Visiting Veterinarian : Juvenile diabetes
Early one morning, Katie's owners found that the little Jack Russell had tinkled in the kitchen. Almost two years old, Katie isn't a puppy anymore and it's unusual for her to have accidents. In retrospect, they agreed she had been drinking more water recently. "Maybe she's diabetic," her father suggested. Her mother wisely preferred a veterinarian's diagnosis.
Later at my office, dog and owner went walking to collect a urine specimen. Probably a bladder infection, I thought casually, taking the sample into our lab. The urine was clear, pale yellow, adequately concentrated. I dunked the chemistry strip, with its nine tiny squares that each tested for a different substance or quality - pH, bilirubin, ketones, blood, glucose. Glucose. Lots of it. In her urine, where it shouldn't be. I walked quizzically back to her mom. "Maybe she's diabetic," I suggested.
Diabetes mellitus (DM) is a metabolism disorder caused by an absolute or relative insulin deficiency. When Katie eats, her body digests food, breaking it down into simple sugars (glucose) that are absorbed into the blood. As blood sugar rises, the pancreas responds by secreting insulin. Insulin is a hormone that works like a courier, transporting sugar molecules from the blood into the cells where it can be utilized to fuel the body. Without sufficient insulin, sugar cannot get inside the cells where it needs to go. Katie eats and eats but loses weight. The high blood sugar makes her feel thirsty. She drinks and drinks... and then pees on the floor.
So what's up with Katie's pancreas that it's not making enough insulin? There are three types of diabetes mellitus. Type III is a condition where some other illness, such as Cushings disease, interferes with insulin activity. Relatively uncommon, Type III may resolve with treatment of the underlying disease.
Type II is the kind that afflicts many of us chubby, sedentary baby boomers. It is also the most common form in cats. Often triggered by obesity, as well as genetics, the body becomes resistant to insulin, requiring increasing work from the pancreas, until it just can't keep up with the demand. Type II diabetes can often be controlled with diet, exercise, and oral medication.
Type I is insulin-dependent diabetes. Thought to be an autoimmune disease compounded by genetic and environmental factors, the body's immune system gets confused and attacks the pancreas, destroying the beta cells that produce insulin. Treatment invariably requires daily insulin injections. In people, Type I used to be called juvenile diabetes because typical age of onset ranged from infancy to early 30s. Type I is the most common form of canine diabetes but, unlike in humans, usually occurs in middle-aged to senior dogs.
"I've never seen diabetes in such a young dog," I commented. "Let's run tests to confirm" Various breeds predisposed to diabetes may include German shepherds, beagles, schnauzers, cairn terriers, Samoyeds, and poodles. Juvenile onset is rare but more common in golden retrievers and keeshonds. Females are more often affected than males (although the reverse is true in cats).
Katie was a female, but otherwise didn't fit the typical picture. She was young, active, and fit, but there was no question she was exhibiting the classic symptoms of PP, PD, PU. That's polyphagia, polydipsia, polyuria. That's eating, drinking, and urinating excessively. Dogs with juvenile DM are also prone to exocrine pancreatic insufficiency (EPI) in which the pancreas fails to produce enough digestive enzymes. We confirmed the diabetes diagnosis, sent out an EPI test and, since all diabetics are prone to bladder infections, a sterilely collected urine specimen for culture. Then we got down to business.
"You're going to take over the job of Katie's pancreas by learning to give her insulin injections," I began. A normal pancreas responds to blood sugar fluctuations by constantly adjusting insulin output. We have to manage with just one or two injections daily. Most dogs need two. Veterinarians use many different protocols but the basic theory is always the same. A predictable, high fiber diet fed on a specific schedule, usually two to three meals daily. Insulin injections. Monitor blood sugar.
Some owners learn to use a glucometer to test the blood at home. I am more old school. Most of my clients monitor with the less invasive urine test. When blood sugar is extremely high, it spills into the urine. By testing how much sugar is in the urine, we can approximate blood sugar levels. If Katie has high urine sugar, her owners will increase her insulin. If there is little or no urine glucose, they will decrease it. They will always watch for hypoglycemia, i.e. low blood sugar, manifest as weakness, staggering, vomiting, incoordination, seizures, coma, even death.
"Keep some Karo syrup on hand, "I warn. "If Katie seems woozy, feed her. If she doesn't improve quickly, give her Karo syrup. If unconscious, rub syrup on her gums but don't try to give her anything orally, and call me immediately!"
We will monitor Katie periodically, having her stay for the day while we check her blood sugar every few hours. This helps us learn when her insulin reaches peak effect and how long it lasts. Sometimes we need to try different types of insulin to get the peak onset and duration right. Other times, we might test a single fructosamine level, which gives us a ballpark idea of how her regulation has been over the preceding few weeks.
It all seems daunting at first, but, like most owners, Katie's family is adjusting. Juvenile doggy diabetics are reportedly more difficult to regulate than older dogs, but so far, so good. We have confirmed concurrent exocrine pancreatic insufficiency. She will need to take oral enzymes to help digest her food properly, and lifelong insulin, but as we get her blood sugar under control, the PP, PU, PD will resolve and there should be no more puddles on the kitchen floor.