? 3/14 Tibby - Dose at 7.5 units - need advice

Anna and Tibby

Anna and Tibby

Member Since 2020
Tibby has gone to a new home - we are seeing how it goes. In January she was getting good numbers with a dose of 6.5 and earned a reduction to 6 units and eventually settled at 6.25 and was doing OK for awhile with consistent blue/green nadirs and blue/yellow pre-shot numbers.

However, recently her pre-shots have gone back up to purple/reds consistently with yellow nadirs. This coincided with my friend who is now her caregiver being away for awhile and leaving the cat in the care of her husband, so we thought it might be stress response, but it has persisted now that she's back and with dose increases up to 7.5 units. She has also tried switching her food from a low-carb to even lower-carb food. Unfortunately, because she is away at work during the day she's not able to consistently get nadir readings.

Should she just keep increasing? or is it time bring her back to the vet to check for other causes?
 
Some cats do better on slightly higher carb food, going with the absolutely lowest carb food isn't always the best solution. Post here about that: Feeding Low Carb vs Lower Carb Foods

For those looking for the back story on Tibby's new home, read here.

As for Tibby's numbers, I rather suspect she has a secondary condition that is causing some insulin resistance. When cats get to 6 units per dose, we suggest that they get tested for a couple of those conditions, acromegaly (IGF-1 test) and IAA or insulin auto antibodies. One in four diabetic cats has acromegaly. Turns out my girl had both those condition. The tests are blood tests where the blood is sent to Michigan State University. For IAA, there is not treatment but time - though there are some impacts on dosing strategy. Think of IAA as sort of like an allergy to the injected insulin. For acromegaly, there are various types of treatments. It is caused by a benign pituitary tumour that sends out excess growth hormone. The treatments vary from just giving the amount of insulin they need, to surgical removal of the pituitary to radiation therapy. My girl had the radiation therapy. Since then, a much cheaper medication has come out that can help. Anyway, won't say more about that until/if we know if that's what we are dealing with. So this is time to see the vet about other causes.

The thing about conditions that cause insulin resistance, is that a dose that looks OK at one point can not longer be any good as the resistance grows. I used to call it "the dose growing stale". It may not have had anything to do with the change in caregivers.
 
Thank you both for those replies. No, she hasn't been tested for those things. Her last bloodwork was about a year ago. She has been on a dose of 6+units for about 6 months now, and her diabetes was uncontrolled for an unknown amount of time before that, up to 8 months, and controlled with a 1 unit dose for several months before that.

I guess I was under the impression acromegaly had other symptoms - she hasn't had the enlargement of jaw/feet and she lost weight, not gained when her diabetes was uncontrolled - but with more research I see that's not always the case. If it is IAA, it may have already been a year or more so I guess might end soon, so that would be good news.

Anyway, she's booked at the vet for the 29th. In the meantime, I assume we just continue to increase the dose as per the protocol?
 
Yes, just keep on plugging with the dose increases per the protocol.

My girl's only symptoms on her diagnosis were her incredible appetite (growth hormone like teenage boys!), and one teary eye, that I later found was due to blocked tear duct. Years later, she still didn't have enlarged feet and the jaw changes took 4 years to show up.
 
Update: her new vet is doing blood panel that will look for kidney issues and show if more testing is indicated re: acromegaly, and a fructosamine test. (I'm not sure the rationale for this as it's to check for glycemic control over the past few months - I'm not sure what this will tell us that existing data does not). He also suggested trying a different kind of insulin. We will see what the blood test results come back with tomorrow.
 
Blood work won't show if more testing is indicated. Anytime a cat gets over 6 units and is on low carb food, our experience here is that it is very likely either acromegaly or IAA (insulin auto antibodies) is present. The one thing about getting acromegaly and IAA tests done now, is one less blood work and vet visit charge if done later. And if Tibby does test positive, there are treatments that can help lower the insulin needs.

I agree with you, no need for the fructosamine test. That's a waste of your money when you can just look at the spreadsheet and see he's not regulated. But not all vets are comfy looking at spreadsheets, so the answer is for him, not for you. As for different type of insulin, at this size dose you might want to think about Levemir. At higher doses, Lantus has an acid base that can sting. And sometimes Levemir has better duration in larger dose cats, meaning flatter cycles.
 
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