Diabetes in Dogs And Cats

My name is Caralampio


Ron Hines DVM PhD

I wrote this article some time ago, but search engines still default to it.

So instead of reading it: If you have a diabetic cat, go here.

If your pet is a dog, go here.


What Is Diabetes ?

Diabetes mellitus is a disease of your pet's endocrine gland system. One of these endocrine glands, the pancreas, is responsible for regulating your pet's blood sugar level.

There are two forms of diabetes, type 1 and type 2. 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. This Insulin is produced by the pancreas gland which is nestled among the loops of your pet's small intestines. A situation similar to Type l diabetes is the most common form in dogs. A situation similar to Type ll diaetes is the most common form in cats.

Two things influence your pet's susceptibility to diabetes - its weight and its genetics. As in humans, pets that are overweight are more susceptible to developing Type 2 diabetes. Certain breeds also appear more susceptible to developing diabetes. These include miniature schnauers, toy and miniature poodles, samoyeds, australian terriers, elkhounds, dachsunds, westies, and pugs (ref) as well as burmese cats (ref). Other breeds, like german shephers, pit bulls and golden retrievers rarely develop the problem.

Neutered dogs are considerably more likely to develop type 2 diabetes than un-neutered pets, quite likely due to the known tendency for neutered pets to become fat , but just being a female pet apears to add risk as well.

The mean age that dogs develop diabetes is 7-9 years. with cats tending to develop the disease a year or two later in life.


Your pet's many endocrine glands work in tandum, often relying on the hormonal signals of one gland to stimulate the activity of another. Your pet's testicles or ovaries produce hormones that have profound effects on its other endocrine glands, so surgically removing them has consequences other than serility. We know that pets thats show evidence of adrenal or pituitary endocrine gland disease are at a higher risk of developing diabetes as well.

Many veterinarians and animal nutritionists suspect that in cats, a diet too rich in carbohydrates increases a pet's risk of developing diabetes. We already know that the level of carbolydrate in feline diets influences their post-feeding blood glucose levels. (ref)

Insulin is a hormone produced by the body. Insulin works by binding with receptors on cells throughout the body 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 bad things to happen. When your pet's blood sugar is about twice its normal level in its blood, some of it will spill over into its urine. In dogs, this occurs when their blood sugar level exceeds about 180mg/dL ; in cats when it exceeds 280 mg/dL. You can find your pet's normal blood values here.

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

What Causes Diabetes ?

As I previously mentioned, diabetes tends to occur in pets that have been too fat. So you have a great deal of control over the situation if you and your family can be strict enough in regulating the amount of food and the kind of foods your pet eats. It takes enormous will power not to over-feed the pets we love when they begs for more food and treats than is healthy. There are specialty diets designed specifically for diabetes cats.

Diabetes occurs when pancreatic islet cells called beta cells are destroyed. Destruction of these cells occurs due to chronic pancreatitis or autoimmune disease in which the body attacks its own cells. Diabetes also occurrs in pets that have over active adrenal glands (hyperadrenocorticism) or have received large doses of corticosteroids or sex hormones.

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 the glucose in. This can be a problem 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, elevatted blood pressure and. high triglycerides. . Many veterinarians have begun to use newer products to treat this. In cats, the troglitazone (Rezulin) has shown promise.

What Signs Might I See In My Pet ?

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 drinking more and urinate very frequently. these 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 develop 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.

How Will My Veterinarian Diagnose Diabetes In My Pet ?

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, Cushing's 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.

What Treatments Are Available For My Pet ?

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, insulins derived from animal pancreas work better in dogs and cats than the bio-engineered insulins available for humans. For a time, these older insulin forms because difficult to get. But a porcine insulin zinc suspension is now available again.

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. t is best to feed the pets at the time the insulin shot is given. Avoid using semi-moist diets because they 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 Choices:

Scientific studies, performed in 2005 suggest that cats, which in Nature are strict carnivores, do not produce sufficient Glucokinase and Hexokinase, liver enzyme that are necessary for the metabolism (use) 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 For Diabetes:

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 strips 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.

For your pet to do well over a long period, it is very important that you monitor it's blood sugar level at home and adjust the insulin dose accordingly. The best way to do this is to purchase a hand-held blood glucose meter designed specifically for dogs and cats. Abbott Laboratories' AlphaTRAK, is an apparatus designed for this. The problem with using meters designed for humans is that they were designed to work with human red blood cells which are larger than dog and cat red blood cells. This means that the blood sugar reading that you obtain using a human meter will be lower than they actually are. Some people use human meters and adjust the readings upward using tables. The human One Touch Ultra meter has been used in this way.

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 That Can Occur:

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.

What Can I Do To Help Prevent Diabetes In My Pet ?

Feed your pet a nutritious diet. Do not over-feed your pet. Just like humans, overweight pets are at higher risk of developing diabetes, arthritis and a host of other problems.

One of the causes of obesity in our pets is probably neutering them too young. Un-neutered pets can get too plum too. You just have to control what they eat and how much they eat. Be sure they get plenty of exercise.