There are two forms of diabetes in dogs: diabetes insipidus and diabetes mellitus. Diabetes insipidus is a very rare disorder that results in failure to regulate body water content. Your dog has the more common type of diabetes, diabetes mellitus. This disease is seen on a fairly regular basis, usually in dogs 7 – 9 years of age or older, many of them overweight. There is a genetic predisposition in some breeds and females are affected twice as often as males. Simply put, diabetes mellitus is a failure of the pancreas to regulate blood sugar.
The pancreas is a small but vital organ that is located near the stomach. It has two significant populations of cells. One group of cells produces the enzymes necessary for proper digestion; the other group (beta cells) produces the hormone called insulin.
TYPES OF INSULIN
In dogs, two types of diabetes mellitus have been discovered. Both types are similar in that there is a failure to regulate blood sugar, but the basic mechanisms of disease differ somewhat between the two groups.
- Type I, or Insulin Dependent Diabetes Mellitus (IDDM): This results from total or near-complete destruction of the beta cells that produce insulin. This is the most common type of canine diabetes. As the name implies, dogs with this type of diabetes require insulin injections to stabilize blood sugar.
- Type II, or Non-Insulin Dependent Diabetes Mellitus (NIDDM): This is different because some insulin-producing cells remain. However, the amount produced is insufficient, there is a delayed response in secreting it, and the tissues of the dog’s body are relatively resistant to it. These dogs may be treated with an oral drug that stimulates the remaining functional cells to produce or release insulin in an adequate amount to normalize blood sugar. Alternatively, they may be treated with insulin. Dogs with NIDDM will ultimately progress to total beta cell destruction and then require insulin injections.
WHAT INSULIN DOES FOR THE BODY
The role of insulin is much like that of a gatekeeper. It stands at the surface of body cells and opens the door, allowing glucose to leave the blood stream and pass inside the cells. Glucose is a vital substance that provides much of the energy needed for life, and it must work inside the cells. Without an adequate amount of insulin, glucose is unable to get into the cells. It accumulates in the blood, setting in motion a series of events that can ultimately prove fatal.
When insulin is deficient, the cells become starved for a source of energy. In response to this, the body starts breaking down stores of fat and protein to use as alternative energy sources. As a consequence, the dog eats more; thus we have weight loss in a dog with a ravenous appetite. The body tries to eliminate the excess glucose by eliminating it in the urine. However, glucose (blood sugar) attracts water; thus, urine glucose takes with it large quantities of the body’s fluids, resulting in the production of a large amount of urine. To avoid dehydration, the dog drinks more and more water.
Thus we have the classical signs of diabetes:
- Weight loss
- Ravenous appetite (Eating more but loosing weight)
- Increased water consumption (Filling the bowl more frequently)
- Increased urination (sometimes urinating in the house)
- Hair coat deteriorates
- Sleeps more or is inactive
The diagnosis of diabetes mellitus is based on three criteria: The classical clinical signs, the presence of a persistently high level of glucose in the blood stream, and the presence of glucose in the urine.
The normal level of glucose in the blood is 80 – 120 mg/dl. It may rise to 250 – 300 mg/dl following a meal or when the dog is very excited. However, diabetes is the only common disease that will cause the blood glucose level to rise above 400 mg/dl. Some diabetic dogs will have a glucose level as high as 800 mg/dl, although most will be in the range of 400 – 600 mg/dl.
To keep the body from losing its needed glucose, the kidneys do not allow glucose to be filtered out of the blood stream until an excessive level is reached. This means that dogs with a normal blood glucose level will not have glucose in the urine. Diabetic dogs, however, have excessive amounts of glucose in the blood, so it will be present in the urine.
The diagnosis of diabetes seems rather simple, and in most dogs it is. However, some diabetic dogs do not meet all the criteria. For these, another test is performed called fructosamine levels. This test represents the average blood glucose level for the past two weeks. It minimizes the influence that stress and eating have on blood glucose levels and can be very helpful in understanding difficult cases.
WHAT IT MEANS FOR YOUR DOG TO BE A DIABETIC
For the diabetic dog, one reality exists. Blood glucose cannot be normalized without treatment. Although the dog can go a few days without treatment and not get into a crisis, treatment should be looked upon as part of the dog’s daily routine. Treatment almost always requires some dietary changes. Whether an individual dog will require oral therapy or insulin injections will vary.
As for the owner, there are two important points: financial commitment and personal commitment.
When your dog is well regulated, the maintenance costs are minimal. The special diet, the insulin and syringes are not expensive. However the financial commitment can be significant during the initial regulation process, especially if complications arise.
In some cases, your dog will be hospitalized for a few days to deal with the immediate crisis and to begin the regulation process. The “immediate crisis” is only great if your dog is so sick that it has quit eating and drinking for several days. Dogs in this state, called ketoacidosis may require a week or more of hospitalization with quite a bit of laboratory testing. Otherwise the initial hospitalization may be only for a day or two to get some testing done and to begin treatment. At that point, your dog goes home for you to administer insulin. At first, return visits are required every 5 – 7 days to monitor progress. It may take a month or more to achieve good regulation.
The financial commitment may be significant if complications arise. We will work with you to achieve consistent regulation, but some dogs are difficult to keep regulated. It is important that you pay close attention to our instructions related to administration of insulin, to diet, and to home monitoring. Consistency is the key to prolonged regulation. The more you keep the insulin, diet, and activity the same from one day to the next, the easier it will be to keep your dog regulated.
Another complication that can arise is hypoglycemia or low blood sugar (glucose); if severe, it may be fatal. This may occur due to inconsistencies in treatment or because some dogs may have infections or other underlying diseases.
Your personal commitment to treating this dog is very important in maintaining regulation and preventing crises. Most diabetic dogs require insulin injections twice daily, at about 12 hour intervals. They must be fed the same food in the same amount on the same schedule every day. If you are out of town, your dog must receive proper treatment while you are gone. These factors should be considered carefully before deciding to treat a diabetic dog. Additional information on diabetes in dogs and cats can be found at the following websites: www.vetsulin.com and www.veterinarypartners.com
Treating a diabetic dog can be a challenge. Some dogs just never seem to stay regulated. However, there are several important concepts that make this process much more likely to be successful.
- Consistency: Our goal is to find an appropriate dose of insulin that will last on a long-term basis. In order to do that, we must eliminate as many variables as possible. In other words, the more things that can stay the same from one day to the next, the easier it is to keep a diabetic regulated. Our goal is to give the same dose of insulin the same time each day, to feed the same food in the same quantities each day, to keep the activity level the same each day, and to keep your dog’s stress level the same.
- Tighter control is more necessary in dogs than in cats but not as tight as in humans. Human diabetics must maintain blood glucose values very close to normal at all times. If they don’t they will develop some disastrous complications of diabetes, such as loss of fingers, toes, feet, and hands, kidney failure, and cataract formation. Some of these complications can also be found in unregulated diabetic dogs. Therefore, as stated above, it is better for the blood glucose to be too high than too low.
- In dogs, mild hyperglycemia (high blood glucose) is always better than hypoglycemia (low blood glucose).
- As the dose of insulin goes up, the blood glucose goes down.
- Food intake causes the blood glucose to rise. Failure to eat allows the blood glucose to fall below normal.
- The primary aims when managing diabetes in dogs are:
- Resolution of the clinical signs of persistent hyperglycaemia and
- Avoidance of insulin-induced hypoglycaemia.
These principles are applied as such: If you are not sure if you gave a dose of insulin or if it was properly injected, do not give it again.
As mentioned, the key to successful treatment is consistency. Your dog needs consistent administration of insulin, consistent feeding, and a stable, stress-free lifestyle. To best achieve this, it is preferred that your dog lives indoors. Although that is not essential, indoor living removes many uncontrollable variables that can disrupt regulation.
The first step in treatment is to alter your dog’s diet. Diets that are high in fiber are preferred because they are generally lower in sugar and slower to be digested. This means that the dog does not have to process a large amount of sugar at one time. If your dog is overweight, a reducing-type diet is fed until the proper weight is achieved, then your dog is switched to a high fiber maintenance.
Your dog’s feeding routine is also important. The average dog prefers to eat about once to twice per day. However, it is still necessary to monitor how much food is eaten each day. The best way to feed a diabetic dog is twice a day. You should have received a diet recommendation for your dog. If you have not received one, please ask for one.
The second step in treatment is to use a drug to control (lower) blood glucose levels. The only choice in dogs is insulin for treatment in dogs. By the time they become a diabetic they have already lost the beta cells that make insulin. Oral medication is designed to make the cells increase their insulin production, however, there are no cells to do this, therefore oral medication is not effective.
Insulin injections replaces the hormone that is missing or made in inadequate amounts. Although many people are initially uncomfortable with the thought of giving injections, there is no other choice for dogs
Many people are initially fearful of giving insulin injections. If this is your initial reaction, consider these points:
- Insulin does not cause pain when it is injected.
- The injections are made with very tiny needles that your dog hardly feels.
- The injections are given just under the skin in areas in which it is almost impossible to cause damage to any vital organ. Please do not decide whether to treat your dog with insulin until we have demonstrated the injection technique. You will be pleasantly surprised at how easy it is.
INSULIN THERAPY AND ADMINISTRATION
Insulin comes in an airtight bottle that is labeled with the insulin type and the concentrations. Before using, mix the contents gently. It says on the label to roll it gently, not shake it. The reason for this is to prevent foam formation, which will make accurate measuring difficult. Some of the types of insulin used in dogs settle out of suspension in a few hours. It if is not shaken properly, it will not mix well and dosing will not be accurate. Therefore, the trick is to shake it vigorously enough to mix it without creating foam. Since bubbles can be removed (as described later), it is more important to mix it well than to worry too much about foam formation.
Insulin is a hormone that will lose it effectiveness if exposed to direct sunlight or high temperatures. It should be kept in the refrigerator, but it should not be frozen. It is not ruined if left out of the refrigerator for a day or two as long as it is not exposed to direct sunlight. However, we do not advise this. Insulin is safe as long as it is used as directed, but it should be kept out of reach of children.
Several types of insulin are used in dogs. Some are made for use in humans and obtained from regular pharmacies. Vetsulin is made specifically for dogs and obtained from veterinarians.
Caninsulin® – a highly purified pork insulin (identical to canine insulin) is now available in the U.S. as Vetsulin. This product is available through veterinarians, rather than at the corner drugstore, and may come to dominate the canine market. It is an intermediate-acting insulin and is a relatively new product.
Your veterinarian will select the proper insulin for you to buy.
Insulin need not be refrigerated but should be kept out of sunlight. It is normal for a small white layer to settle in the bottle after it has been sitting.
Vetsulin has a concentration of 40 units of active insulin crystals per milliliter of fluid. Thus it is called U40 insulin. Insulin made for humans have a concentration of 100 units per milliliter and are called U100 insulin. They are made to be used with their respective types of insulin and must not be interchanged or improper dosing will occur.
DRAWING UP INSULIN:
Have the syringe and needle, insulin bottle, and dog ready. Then follow these steps:
- After mixing the insulin (see previous page), remove the guard from the needle and draw back the plunger to the appropriate dose level.
- Carefully insert the needle into the insulin bottle.
- Inject air into the bottle; this prevents a vacuum from forming within the bottle.
- Withdraw the correct amount of insulin into the syringe.
- When drawing up the insulin, always hold the bottle vertically to avoid unnecessary bubbles in the syringe. Since insulin is being given under the skin, the presence of bubbles is not an enormous problem (as it would be with an intravenous injection) but we still want to minimize the presence of bubbles. If you get bubbles in the syringe, draw twice as much insulin into the syringe as you need. Then withdraw the needle from the insulin bottle and flick the syringe with your fingers until the bubble rises to the top and then simply push the air and excess insulin out of the syringe with the plunger back into the bottle.
- When this has been done, check that you have the correct amount of insulin in the syringe.
Injecting the insulin:
The steps to following for injecting insulin are:
- Hold the syringe in your dominant hand (right if you are right-handed or left if you are left-handed) with two fingers, like a dart.
- Have someone hold your dog while you pick up a fold of skin somewhere along your dog’s back or side using your free hand (pick a different spot each day).
- Quickly push the very sharp, very thin needle through your dog’s skin. This should be easy and painless. However, take care to push the needle through only one layer of skin and not into your finger or through two layers of skin.
- Reposition your hand with one finger on the plunger and inject the insulin. Push the plunger all the way into the syringe barrel.
- Before actually injecting your pet, practice drawing up the correct amount of insulin and feel comfortable handling the bottle and the syringes.
- Withdraw the needle from your dog’s skin. Immediately place the needle guard over the needle and discard the needle and syringe.
- To dispose of used syringes it is best to keep a thick plastic container (such as the type liquid laundry detergent comes in) and deposit used needles here. When the container is full, cap it and bring it to the veterinary clinic for proper disposal.
- Stroke your dog to reward it for sitting quietly.
It is neither necessary nor desirable to swab the skin with alcohol to “sterilize” it. There are four reasons:
- Due to the nature of the thick hair coat and the type of bacteria that live near the skin of dogs, brief swabbing with alcohol or any other antiseptic does not really kill all the bacteria.
- Because a small amount of alcohol can be carried through the skin by the needle, it may actually carry bacteria with it into the skin.
- The sting caused by the alcohol can make your dog dislike the injections.
- If you have accidentally injected the insulin on the surface of the skin, you will not know it. If you do not use alcohol and the skin or hair is wet following an injection, the injection was not done properly.
Although the above procedures may at first seem complicated and somewhat overwhelming, they very quickly become second nature. Your dog will soon learn that once or twice each day it has to sit still for a few minutes. In most cases, a reward of stroking results in a fully cooperative dog that eventually may not even need to be held.
Feeding The Diabetic Pet
Regulation is achieved via a balance of diet, exercise, and insulin. Realizing that special diets are not always attractive to pets, there are some ideal foods which should at least be offered, ask your veterinarian what these may be.
The most up-to-date choice is a low carbohydrate high protein diet such as Hill’s M/D diet or Purina’s DCO diet. (Both these companies use initials to name their prescription foods.) These diets promote weight loss in obese diabetics and are available in both canned and dry formulations.
Prior to the development of the above relatively new diets, the recommendation was to feed high fiber prescription diets. These also discourage obesity and seem to somehow make insulin receptors more sensitive in the body. Hill’s R/D or W/D diets or any of the other prescription foods would fit this category, though R/D is by far the highest fiber diet available.
One should avoid soft-moist non-prescription diets as sugars are used to preserve them. Breads and sweet treats should be avoided. If it is not possible to change the pet’s diet, then regulation will just have to be worked out around whatever the pet will eat.
It is necessary that your dog’s progress be checked on a regular basis. Monitoring is a joint project on which owners and veterinarians must work together.
The FIRST METHOD of home monitoring is to observe your dog for signs of diabetes. To do this, you need to be constantly aware of your dog’s appetite, weight, water consumption, and urine output. You should be feeding a constant amount of food each day, which will allow you to be aware of days that your dog does not eat at all or if it is unusually hungry after the feeding. You should weight your dog at least twice monthly. It is best to use the same scales each time. A baby scale works well for this if you have a small dog. If you have a big dog, just stop in at the hospital and weight him or her on our scale.
If possible, you should develop a way to measure water consumption. The average 10 pound (4.5 kg) dog should drink no more than 7 ½ ounces (225ml) of water per 24 hours. Since this is highly variable from one dog to another, keeping a record of your dog’s water consumption for a few weeks will allow you to establish what is normal for your dog. Another way to measure water consumption is based on the number of times it drinks each day. When properly regulated, it should drink not more than four times per day. If this is exceeded, you should take steps to make an actual measurement.
Urine output can be more challenging to measure. One method is to count the number of seconds the dog squats and urinates and the number of times the dog squats to urinate. If there is any significant change than actual measurement of the amount of urine must be made either at home of by your veterinarian.
Any significant change in your dog’s food intake, weight, water intake, or urine output is an indicator that the diabetes is not well controlled. We should see the dog at that time for blood testing.
The SECOND METHOD of home monitoring is to determine the presence of glucose and ketones in the urine. If your dog is properly regulated, there should be only a trace of glucose present and no ketones present in the urine.
There are several ways to detect glucose and ketones in urine. You may purchase glucose/ketone test strips at any pharmacy. They are designed for use in humans with diabetes, but they will also work in the dog. Place the strip in a puddle of urine on the ground wait for 60 seconds and check for glucose and ketones. You can also place a shallow pan under the dog when it urinates and capture enough drops of urine to place on the stick and measure the glucose and ketones.
If ketones are detected, we should see your dog that day or the next day. If there is glucose present in large amounts the test should be repeated the next two days. If it is still present in large amounts each time, we should see your dog for a blood test.
Method for using urine glucose to adjust insulin.
- Adjustment of insulin needs at home, using urine glucose levels as a monitor: (using Glucose Diastix, and occasional Keto-Diastix to see if ketones are present) .
- Check urines at peak and minimum insulin effect: if on a 12 hour cycle, check urine at approximately 6 – 8 hours post insulin and at 12 hours post insulin, if on a 24 hour cycle, at approximately 8 hours post insulin and 24 hours post insulin.
TRACE glucose is the goal; since spillage into urine assures the blood glucose level is adequate (in the 140-200 range).
Always allow at least 2 – 3 doses at a new insulin dose before adjusting the dose again. (a NEGATIVE may need an immediate decreased dose).
DOG OR CAT
If test is 4+ (2%), increase dose by 4 units 2 units
3+ (1%) 3 units 1 unit
2+ (1/2%) 2 units ½ – 1 unit
1+ (1/4%) 1 unit no change
TRACE no change no change
NEGATIVE, decrease dose by 2 units 2 units
Expect insulin dose adjustment to be needed on a continuous basis when:
Changing the activity level
Monitoring of Blood Glucose:
Determining the level of glucose in the blood is the most accurate means of monitoring. This should be done about every 1 to 3 months (based on what your veterinarian recommends) if your dog seems well regulated. It should also be done at any time the clinical signs of diabetes are present or if ketones are is detected in the urine or large amounts of glucose in the urine for two consecutive days.
Timing is important when the blood glucose is determined. Since eating will elevate the blood sugar for several hours, it is best to test the blood at least 8 – 12 hours after eating.
When testing the blood we may want to know the highest and lowest glucose readings for the day. The highest reading should occur just before an injection of insulin is given. The lowest should occur at the time of peak insulin effect. This is usually 5 – 8 hours after an insulin injection, but it should have been determined during the initial regulation process. Therefore, the proper procedure is as follows:
- Do not feed your dog its normal morning meal in the morning. Bring it to hospital just before the morning meal (around 8 am). Do not give your dog its morning insulin.
- A blood sample will be taken immediately and the highest glucose level determined. If we will be keeping your dog to get the lowest glucose level, we will admit him or her and after obtaining the first blood sample we will give insulin and feed your dog.
- A second blood sample will be taken at the time of peak insulin effect.
If your dog gets excited or very nervous when riding in the car or being in the hospital the glucose readings will be falsely elevated. If this occurs, it is best to admit your dog to the hospital the morning (or afternoon) before testing so it can settle down for testing the next day. Otherwise, the tests give us limited information.
Optional Other Materials
Keto-Diastix are special urine dipsticks made for human diabetics. They are meant to measure the amount of glucose in the urine and detect the presence of ketones. You may use these to keep track of your pet’s diabetic progress (a journal is a handy record for your vet to periodically review). If you begin to detect ketones in the urine, this can be a very bad sign. If ketones persist 3 days or more, you should notify your vet.
Hypoglycemia means low blood sugar. If it is below 40mg/dl, it can be life threatening. Hypoglycemia occurs under three conditions.
- If the insulin dose is too high. Although most dogs will require the same dose of insulin for long periods of time, it is possible for the dog’s insulin requirements to change. However, the most common causes for change are a reduction in food intake and an increase in exercise or activity. The reason for feeding before the insulin injection is so you can know when the appetite changes. If your dog does not eat, do not miss a dose of insulin unless the anorexia lasts for more than 48 hours. Always remember that it is better for the blood sugar to be too high than too low.
- If too much insulin is given. This can occur because the insulin was not properly measured in the syringe or because two doses were given. You may forget that you gave it and repeat it, or two people in the family may each give a dose. A chart to record insulin administration will help to prevent the dog being treated twice.
The mostly likely time that a dog will become hypoglycemic is the time of peak insulin effect (5 – 8 hours after an insulin injection). When the blood glucose is only mildly low, the dog will be very tired and unresponsive. You may call it and get no response. Within a few hours, the blood glucose will rise, and your dog will return to normal. Since many dogs sleep a lot during the day, this important sign is easily missed. Watch for it; it is the first sign of impending problems. If you see it, please bring in your dog for blood testing.
If your dog is slow to recover from the period of lethargy, you should give it corn syrup (1 to 2 tablespoon by mouth) or feed one packet of a semi-moist dog food. If there is no response in 15 minutes, repeat the corn syrup or the semi-moist food. If there is still no response, contact us immediately for further instructions. (Note: Diabetic dogs should not be fed semi-most foods except for this situation.)
If severe hypoglycemia occurs, a dog will have seizures or lose consciousness. This is an emergency that can only be reversed with intravenous administration of glucose. If it occurs during office hours, come in immediately. If it occurs at night or on the weekend, call our emergency phone number for instructions. It may be necessary to send you to one of the emergency centers for constant monitoring.
SUMMARY OF INSTRUCTIONS FOR DOGS RECEIVING INSULIN INJECTIONS
- Read and reread this material so that you understand the specifics of proper regulation and how to recognize and treat hypoglycemia.
- Give _____units of insulin at about __________AM and __________PM.
- Return for a glucose recheck in about one week. The recheck needs to be at or near the time your dog is due to get an injection of insulin. Do not make any changes in the feeding routine. Do not give insulin, but bring it with you.
- Feed your dog one of the foods recommended by the veterinarian in the amounts that is recommended by the veterinarian. Feed dry food and canned food every 12 hours. Give the canned food after the insulin injection so your dog sees the canned food as a reward for taking its injection. After a few days, your dog will “tell” you when it is time for insulin by begging for its canned food.
- Ettinger & Fieldman, et al “Veterinary Internal Medicine, 6th ed.,
- Schaer, Michael “Internal Medicine”, DC Academy Veterinary Medicine Proceedings, April 2003
- Tilley, Smith, et al “The 5 Minute Veterinary Consultant”, Lippincott, Williams & Wilkins Pub., 3rd ed., 2004
- Articles from websites:
- Veterinary Partners – (veterinarypartners.com) -articles on Diabetes Mellitus
- Veterinary Information Network – discussions and articles on Diabetes Mellitus