I get some great questions from clients. They inspire me with article ideas and keep me in tune with diabetic pet owners. I enjoy interacting with our readers, and sometimes the questions are worthy of a newsletter. I bet if one person has this question and takes the time to write me, there are likely lots of folks with a similar question. Today we’re going to talk about hard to regulate diabetic dogs.
Dr. Joi, I enjoyed your article about hard to regulate diabetes in cats. I have an 11-year old Labrador that was diagnosed with diabetes this past Nov. He does not seem to be responding as well as he should be. He was checked for Cushings which was negative. He is getting 29 units of Novolin 2x per day now. Do you have any more ideas of what could be causing the insulin resistance? I am interested if you have any ideas. My vet has me checking his blood glucose 3 times per day. Do you think the every 2 hr. curve would give more specific info?
Answer: Well, I guess the first thing to ask is how are his blood glucose curves? That is your best indicator of how well he is responding to the insulin. He may not have insulin resistance. It may just be that you haven’t yet found his best dosage of insulin.
Blood glucose curves give us so much information when done right! When I run a curve I test the blood glucose every 2 hours from one injection until the next, for a 12 hour period. And, if the blood glucose goes below 150 mg/dl, I test hourly until it rises again. This way I know when it truly bottoms out, aka the “nadir”. Curves tell us how long a particular insulin lasts in a particular pet and also if we can increase the dose or if we need to lower the dose. For example, if the curve bottoms out at 50mg/dl, we need to lower the dose. If it bottoms out at 200 mg/dl, we would increase the dose. We need numerous samples to see where it bottoms out. Sometimes folks email me their glucose curve numbers. I cannot evaluate curves for pets I haven’t personally examined, as that would be bad medicine, but you now have the parameters I use. You and your veterinarian can evaluate the curves together to alter the dosage if needed. Remember, pets may vary in their absorption and metabolism of insulin. No two pets are exactly the same.
Ideally for a curve, we want most of the numbers below 300 and we want it to bottom out somewhere around 100. The renal threshold for sugar spilling over into urine is somewhere around 250 to 300 mg/dl in pets. So if we keep most of the numbers below 300 the clinical signs of diabetes like excessive thirst and urination are abated and quality of life is improved. Make sense? Testing just 3 times per day doesn’t give us that information. Curves will help you and your vet fine tune his diabetes and find out if he is insulin resistant. I strongly prefer these curves be done at home to avoid stress hyperglycemia. After adjusting an insulin dosage we will wait 5 to 7 days before doing another curve to assess the new dosage.
Have you also ruled out infections? Urine culture and dental care are helpful if you truly think there is insulin resistance. Urine cultures are horribly expensive. I’ve seen vet clinics charge anywhere between $100 and $150 for a urine culture. Most of that money goes to the lab, not to your vet. Because of the high cost of urine cultures, I ordered an in house urine incubator, called the Uricult Vet, 5 years ago. I found it at a vet conference exhibition area where they sell all kinds of gadgets and gizmos that keep veterinary medicine fun and exciting for us veterinarians getting long in the tooth. It was a dandy idea to make microbiology so simple that any vet can do it in a small private clinic setting.
The incubator comes with a box of paddles. Each paddle has 2 different culture media on either side and it fits into a plastic vial that goes into the incubator set at 36 degrees Celsius. The paddles cost less than 10 bucks each. It will cost you more than that as your vet needs to pay for the incubator and the effort and time to collect the urine via cystocentesis and then monitor the paddle for growth of bacteria. Nonetheless, it’s a lot less than sending it out to an outside lab. If I expect a urine culture to be negative and am checking to be thorough, say for a diabetic or maybe a blocked cat or newly diagnosed kidney patient, I nearly always start an in-house Uricult Vet. If I have seen bacteria on an in-house urinalysis and sincerely need to know the best antibiotic choice to combat it, I’ll send urine to an outside lab for culture and then sensitivity testing against various antibiotics. Sometimes I may send urine out and additionally start a Uricult vet in-house as sometimes, but rare, germs may die in transit to the outside reference lab. You might tell your vet about it! It could then potentially save you big bucks since you have a diabetic pet. I recommend urine culture every 6 months for diabetic pets.
Now, is he proper body weight? Labradors are known to be food motivated and can be tubby. Obesity is a very common cause of insulin resistance. Is he getting mid meal snacks? Those can cause unwanted blood glucose elevations! Additionally, I consider how he is feeling. Does he play? Is he drinking and peeing excessively? Is he gaining or losing weight? Is he forever hungry? Does he feel well?
Have a sit down with your vet and if you haven’t done a recent blood glucose curve, do one.
Keep me posted!
Have a question or comment? Post below or email me at firstname.lastname@example.org. I always enjoy hearing from my readers!
NOTE: Consult your veterinarian first to make sure my recommendations fit your pets special health needs.