be checked frequently. This hospitalization can take as long a week. The first test is generally before the first injection of the morning. To avoid trauma to the arm I may place a multiple-use catheter in the vein. I then check the pet’s blood glucose lever one hour after its injections and at four other points during the day. No two veterinarians use exactly the same protocol. Also, no two pets respond exactly the same to the injections. Each treatment plan will be tailor-made to each pet.

It is very important that you monitor your pet frequently to be sure that the insulin dose you are using is still correct. Do this by wetting a urine test strip, which you purchase at the drug store. These strip tell you indirectly if blood sugar levels have come down to near normal levels. Increase or decrease the pet’s insulin dose according to the results. It is best to keep a diary of results testing the pet at the same time every day.

While you are waiting for your pet to come home, go to your pharmacy and purchase a human glucometer. Lancets to obtain a drop of blood work well around the pet’s nose. Give your pet a small treat after obtaining the blood sample and praise him. I generally suggest that blood be tested first thing in the morning and again at noon and bedtime for a number of weeks. Once the pet is well established in his food and injection routine the evening or afternoon checks can be eliminated. Be sure to keep the insulin in the refrigerator.

Complications:
The most common complication I see in diabetic pets is giving them too much insulin. When this happens the dogs go into hypoglycemic shock. This can be a life-threatening emergency. Hypoglycemic dogs and cats become depressed, weak and stuporous. When this occurs it is usually 3-4 hours after the insulin injection. If this occurs take your pet immediately to a veterinary hospital. On your way, give your pet sugar containing syrup (Karo) or pancake syrup. I give all my clients a small vial of 50% dextrose solution just for such an emergency. Do not give oral sugar to pets that are seizuring and be careful not to get bitten.

Diabetic pets, especially those in which the disease is not being controlled well, are more susceptible to infections. Urinary tract infections are particularly common since the sugar in the urine allows bacteria to grow. These pets need better insulin control and periodic antibiotics. Have your pet’s urine examined at the first sign of blood in the urine or straining.

Care of a diabetic pet is very challenging. You will need a good rapport with your veterinarian. If you are not very compatible with your veterinarian, now would be a good time to search for another. Ask the receptionist how your veterinarian handles after-hours emergencies. Most veterinarians today refer after hours calls to an emergency clinic. If this is the case be sure to ask for their telephone number. If you are dedicated to following the plan your veterinarian works out for you, your pet it should continue to have a happy and long life.

It has recently been found that severely limiting the amount of carbohydrate fed to cats while increasing the amount of protein they eat can go a long way in controlling diabetes. Dry cat chows , even those recommended for diabetes, are generally higher in carbohydrates than canned cat foods so the first thing to do is switch you cat to a canned diet with the highest protein and lowest carbohydrate content available. Blood glucose surges after eating canned foods are generally less than that due to dry cat foods.

A new medication that is being tried in dogs and cats is Lantus® (insulin glargine [rDNA origin] injection) This is a once-a-day insulin manufactured for humans by Aventis Pharmaceuticals. It is the first insulin to offer truly flat insulin levels through the entire day for most humans. Its advantages are once a day administration that keeps blood sugar constant throughout the day.

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