You Should Know when Your Dog Has Diabetes
Ron Hines DVM PhD............................................Might A Diet Change Be In Order ?
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Some Information About Your Dog’s Pancreas
Your dog’s pancreas is a small, light-pinkish organ that is nestled in the folds of its small intestine. It is not very striking – one might mistake it for ordinary abdominal fat. You can see it if you enlarge the fanciful image I put at the top of this page. Although it is quite small, the pancreas has two very important functions. One is to produce enzymes that allow your pet to digest food. The other is to produce a hormone (insulin) that regulates how your dog’s body utilizes sugar (glucose). Glucose is the main fuel of all animal cells. Most of the body’s glucose manufactured in the pet’s liver or released from recent carbohydrate meals.
The process by which the pancreas regulates your dog’s blood sugar level is actually much more complicated than my explanation and not yet fully understood. But my explanation should do for this article. Should you wish to know more, go here.
Many types of cells form the pet’s pancreas. The ones that are important in understanding diabetes occur in small islands scattered throughout the pancreas (islets of Langerhans). These particular insulin-secreting cells are called ß (beta) cells.
What Is Diabetes ?
There are pitfalls in trying to make the diabetes we see in dogs conform to the terminology invented to describe diabetes in humans or in assuming that the causes and treatments for the two should be the same. In some ways, diabetes in dogs and humans are similar. But in many ways they are not.
Several forms of diabetes occur in dogs; but the one affecting your dog is most likely Diabetes Mellitus (aka sugar diabetes). Pets with diabetes mellitus all have problems utilizing the sugar in their blood stream - either because their pancreas no longer produces enough insulin (similar to Human Type I Diabetes) or because the insulin is not as effective as it once was (similar to Human Type II Diabetes). There is little or no evidence that Type II diabetes occurs in dogs.
Most dogs that develop diabetes mellitus develop a condition similar to Type I diabetes of humans. (aka insulin deficiency diabetes = IDD) That is, for one reason or another, their pancreas no longer produces enough insulin. Because the problem is more common in certain breeds, veterinarians suspect that genetic (gene) factors are involved. There is also speculation that autoimmune inflammation may play a role in some cases diabetes in dogs. (ref)
Many veterinarians believe that the pancreatic beta cells in diabetes dogs have all been destroyed so no improvement in their health can occur without an external source of insulin. However, we do not know that with certainty. (ref) We identify them only through their insulin signature. They could still be there in some quiescent state.
Diabetes mellitus in dogs usually occurs between 5 and 12 years of age. It is quite uncommon to see it in pets under 3. Considerably more female pets (about 72%) , (ref) develop the disease than males and certain breeds seem predisposed to diabetes. They include the Samoyed, schnauzers, keeshond, puli, poodles, beagles, Tibetan terrier, dachshunds, schnauzers and Cairn terrier, while others such as the Boxers, Golden Retrievers and German Shepherd Dog seem less susceptible. (ref)
Most cats develop a condition similar to human Type II diabetes. Those cats still produce some insulin, but it is no longer as effective as it should be. What occurs in cats with diabetes is quite different from the treatment of dogs with diabetes. (ref) If you want to read more about the problem in cats, go here.
When your dog can no longer utilize its blood glucose to fuel its cells, a number of things happen. Your pet’s blood sugar level skyrockets up (hyperglycemia), some of the excess sugar spills out into your pet’s urine (glycosuria) , and its metabolism shifts to alternative sources of energy (it metabolizes fats and protein) to fuel its body.
Dogs do occasionally develop other forms of diabetes than Type l. A rare condition called diabetes Insipidus occasionally occurs in dogs, as does a temporary form related to pregnancy (gestational diabetes). Classical Type II diabetes in which insulin remains present in the body but is no longer effective is the most common type of diabetes in humans. There is littler or no evidence that this form of diabetes occurs in dogs.
The veterinary community in the USA is accustomed to thinking about blood glucose levels in your dog in milligrams per hundred milliliters of blood. The rest of the World is accustomed to thinking about blood glucose levels in millimoles per liter of blood. If you wish to convert one unit of measure to the other, go here.
What Caused My Dog To Develop Diabetes ?
It is usually unclear why one pet develops diabetes and another does not. It is likely that many factors are involved and that most of them were beyond your immediate control. Recent veterinary literature is full of studies that propose one cause or another – but there is little solid evidence to prefer one explanation over another. You can read the Waltham review on the subject here.
Developing Type I diabetes means loosing functioning beta cells. When this happens in dogs, it tends to occur gradually and gradual loss of cells of any kind is often due to chronic inflammation. The fact that it takes 80% of dogs 5-7 years for this destruction to occur also hints at chronic pancreatic inflammation as an underlying cause of the problem. (ref)
Here are a few ideas about why this might be occurring:
Auto-antiboides and Autoimmune Disease
Autoantibodies are defensive chemicals that the body mistakenly produces against its own tissue (in this case, its own pancreatic beta cells) or the compounds those tissues produce (proinsulin). There is some evidence that this might be occurring in some dogs similar to its known occurrence in humans. (ref1, ref2)
Chronic Or Reoccurring Inflammation Of The Pancreas – Pancreatitis
Some studies report that almost a third of dogs that develop diabetes have chronic pancreatitis. Only a small portion of its pancreas is devoted to insulin production. The much larger portion produces enzymes needed to digest food. When that portion of the dog's pancreas becomes inflamed, these highly corrosive enzymes leak into the surrounding tissue. The pet's beta cells can be a casualty of this inflammation. (ref)
Your Dog’s Breed And Genetics
It is apparent that certain breeds see more diabetes than others and that certain family lines within breeds are even more prone to it. That means that some combination of genes must promote the disease. Genes often work in tandem with environmental and other factors that one does have control over. So the fact that your pet carries increases susceptibility to a disease does not necessarily mean it will develop that disease. Here are some articles on the subject if you wish to read them: (ref1, ref2, ref3 , ref4) I wrote this article in 2011. It is now 2015. There have been great advances in dog genetics since I wrote it. The most recent study (a quite limited one) did not find genes that increased some pet's susceptibility to diabetes; but it did suggest that some genes might protect against it. (ref) If CRISPR technology has the potential it appears to have in 2015, there might come a day when we could edit defective genes when they were discovered. (ref)
High Fat Diets And Obesity
Although the positive connection between diet ingredients, obesity and diabetes is clearer in humans and cats, it appears to apply to some dogs as well. Fat reduces the effectiveness of insulin. Compounds called adipokines and leptins are involved in this process. You can read more about them in these references: (ref1, ref2 , ref3, ref4 ,ref5)
Pregnancy increases the risk of diabetes. Usually, the diabetes subsides after pregnancy ends but occasionally it does not. We think that the increased risk is due to high levels of progesterone that occur during pregnancy, and in non-pregnant dogs for the two months succeeding their heat period. Females that develop gestational diabetes tend to be middle-aged and in the latter part of their pregnancy. Certain breeds, including elkhounds and spitz, seem more prone to this problem. (ref1, ref2)
What About Environmental Factors ?
Rumors about that feeding, or not feeding, your dog this or that causes or cures diabetes. I do not know of any scientific proof that that is true.
There are certain chemicals that find their way into your pets body that are of concern to me. One is bisphenol A , a component of dog food can-lining coatings. This, and similar compounds are known as estrogen mimickers and endocrine disruptors. They have been proposed as being associated with diabetes and heart disease (ref), as well as hyperthyroidism in cats. (ref)
(During our lifetime, endodrine gland disease has been rising in pets and humans and we are always looking for reasons which might explain that.)
Sudden Pancreatic Atrophy
Immature keeshonds and golden retrievers occasionally develop sudden diabetes. More recently, a number of greyhounds developed a similar problem. The syndrome develops so suddenly that it has much bearing on the diabetes we see in older pets. You can read a recent article about the problem here.
What Signs I Will See When My Dog Has Diabetes ?
The physical signs you and your veterinarian will see are never specific
to diabetes only. Many medical conditions have similar signs. The
only way to be sure that a pet is diabetic is to document that its
blood glucose level is persistently elevated or that sugar is persistently
present in its urine.
Why Does This Increased Drinking And Urination Occur ?
The simplest answer is that water follows sugar. As your pet’s blood sugar level rises abnormally, osmosis draws more body tissue water (interstitial fluid) into its blood, increasing its volume. As that blood passes through the pet’s kidneys much of the blood’s water content enters its filtering elements (nephrons). Normally that water would be reabsorbed. But in the presence of elevated sugar, osmosis prevents its re-entry and excessive urine is produced. That lost urine water accounts for the pet’s thirst. (Water balance and kidney function are considerable more complex than my simplified explanation. If you would like to read a detailed explanation, go here.)
When dogs have diabetes for an extended period, they usually loose weight. This often occurs even when their appetite appears normal or even increased (polyphagia). By the time these pets become underweight, they have usually lost their normal energy level and sleep more as well.
These dogs are in a state of malnutrition. They often have elevated blood ketone levels as their body metabolism shifts from the glucose that is no longer available to them and draws on stored proteins and fats for energy. A few ketones are always present, but at high levels (ketoacidosis), they are toxic. Their appetite drops, they may refuse water; they may vomit. As a result these dogs become dehydrated. If this is allowed to continue, their body temperature will become sub-normal and they will progress into a coma.
The speed with which dogs decline is variable. Some maintain themselves
long enough to develop cataracts. In that state, they often have enlarged
livers, abnormal Liver
enzymes and an increased susceptibility to
Since this is a disease of middle and old age, other body systems can be abnormal in ways unrelated to the diabetes. So it can take your vet some time to sort things out.
How Will My Veterinarian Confirm That My Pet Has Diabetes – What Tests And Examinations Will My Vet Perform ?
After you have told your veterinarian the symptoms your dog is experiencing, your vet will do a complete physical examination. With that background, and particularly with the clues of increased thirst and urination, the vet will almost certainly run some blood tests (CBC+blood chemistries) and an examination of a sample of your pet’s urine (urinalysis).
Normal blood glucose levels in your pet’s blood are approximately 80 - 150 milligrams of glucose per deciliter of blood. (mg/dL) and urine should contain no glucose. In diabetic dogs, blood glucose levels can reach 300+ mg/dl (hyperglycemia). In those dogs, glucose is usually also present in the pet’s urine (glucosuria). In serious or advanced cases, it is common for the pet’s Liver enzymes to be elevated and for electrolyte imbalances to be present as well. Ketone levels in blood and urine are often elevated as well.
Your veterinarian may suggest other tests; depending on his/her suspicions. Occasionally over-active adrenal glands cause high blood sugar, so the vet might order tests like a urine cortisol/creatinine assay or tests that detect other pancreatic problems (cPL test). If your pet’s blood glucose is only moderately above normal, the vet may suggest a fructosamine assay or glycosylated hemoglobin assay that indirectly measure average blood glucose levels over longer periods of time.
Fructosamine tests are quite helpful in diagnosing marginal cases of diabetes and extremely helpful in determining effective insulin doses and treatment plans. With this test, your veterinarian can tell you how well your pet’s blood glucose level has been controlled over the last few weeks. In locations outside of the USA, other tests provide the same information just as well (hemoglobin A1c, glycated hemoglobin, glycated albumin) (ref) . There are a few rare conditions that can lead to false fructosamine test results. (ref)
Your Pet’s Treatment Plan
Your pet’s treatment centers around you providing your pet with the insulin its pancreas can no longer produce.
Additional things, like daily exercise, diet modification and weight loss for chubby dogs are important too. But managing its blood sugar level with insulin is the critical factor. In doing so, you will try to keep its blood glucose level as close to normal as possible without ever dropping to dangerously low levels (hypoglycemia).
A diagnosis of diabetes in your dog insures that you and your veterinarian
must form a close working relationship. Diabetes will be a lifelong
challenge for your dog and for you to be successful in dealing with
it, you must find a veterinarian whom you trust and whose personal
philosophy and practice style matches yours. (I
have an article on choosing the right veterinarian. You can read it
Do not assume that because your dog appears stable, that it does not need continuing checkups. Currently, the safest and most important test to monitor your diabetic pet’s health over time are periodic blood fructosamine assays (ref) performed twice a year in dogs that appear well regulated; more frequently if they don’t. If you cannot afford all these tests, you will need to be very scrupulous and frequent in the use of your glucometer.
Will Treating My Dog Take A Lot Of Time And Commitment On My Part ?
Not every dog owner can, or wants, to take on this responsibility. Yet many owners derive great satisfaction and personal growth from the experience. Dog owners may find that caring for their diabetic pet produces an intense bond and personal satisfaction that they had never, until then, experienced. (ref)
The decision needs to be a family decision because it will affect every member of your family, your spouse, your children, your co-workers, your other pets. Not only will you have to decide if you will treat your dog. You will have to decide on the level of treatment. These are things that veterinarians are not taught in school to help you with. Some intuitively understand it; others do not.
The most worrisome factors for some owners are the difficulty of finding pet-sitters and boarding facilities when you travel, some loss of control in your life due to the added responsibility, more difficult interacting with family and friends, more worry, less time for social life, added costs and interference with your work life. (ref)
Probably the least important fact for you to worry about is your ability to perform the procedures that will be involved. None of these procedures are that difficult to master and there are plenty of dog owners and veterinary staff willing to instruct you. If you live in an isolated area, the Internet is full of instructional videos.
"No Man Is An Island" (Donne). People do not thrive in isolation, particularly when they are confronted by illness in those they love. So go find your support network – the people that care about you and your pet. The Web will lead you to many support sites, your veterinarian can tell you of other dog owners facing the same situation with their pet.
Try not to be motivated by guilty feeling that you were in some way responsible for your pet’s diabetes. Dr. Vicki Rackner wrote an excellent article on caregiver support. You can read it here or visit her through this link.
There are no referees or policemen on the Web. As you educate yourself on the Internet, you will read many conflicting opinions as to what you should or should not do for your pet. You will see advertisements of miraculous diabetes cures and owners who swear that this or that cured their dog. You will find veterinarians hyping mystical procedures and extracts of rare plants that only grow in isolated valleys of the Himalayas, etc.
I know how much you love this dog and how much you want this problem to go away. But please, do not believe the claims of folks trying to sell you this stuff. Get your advice from people who do not wish to sell you anything. If you cannot find a reference to a product or procedure in the ncbi index, it will probably be of no value to your pet.
A group of veterinarians at the Royal Veterinary College of London wrote a good article on the challenges faced by the owners of diabetic cats. Most of it applies to dogs as well. Here it is in its entirety.
Most diabetic pets will need an insulin injection twice a day, coinciding with their morning and evening meals. Although some dogs appear to stabilize their blood glucose in the safe range with a single daily injection, I encourage twice-a-day injections if at all possible.
Feed the pet before its injections. If it does not eat or eats less than its usual amount, it will need a smaller dose or none at all. If it misses more than an occasional meal, consult your veterinarian. Giving pets their insulin injection when they have not eaten normally greatly increases the changes of hypoglycemia.
Your dog’s pancreas used to constantly monitor its blood glucose level and produce insulin accordingly – somewhat like cruse control feeds just the amount of gasoline your car requires to maintain a steady speed. You could obtain the same average speed pumping the gas pedal occasionally, but the ride would be jerky. I think the same principal applies to your pet.
What Dose Of Insulin Will My Pet Need ?
That decision will be made by your veterinarian. Most veterinarians will strive for an insulin dose that keeps your pet’s blood glucose level between 80 and 250mg/dl. There is no simple formula because some dogs continue to make a small amount of insulin on their own, because each dog absorbs and metabolizes insulin in its own special way, and because various brands and formulations of insulin each affect your dog differently. (ref)
Determining the best insulin dose for your pet takes several weeks (or months) and many adjustments. Do not be surprised if you dog’s insulin dose requirements vary over time.
Dogs just beginning diabetes therapy in particular, need their blood glucose level checked with a glucometer just before and 1 hour after their injection as well as at mid day. Testing their urine for sugar is not sufficient because it is low blood sugar that is most dangerous.
Some owners attempt to maintain their pets with a single daily dose of insulin. I do not recommend that. "All-day" insulins just don't seem to last all day in dogs. Your pet is better off if you give smaller doses of the insulin twice a day - determining the best dose and interval by plotting a glucose curve. I know that is a lot more work for you. But it is more likely to keep your dog’s blood glucose level as stable as possible throughout the day. (ref)
Determining Your Dog’s Proper Insulin Injection Schedule
The only safe way to develop an effective plan is by using your glucometer and preparing an insulin curve. Like proper dose, proper injection times vary with each individual dog. It is very important that you establish a standard routine of when you feed your dog and when you give it its injections and not vary from day to day. When and how much exercise your dog gets will also affect its blood glucose level. So try to keep day-to-day exercise activities on an even plane. To succeed in keeping your dog well “regulated” over time relies on three things proper dose, diet and exercise that do not change from day to day.
As Important As The Insulin You Give , Is How You Give It
The biggest pitfall in administering insulin is inadvertently giving too much, due to distractions, a new formula or bottle size, or incorrect syringe size. Your veterinarian or his/her technician will demonstrate how and where the injections should be given.
Do not attempt to use syringes designed for one insulin product with a different insulin product until you are absolutely certain the gradations (numbers) on the syringes are accurate for the product. If you are in doubt, have a pharmacist (not a pharmacy technician) confirm that the syringe and the insulin product are compatible.
Many communities regulate how used syringes can be disposed of. If this is a potential problem, call your local sanitation department and ask what is allowed in your area.
How To Give The Insulin Injection
Insulin injections are always given under the skin (subcutaneously). To either side of the pet’s spine, is a convenient location. Alternate sides and exact locations to minimize pain.
Insulin Injection Pens
Some dog owners find pre-loaded insulin pens that deliver a rapid, measured amount of insulin more convenient. It is a more expensive option than syringe and needle, but for owners or pets who dislike injections for one reason or another, it is a convenient option.
The pens are not very accurate with the very small doses required by very small pets. Talk to your veterinarian to see if this is an option for you and your pet. I still prefer needles and syringes; I feel that I have more control in placing the injected liquid under the skin and not into the muscle. Intramuscular injections of insulin cause a much too rapid drop in blood glucose but a shorter period of effect.
What If The Calculated Dose Of Insulin Does Not Lower My Pet’s Blood Glucose Level Enough ?
Blood sugar level in some pets is harder to control than others. Some call this “insulin resistance”. But that is a confusing term because true “cellular insulin resistance” is a phenomenon that occurs in human Type II diabetes – not the form of diabetes common in dogs.
The first thing to do is to be sure you are really giving the amount of insulin suggested by your veterinarian. The biggest cause of unexpected or poor results is giving the insulin product incorrectly.
Be sure your bottle of insulin is not expired and that it has been properly stored (most formulations must not be frozen). The next thing to do is to verify that your glucometer is accurate and that you are making your glucose level determinations correctly. The best way to do this is to check your dog’s blood sugar level on two different meters. Blood glucose levels are constantly changing. You will need to do the two tests simultaneously or one right after the other.
If neither of the above problems are occurring, your veterinarian will probably increase or lower your dog’s insulin dose. Generally, veterinarians begin pets on a low or moderate dose of insulin. That leaves room to adjust the dose upward if need be.
If changing your dog’s insulin dose still does not solve the
problem, your veterinarian may try your pet on another brand or formulation
Here are other factors that sometimes cause this problem:
Overly plump dogs and dogs eating high fat, greasy diets sometimes have problems utilizing injectable insulin. (ref)
Some dogs are known to produce antibodies against certain insulin formulations that prevent their proper action. This seems to be a particular problem when cow pancreas, rather than pig pancreas, was the source of the insulin. (ref)
Pets that are receiving corticosteroids for other health problems may appear to be resistant to their insulin injections. This is because corticosteroids raise blood glucose levels. Corticosteroid levels are also elevated in Cushing’s disease (hyperadrenocorticism). You vet may screen your pet for this condition when insulin appears less effective than it should be in lowering your pets blood glucose level.
As I mentioned earlier, If your pet is an un-spayed female, high progesterone levels that accompany and follow her heat periods can affect her blood glucose level and can make insulin doses less effective.
Occasionally, what appears to be an ineffective insulin dose is really due to receiving too large a dose of insulin. This is called rebound hyperglycemia (Somogyi Overswing effect). When it occurs, the dog’s blood sugar level drops drastically and rapidly after receiving too large a dose of insulin. But the dog’s body quickly releases its own cortisone and adrenalin that cause its blood sugar to soon rise to abnormally high levels again. Careful examination of your pet’s blood glucose curve will detect this phenomenon. The treatment is smaller and possibly longer acting insulin doses.
Checking Your Dog’s Blood Glucose Level At Home
Keeping a close watch on your pet’s blood sugar level at home is the key to keeping it healthy. The best way to do this is for you to purchase and learn to use a hand held glucometer.
Obtain the small blood samples by pricking its skin with commercial lancets. You will find, through experience, which sites bother your pet the least. The pet’s upper and lower lips, (near the base of the jaw) generally works well. So do the calluses to the side and rear of their elbows and their metacarpal foot pads (the one on the rear of the front leg that does not touch the ground) The base of the tail works well, if you first shave the area. Generally, the least painful areas are contact points with the floor when the pet is at rest. Although many owners prick their dog’s ears, I find them more sensitive than these other locations.
Most dogs accept this procedure readily. Those that don’t will have to rely on periodic glucose testing at their veterinarian’s office, the services of a house-call veterinarian or periodic blood fructosamine tests.
Checking for the presence of glucose in your pet’s urine is not sufficient. Sugar does not enter your pet’s urine until its blood sugar level is quite high and it may only appear intermittently. But I suppose urine test strip testing is better test than no testing at all.
More dog owners use human glucometers to test their pets than the
meters designed specifically for animals. This is primarily due to
the difference in cost.
What should concern you more than the price of the unit is the price of the test strips. Over time, the strips represent most of your true cost. When you calculate the cost of online supplies, be sure the strips that are offered have a long enough expiration date for you to finish using them. Cheap strips are often short-dated.
No matter what brand you buy, check your unit and your strips periodically against the one used by your veterinarian or a trusted friend, as well against the your test solutions. Remember that blood serum and plasma glucose levels run at a lab are often 10-15% higher than results obtained on meters.
The most important facts to look for in a meter are accuracy and repeatability of results, and a very small amount of required blood sample – particularly if your dog is small. Another important feature is that the test strips be very absorbent in drawing up blood from your test prick site (“sipping”). Unless you are uploading your dog’s results to a graph on your computer, additional features, that are added to many meters, are really an unnecessary complication and expense.
The most popular human glucometer used on pets is probably the FreeStyle Freedom unit made by Abbott. It requires the smallest blood sample (0.3 microliters). If you intend to rely on your meter to also check for ketones, the Precision Xtra from Abbott will do that.
There is debate as to whether glucometers designed for pets are any more accurate than using the ones designed for humans. But there is no debating that pet-designed units are considerably more expensive. (ref)
Be aware that meters marketed to the US give their glucose reading in milligrams/deciliter (mg/dL). In the rest of the World, the meters usually display in millimoles/liter (mmol/L). There are websites that will do automatic conversions.
Factors That Affect Your Meter Reading
Pets that are anemic may appear to have higher blood glucose levels than they really have. If your dog is not consuming enough water or if it is dehydrated, it may also test higher. Testing after your pet eats a fatty meal can also influence the meter reading as can vitamin C supplements.
Other things that commonly cause inaccurate readings are low batteries, expired test strips, insufficient or too much blood on the strip, dirty meters and failure to regularly check your meter’s calibration against the test solutions.
Preparing A Glucose Curve Chart For Your Dog
Persistently high glucose levels damage your dog’s health over time. Occasional spikes are not that important, what is important is that your treatment plan keeps glucose at as close to normal as possible over the majority of time.
Plotting these curves will let you do that. It is the only intelligent way to adjust your pets insulin dosage. It will tell you the highest and lowest blood glucose reading of the day, how long it takes the injection to affect the pet and the length of time the insulin remains effective.
You will use the graph results to adjust your pet’s not only to adjust its dose, but also to choose the best insulin type for your pet, best injection interval, best diet, exercise plan and lifestyle in a way that keeps its blood glucose level as stable and close to normal as possible with the fewest dramatic peaks and valleys (nadirs). That was the job of your dog’s pancreas. It is your job now.
Recommendations vary as to how to prepare glucose curve charts. I prefer clients prepare the curve at home, although it can also be done at the animal hospital. I tell clients to obtain their first glucose reading one hour prior to their dog’s morning insulin injection, one hour after the injection and then every hour until the reading has reached its lowest point and begun to rise again. From then on, the sampling can be done every two hours.
You can read an extensive explanation of glucose curves published in the Clinician’s Brief Here
You should always allow your pet to become accustomed to a particular insulin dose and treatment plan for a few days before attempting to prepare a full glucose curve.
You should also be aware that the test has limitations - it is hard to get reproducible curves on consecutive days, and that there is considerable day-to-day variability.
Sometimes the curve you obtain will not mesh with your dog’s clinical picture. Occasionally, the curve may show that the pet’s glucose is under good control when it isn’t. If your dog is continuing to drink and urinate excessively, experiences periods of weakness, or fails to normalize its weight, go with your intuition that something is wrong and call your veterinarian.
I prepare graphs similar to the one in my illustration using Graph 4.3. You can also use the Vetsulin insulin curve generator.
Adjusting Your Dog’s Insulin Dose Based On Its Insulin Curve
For these graphs to be accurate, they are best prepared at home. At an animal hospital, your pets eating habits, ability to exercise and stress level will be quite different than at home. That will often affect the results.
There is no one firm rule as to what your dog’s “normal” blood sugar level should be because it is constantly fluctuating. But a value that I often used is about 75 – 175mg/dL [4.2-9.7mmol/L] , with the average being around 80mg/dL [4.4mmol/L].
Don’t attempt to maintain your dog at or below 100mg/dL. That would leave too little down space between what is normal and what might lead to hypoglycemic shock. Instead, consider an 100mg/dL – 185mg/dL [5.5-10.3mmol/L] average or so as your ideal goal. Some owners of easy-to-regulate pets succeed in keeping their average blood sugar level lower. But it is not something you should attempt until you are thoroughly comfortable with how your pet responds to its injections. Do not become frustrated if you cannot maintain an ideal blood glucose level in your pet. Many owners must be content with higher peak levels.
If your dog’s blood sugar reading reach peaks over 180 - 270 mg/dL [10-15mmol/L], sugar will begin to appear in its urine.
Dogs with persistent readings over 250mg/dL [16.6mmol/L] are at risk of developing health complications. These pets often have ketone-positive urine.
When contemplating your pet’s insulin curve, look for trends – not specific points.
BE VERY CAUTIOUS WHEN YOU ATTEMPT TO CHANGE YOUR DOG’S INSULIN DOSE. ALWAYS DO SO IN CONSULTATION WITH YOUR VETERINARIAN. GIVE NON-HYPOGLYCEMIC DOGS AT LEAST FOUR DAYS BEFORE DECIDING THE TRUE EFFECT OF THE CHANGE AND BEFORE ATTEMPTING ANOTHER CHANGE.
Many pet owners follow the ten percent rule – never changing their dog’s insulin dose by more than 10% in 4 days.
Every pet is different. A few require more than the typical twice-a-day injection procedure.
dose and frequency adjustment is more of an art than a science. There
is quite a bit of variation in blood glucose from day to day in the
same pet. That is
Repeat your curves every 3-6 months – more frequently if you are having glucose control issues.
Most veterinarians believe that that the flatter your pet’s glucose curve remains - with the least dramatic peaks and valleys- the less likely that diabetes-related health problems will occur.
What If My Dog Is Not Eating ?
When your pet is not eating, its insulin needs are lower. It is also more likely that its blood sugar level will drop to dangerously low levels if you give it its usual dose. Sometimes, fairly minor things like excitement, stress, indigestion or human family emergencies prevent your pet from eating on schedule. In those instances, be cautious and give the pet less insulin than you normally do. Remember, a day of high blood sugar is not nearly as serious as an hour of dangerously low blood sugar.
My Neighbor, Cynthia, Does Just Fine Taking Oral Meds To Control Her Diabetes, Why Can’t My Vet Give My Dog Those Pills ?
It would be wonderful if there were oral anti-diabetic medications that were effective in dogs – but as of now, we have none that work. Most diabetes in humans is adult onset diabetes aka Type II diabetes. In that form of diabetes some insulin is still being produced - pancreatic beta cells just need extra stimulus to produce more of it and cells need extra assistance in absorbing glucose from the blood stream.
In dogs, most diabetes is Type I diabetes. In that form, the pet’s ability to make insulin just isn’t there (its beta cells are gone or non-functional) So insulin “booster” medications are not effective. There are many types of oral medications to help human diabetes. Some of them have other modes of action; but none of them seem to help dogs. (These oral drugs are, occasionally, helpful in cats but not dogs)
When your dogs blood sugar level is over about 180mg/dL some of the sugar leaks out into its urine. So many unregulated dogs have glucose+ urine. There are simple “dipsticks” that detect this and they are a common screening test for diabetes.
However the test is too crude to be used to monitor diabetic pets when you attempt to keep their blood glucose in a safe range. The test can lag behind blood glucose spikes and it will not detect dangerously low blood glucose levels. The dipsticks can be useful. They will detect persistent ketone in your pet’s urine – a sign of ketosis and they are better than nothing if your circumstances or your pets disposition prevent the use of glucometer.
Is Dietary Therapy In Addition To Insulin Important ?
Most veterinarians think it is. In Type II diabetes, the common form in humans , we know that feeding diets with added fiber, reduced fat , complex carbohydrates substituted for simple sugar are all helpful in regulating blood glucose levels.
We know that fatty diets, in addition to making your pet obese, reduce your dog’s ability to utilize insulin (ref) and it did initially appear that canine diets with added insoluble fiber (sugar beet pulp) help stabilize blood glucose levels in dogs. (ref1, ref2, ref3)But a more recent study published in 2009 did not find any advantages in feeding high-fiber, reduced carbohydrate diets to diabetic dogs and warned against their use in dogs with thin body condition. (ref)
So despite all the hype from prescription dog food manufacturers, that is all the legitimate science we have to back up their claims. You know how many people tell you what you should, or should not eat and it is no different with our pets. Basing ones conclusions on a compound (glucose) that bounces up and down due to multiple factors and doing it in only a few dogs, studied for short periods of time will probably never tell us anything we can count on. Here are my suggestions:
I usually suggest that clients feed their dogs a, nutritionally balanced, homemade diet whenever possible. But I understand that not all of us have that option or inclination. You can find some homemade diet suggestions here. Us humans do not usually rely on professional nutritionists to plan our meals, but if you are hesitant about the homemade foods you feed your dog, there are professionals that will review your plan ( link1 , link2 )
You must be cautious when feeding high fiber commercial or homemade diets to diabetic dogs that are underweight or experiencing health problems that affect their ability to metabolize food. Determine what the optimal weight for your pet is and weigh it frequently to be sure it is not becoming underweight.
Pay attention to the luster of its coat, flakiness of its skin and general energy level when on these diets. Some dogs do not like the taste or smell of commercial diets marketed for diabetic dogs. Try various brands. Never give ultimatums or force your dog to eat these diets. Try introducing them to the new foods very gradually. If they refuse to eat it, and they are currently on a nutritionally balanced, sensible diet, proper insulin administration and exercise will allow you to manage their diabetes problem quite will without it.
Regular Exercise Contributes To Success
Always begin exercise programs cautiously and slowly
You are unlikely to lower your pet’s weight through exercise alone. You will need to control what the dog eats and how much it eats as well. But exercise will certainly help achieving its ideal weight and exercise has great health benefits beyond weight reduction alone.
Simply reducing the food intake of plump dog’s will cause them
to be more active, alert and exploratory. Exercise also changes the
way cells react to insulin. (ref)
And, although not as great a risk factor as it is in humans or cats,
Can My Dog’s Diabetes Be Cured ?
The form of diabetes that affects your pet cannot be cured. But it can improve. It is common to assume that in Type I diabetes, your dog’s pancreatic beta cells are gone and once gone, they can never return.
That idea may not be entirely correct. A phenomenon called islet neogenesis is known to occur and research efforts are ongoing in dogs to try to encourage this process artificially (ref) or by relying on the dog's own pancreatic stem cells............ (ref1, ref2)
When your pets diabetes is the result of medications it received, pregnancy or Cushing’s disease other curative options do exist.
What Are Ketones And Why Are They So Important To Avoid ?
When your pet lacks insulin and can no longer fuel its body’s cells with blood sugar, it switches its metabolism to fuel those cells with the fatty acid portion of its stored body fat and portions of its own muscle protein.
This metabolic switchover leads to excess formation of ketone (ketone bodies). Some are always forming in your dog’s body. But when the process accelerates in pets starved for energy due to diabetes, or fasting from a lack of food or appetite, the excess ketone acidifies its blood to dangerous levels. This condition is called ketoacidosis (aka DKA or ketosis).
Signs of ketoacidosis can include, vomiting, diarrhea, weakness, dehydration and rapid shallow breathing. The body can only operate in a narrow range of acidity (pH). Blood glucose levels in these cats are usually sky high and ketones are present in the urine. Untreated, severe ketoacidosis can be rapidly fatal. (ref1, ref2)
When uncontrolled (unregulated) diabetic dogs are presented to veterinarians in this condition, they require immediate IV fluid administration to correct dehydration, rapidly acting, short-term insulin to bring high blood sugar levels down, often additional intravenous potassium, continuous monitoring and intensive care. Some pets become deficient in blood phosphorus as well and many require intravenous buffers (bicarbonate) to bring their blood pH back into normal range. Many of these dogs have other health problems (like Cushing’s Disease) that make the problem worse.
It is not unusual for veterinarians make their first acquaintance with a diabetic client during a ketoacidosis crisis. That is the first occasion that some pet owners realize that something is seriously wrong with their dog.
You can monitor your pet’s ketone levels at home. The procedure is simple. It only requires urine dipsticks (Ketostix) available online (Ebay) or at the pharmacy with no prescription. Check your pet’s first urine of the morning. Do not panic if it is occasionally weakly positive. If it remains so for two or more days in a row, consult your vet. Portable meters are also available to do this if your pet suffers recurrent attacks. (ref)
What Are Some Danger Signs ?
I Need To Watch For In My Pet ?
Diabetic pets have an increased risk for certain problems. If you know what these problems are, you are more likely to discover them early, when treatment is more successful. (I listed them roughly in the order of their importance and frequency.)
Hypoglycemia – abnormally low blood sugar
Blood sugar levels drop to dangerously low levels in diabetic dogs
when you give them too much insulin (less than
55mg/dL). That can be because their dose was too large
or because it was more than their current needs. Perhaps they did
not eat that morning, exercised more than usual or were under unusual
If their blood sugar level continues to drop, pets become sleepy, unresponsive and eventually loose consciousness. The speed with which this all occurs is unpredictable.
If your dog is still willing to eat, immediately offer it some of its normal diet. Check its blood glucose level with your glucometer. If its blood sugar reading is abnormally low, try to make a list of things in your mind that may have caused the problem and avoid them in the future. Call your veterinarian to discuss the problem and see if the pet needs to come in. If the problem appears serious, just put the pet in your car and take it in immediately.
Not all hypoglycemic dogs are capable of eating food. Never attempt
to make a seizuring or confused pet swallow food, or anything else.
They make choke.
You can ask your veterinarian for a syringe or container of 50% Dextrose (5% dextrose (D5W is too dilute). I make sure all my clients have some around – particularly when they are just beginning or changing insulin doses. You can also go to your pharmacy or Wal-Mart, purchase some glucose tablets (Dextrosol, B-D glucose tabs, etc.) and dissolve them in warm water. Wait 15 minutes and check the pet’s blood sugar level again. Repeat the dose if need be. Keep unused sugar solutions refrigerated.
Some folks suggest Karo Syrup or anything sweet. That is better than nothing, but not as effective. Products containing table sugar contain sucrose, not glucose (aka dextrose). Sucrose is 50% glucose and 50% fructose. Karo Syrup is a form of high fructose corn syrup. It contains more glucose than generic corn syrups, but it also contains other sugars (maltose, maltotriose, maltotetraose). Generic Corn syrup is 55% fructose and 42% glucose. Although you dog’s liver can metabolize the fructose into glucose, that takes more time (intermediate glycolysis in its liver). (ref)
The best way to give glucose solution to your pet is by wetting the lining of its lips, mouth and tongue with it. Some suggest smearing it under the tongue. Just be careful not to be bitten or use a toothbrush to “paint” it around the oral surface – dogs that are “spacy” from hypoglycemia do not know what they are doing and their jaw muscles often spasm. Do not pour or squirt liquid into the dog’s mouth - it is libel to go down wrong.
Small, periodic amounts of glucose are better than one large amount. Some folks say it can also be given through the other end with a rectal enema. Theoretically, that is possible. I have never tried it. I would prefer you just get a pet in that debilitated a condition to a veterinarian as rapidly as possible.
Many owners are hesitant about giving glucose to their pet – after all, they were under the impression that the whole point of diabetes treatment is to lower glucose sugar. Don’t worry about that in a hypoglycemic emergency. The short period of time your dog’s blood sugar level will be high will have no effect on its long-term health.
As soon as the pet is willing to eat, allow it to. Keep a close watch on it, that the problem does not return - the glucose you gave will have only a short time effect (sugar high) and may need to be repeated. As soon as it can eat its normal diet, it will get the more complex carbohydrates that supply sugar in a more steady stream.
After the incident has passed, sit down with your veterinarian to re-evaluate your pet’s insulin dose, interval and any other factors that might have caused this crisis and correct them. Remember that the glucose curve graph you made for your dog may not have caught blood glucose at its lowest point between blood-draws. If the curve was headed in a downward slope, it may have dipped even lower sometime before the next time you drew blood. That may have been the point when hypoglycemia occurred.
Ketosis (aka Ketoacidosis, DKA)
When your dog lacks insulin and can no longer fuel its body’s cells with blood sugar, it switches its metabolism to fuel those cells with the fatty acid portion of its stored body fat and portions of its own muscle protein. This metabolic switchover leads to excess formation of ketone (ketone bodies). Some are always formed in your pet’s body. But when the process accelerates in dogs that are starved for energy due to diabetes or fasting from a lack of food or appetite, the excess ketone acidifies its blood to dangerous levels. This condition is called ketoacidosis.
Signs of ketoacidosis include, vomiting, diarrhea, weakness, dehydration and rapid shallow breathing. The body can only operate in a narrow range of acidity (pH). Blood glucose levels in these pets are usually sky high and ketones are present in their urine. Untreated, severe ketoacidosis can be rapidly fatal. (ref) Pets whose blood sugar levels are poorly regulated are also prone to produce excess sorbitol. Besides playing a part in diabetic cataract formation, this sorbitol may contribute to ketoacidosis. (ref)
Dogs that arrive at veterinarians in this condition require immediate IV fluid administration to correct dehydration, rapidly acting, short-term insulin to bring high blood sugar levels down, often additional intravenous potassium, continuous monitoring and intensive care. Some will become deficient in blood phosphorus as well and many require intravenous buffers (bicarbonate) to bring their blood pH back into normal range.
It is quite common for veterinarians make their first acquaintance with a diabetic client during a ketoacidosis crisis. That is the first occasion that some owners realize that something is seriously wrong with their pet.
You can monitor your pet’s ketone levels at home. The procedure is simple. It only requires urine dipsticks (Ketostix) available online (Ebay) or at the pharmacy with no prescription. Check your dog’s first urine of the morning. Do not panic if it is occasionally weakly positive. If it remains so for three or more days in a row, consult your vet.
Increased Susceptibility To Infections
It is not clear that the elevated blood sugar levels of diabetes in themselves make your pet more susceptible to infections. encourage but the general debility (= unhealthy state) of poorly regulated diabetes makes such infections more common. (ref)
An exception is cystitis or kidney infection. The presence of sugar
in the urine of diabetic pets and humans make those problems more
Dogs that develop diabetes often also develop cataracts in the lenses of their eyes. When this problem is advance, your pet may be unable to see.
Cataracts are lenses that are no longer clear to the passage of light. There are many kinds of cataracts that affect dogs, the most common form, affecting all old dogs, is not a true cataract at all. In those old dogs, the fibers that compose the lens become tighter and more densely compressed together, reflecting a hazy cloudiness, referred to as lenticular (nuclear) sclerosis. Although lenticular sclerosis may look serious to you, the dog actually retains most or all of its vision and will not bump into objects or walk hesitantly.
When true cataracts such as diabetic cataracts occur, the dog’s lenses appear mottled or appear to be fractured like a broken chunk of ice. True cataracts can occur in one or both eyes. But normal nuclear sclerosis occurs simultaneously in both eyes to the same degree.
When true cataracts form in diabetic dogs, they form because of increased glucose levels in the eye. Your pet’s lenses are alive. Like all living tissue, they need nutrients. In their case, the nutrient is glucose. However, when glucose levels are too high, some is converted into another sugar, sorbitol, that has destructive consequences for the dog’s lens. (ref)
If your diabetic dog looses only its vision, it will remain happy and content because dogs interact with their environment more by scent than by vision. (Their sense of smell is hundreds of times more sensitive than yours)
There are veterinary ophthalmologists who can remove one or both of these cloudy lens and replace them with artificial ones. But that is not a surgery that I often recommend. It is expensive, complications are frequent and it subjects your pet to a lot of stress. I do suggest that pets with diabetic cataracts be seen by a veterinary ophthalmologist occasionally to confirm that pressure within the pet’s eyes remains normal and is not elevated (glaucoma) and that no inflammatory eye changes (uveitis) that need medication are present. Eyes that have cataracts are more subject to those sorts of problems. (ref) as well as to dry eye (keratoconjunctivitis sicca) (ref)
Adrenal Gland Problems - Cushing’s Disease
Another endocrine gland occasionally malfunctions in your pet. It is the adrenal gland. There are two of them, just ahead of each of your pet’s kidneys. One of their jobs is to produce cortisone. When these glands malfunction in dogs, they generally produce too much cortisone. One of the effects of cortisone is to raise your pets blood glucose levels. So it occasionally happens that a dog has both over-active adrenal glands (Cushing’s disease) and diabetes. This is not the diabetes of lost beta cells (Type I) so if the pet’s adrenal problem can be regulated, their diabetes may improve or disappear. (ref) You can read more about Cushing’s Disease (hyperadrenocorticism) here and how it interacts with diabetes here.
Severe Diabetic Dehydration__________________________ (aka Severe Hyperglycemia, Hyperosmolar Non- ketotic syndrome, HHNK, HHS)
When pets develop hy-po-glycemia, their blood sugar level has fallen below 60mg/dL.
However, on rare occasion the blood sugar levels in untreated or inadequately treated dogs will soar to extremely high levels – greater than 650mg/dL. In this extreme hy-per-glycemia, several things rapidly occur:
Blood with this amount of sugar has an extreme affinity for water. So water is sucked out of the brain and into the bloodstream. This results in severe depression and weakness. The pet stops drinking and eating and can rapidly become comatose. Water is not only lost from the brain, it is lost from the body through urine. So the dog becomes severely dehydrated as well (hypovolemic shock). There eyes become sunken and their gums are usually tacky or dry. Their skin looses its normal springiness and elasticity and remains “tented” when it is plucked upward.
This results in dehydration at the cellular level – fluids are
literally sucked out of the body cells and intracellular space by
the extremely high level of blood glucose. This is not ketosis so
the pet’s urine remains relatively ketone-free.
Elevated Blood Pressure
Dogs that are diabetic are at increased risk of developing elevated blood pressure (hypertension). (ref) High blood pressure can cause kidney damage in dogs. So it is wise for your vet’s periodic health checks to include a check of the dog’s systolic blood pressure. Should it be high, there are medications to lower it.
Nerve Problems Associated With Diabetes
Nerve problems do not seem to occur as frequently in diabetic dogs as they do in diabetic humans. But they do occur occasionally. (ref) The most commonly reported sign is weakness in the rear legs. There are many non-diabetic causes of rear leg weakness in older dogs. When things are unclear, nerve condition studies may be able to sort the problems out. (ref)
There is also some evidence that uncontrolled diabetes can effect the nerves that control heart rhythm (vagal neuropathy) (ref)
The Need For Caution When Giving Your Pet Other Medicines
Certain medications, particularly corticosteroids, interfere with the positive action of insulin. Diabetes can also alter the way your dog handles other drugs. The major organs where insulin is active are the liver, muscle and fat tissue. So any medications that affect those organs have the potential to affect diabetes control. Diuretics (thiazide diuretics), thyroid hormone supplements, anabolic steroids,niacin, melatonin, certain antibiotics (tetracyclines, erythromycin), certain heart medications (beta blockers) and aspirin , among others, may have the potential to affect the glucose dynamics of diabetic dogs.
If My Female Pet Is Not Neutered Will Neutering Help In Its Treatment ?
If an unneutered female dog’s blood sugar is hard to control, spaying it may help. Don’t rush out to spay your elderly dog just because it has developed diabetes. Wait and see how well standard insulin, diet and exercise control her blood glucose level. (Of course, do not allow the dog to become pregnant) Progesterone, the hormone of pregnancy is the hormone that interferes with glucose control. It is present in substantial amounts from the middle of the dog’s heat period and for about two months thereafter – regardless whether the dog is pregnant or not. If you have difficulty controlling your dog’s blood sugar level during that time, spaying the dog may help. If it is at other times in its cycle I doubt that it will.
Are New Treatment Options On The Horizon ?
Yes. There are some very interesting developments.
It is a curse and a blessing that dogs are used in human diabetes research.
Sophisticated glucose sensors have been successfully implanted in dogs. The next step in this research is to implant insulin pumps that administer insulin to these dogs in a more natural way, avoiding the peaks and valleys associated with twice-daily injections.(ref1 ref2, ref3)
Transplants of living pancreatic tissue into diabetics have not been very successful. This is because the implanted tissue usually does not survive unless very powerful anti-rejection drugs are continuously given. But there have been positive studies in dogs where this tissue was protected from rejection by surrounding it with a protective, artificial layer (microencapsulation). Perhaps this offers a future cure for diabetes. If it does, dogs will pioneer the effort. (ref1, ref2)
A few studies claim to have had encouraging results in attempting to regenerate pancreatic beta cells in dogs. But like all current body regeneration projects, it remains a distant dream. (ref1, ref2)