Dog News

Canine Diabetes Mellitus

by Shawn Finch, DVM

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Frankie the Cute

Your dog’s diagnosis of diabetes may bring up all sorts of emotional images.  You think of cats and dogs and other loved ones you have known with every type of diabetes.  You remember injections, mortality, complications…

Even if you have not dealt with diabetes in the past, the diagnosis is no less emotional.  If you have a fat dog, you may think, “I caused this!”  (You didn’t.)  If you have a skinny dog, you may think, “This is not fair!”  Truly, many medical conditions of our pets, including diabetes, seem unfair.  Our pets should never suffer, but life being what it is, our role is to minimize their suffering and enhance their lives as much as we can.

Frankie at the Surf Dog Festival1
Frankie Jarolim, living well with diabetes

The super cute dog in all of the pictures is Dr. Edie Jarolim’s Frankie Dog, who is living well with diabetes.  Visit Edie’s wonderful blog, Will My Dog Hate Me? where Frankie is often featured.

Edie made a great point when we were discussing canine diabetes:

“It’s never good for a pet to be obese, but lately veterinary anti-obesity campaigns have included diabetes as a reason for both dogs and cats to slim down.  That’s true for cats, but in the case of dogs, it’s inaccurate and I find it frustrating.  Canine diabetes is almost always akin to Type 1 — “juvenile” — diabetes in humans, except that the onset is usually in middle age or later.  The latest findings have concluded it’s almost certainly a genetic disease that even mixed breeds are subject to.  Why is that distinction important to me?  Because having a diabetic dog isn’t easy to deal with, though very manageable, and I hate to compound those difficulties with the sense that there’s something a dog owner could have done to prevent her pup from getting the disease.  And because I like my medical information to be accurate!”

Stupid Long Medical Words

Glucose  – the most important simple sugar used by the body for energy-requiring functions.  Blood sugar and blood glucose are used interchangeably when discussing diabetes.

Hyperglycemia – high blood sugar (hyper – high, glyco – sugar, emia – in the blood)

Hypoglycemia – low blood sugar (hypo – low, glyco – sugar, emia – in the blood)

(One of the reasons I LOVE stupid long medical words is that parts can be mixed and matched to make new words.  Well, not by me, but someone got to.  And once you know the parts, the big words make sense.)

Polyuria – excess urination

Polydipsia – excess thirst

PU/PD – abbreviation for polyuria/polydipsia, two conditions that almost always occur together.  PU/PD seems a bit “chicken and egg,” and it is indeed a cycle, but usually polyuria comes first, as a mechanism used by the body to try to right an imbalance.

Insulin – This is the hormone produced by the pancreas that regulates blood glucose.  I think of glucose and insulin as teeter tottering friends.  In situations where insulin and glucose are NOT acting like friends (like diabetes), it is a good picture to have in mind as we try to bring things back into balance.

A Boy and a Girl on a Teeter Totter - Royalty Free Clipart Picture

Glucose and Insulin Playing Together Nicely

Pancreas – an organ adjacent to the stomach and small intestine that, among other things, produces insulin.  Grossly, in every sense of the word, it resembles a giant, smashed earthworm.  Awesome.

Beta Cells – These are the cells of the pancreas that produce insulin.  If the immune system destroys these cells, insulin is not produced and diabetes mellitus results.

If the immune system has not destroyed the beta cells and they are continuing to produce insulin, but the body is not responding appropriately to the insulin and not able to utilize glucose appropriately, that too can result in hyperglycemia and diabetes mellitus.

Ketoacidosis – a potential complication of hyperglycemia and a medical emergency.  Excess blood sugar causes fat to break down inappropriately, resulting in ketone bodies.  Ketone bodies cause acidity, which can be fatal if unchecked.

Glucose Curve – serial measurements of blood glucose over a period of time, typically hourly or every other hour over twelve or twenty four hours.

Fructosamine –  Fructosamine is a protein that can be measured to estimate glucose control over several weeks.  Fructosamine is a measurement of averages and will not show bounces or extremes.  At one point, we hoped it could replace the more cumbersome glucose curves in diabetes management, but it has not.  It is still a helpful tool in monitoring diabetes though.

Diabetes – In this post, diabetes refers to canine adult onset diabetes mellitus, though less common juvenile onset diabetes and gestational diabetes also affect dogs.  There is also another uncommon form of diabetes that affects dogs called diabetes insipitus.   Other species, including cats and humans, are affected by diabetes too.

The Balance

Normally insulin and glucose balance each other on a moment by moment basis.  If a meal is eaten, the pancreas produces the appropriate amount of insulin to get the sugar from the meal to where it needs to go to run the body.  If blood sugar is low, the pancreas waits to produce insulin to process the blood sugar so there is enough circulating to make the brain happy.  In a healthy individual, the glucose and insulin balance each other to maintain health.

Cowboy Frankie

The Disease

Canine diabetes mellitus is characterized by persistent hyperglycemia.  With diabetes, insulin either did not show up to the playground (beta cell destruction), or is not being allowed to play on the teeter totter by the body (insulin resistance), and blood sugar, unchecked, becomes too high to remain healthy.

The Signs

The first and most notable signs of diabetes are often polyuria (excess urination) and polydipsia (excess drinking).  Dehydration may occur if the pet is unable to keep up with the increased need for water as the body tries to flush out the extra sugar.  Excess hunger, lethargy, urinary tract infections and skin infections are also common.  Pets may lose weight, even if they are eating more than normal.

If any of these signs occur, they warrant a trip to your veterinarian.  Many things can cause these signs individually or together, and an examination, bloodwork and urine testing will probably be the first steps.

The Diagnosis

Diabetes is diagnosed when blood glucose levels are found to be excessively high.

What’s Next

Injectable insulin is prescribed.  The body is either not making insulin or not responding to it, and exogenous (from outside the body) insulin brings the blood glucose back into balance.

Maintaining Balance

The insulin dose is carefully tweeked by the veterinary team based on blood glucose readings, blood glucose curves and, just as importantly, response to treatment.  If PU/PD has resolved and the pet feels well, that is AS important as maintaining glucose levels within the target range.  Fructosamine levels, urine glucose and other parameters are often monitored as well.

Secondary infections are treated.  The food type, amount and meal times may be adjusted.  If a pet needs to lose weight, a diet and exercise plan is carefully employed.  The trick to diabetic weight management is getting a pet in shape while ever keeping in mind that changes in calorie intake, food type and activity level will change the insulin/glucose balance in real time.  Insulin doses will need to be adjusted accordingly.


It can be tricky to determine what insulin type is best for an individual pet, what dose is best for optimal blood glucose control and how that dose will change over time.  So, understandably, after achieving initial stability and bringing secondary issues under control, complications most often arise from hyperglycemia or hypoglycemia.  And frustratingly, the two can sometimes look similar.

Hypoglycemia (low blood sugar) results from too much insulin.  It can cause disorientation, lethargy and even loss of consciousness (diabetic coma)  Hypoglycemia is a medical emergency, so have a plan from your veterinary team to deal with it, and bring your pet in right away if you suspect it.

Hyperglycemia (high blood sugar) is what probably preceded your pet’s diagnosis in the first place.  It too can cause lethargy, but tends to cause trouble in a slower, more methodical manner than hypoglycemia.  The most notable sequelae to chronically high blood sugar are kidney damage, liver damage, immune suppression and cataracts.  Hyperglycemia can also cause ketoacidosis, which is a medical emergency.

If your pet seems sick, bring him or her in for a veterinary visit!  Better a false alarm than a serious condition missed.  And honestly, there are very few false alarms with diabetes.  If your diabetic pet seems off, chances are you are right.

Enough Medical Information, How Are YOU?

What have been your experiences with canine diabetes?  Has it helped or hurt to have known other loved ones with diabetes?  Has control been straight-forward or difficult?  If you have walked this path before, do you have words of encouragement or advice for fellow pet lovers starting out?

Mardi Gras Frankie

K9 Diabetes

is a helpful site for families with diabetic dogs.  Add links in the comments to other sites you have found helpful!

May you and your your diabetic and non-diabetic pets live long, happy, healthy lives optimally maintained by consistently balanced levels of insulin and glucose.

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All Frankie Dog pictures are are provided by and used with permission of Edie Jarolim, who I assume got permission from Frankie.
UPDATE!  October 18, 2011  This just in!  Blame Genetics for Diabetes, Not Obesity by Edie Jarolim, published in the November edition of Your Dog, The Newsletter for Caring Dog Owners from Cummings School of Veterinary Medicine at Tufts University.