? Returning Member...question regarding lower glucose readings

Hello! I haven't posted for a while but I have a question regarding all of a sudden getting lower glucose readings. Peanut is an insulin resistant cat. In July we put her to a 7.0 dose twice a day...she is on Lantus. I do glucose readings sporadically just to see where she is at. I have the spreadsheet updated and the new link in my signature.

Yesterday she was more active than usual, so we decided to test her. She was at 145!!! We have NEVER seen a reading under 300. And we have just recently started seeing readings in the 300s. I gave her food and at her PMPS, she was at 363. Today I tested her again and she was at 249...this was at the 8.5-hour mark. These readings are super odd for us. I even did the control solution again to make sure the monitor was working correctly. Then today I had to change to the new container of test strips, so I had to do the control again. Everything with the monitor seems to be working ok.

Peanut's eating habits are the same. I haven't changed the food. She was a bit slower at the beginning of the week, but she sometimes has off days and then thankfully bounces back.

Any insight on the lower readings would be great. We are actually afraid to leave her alone!
Thanks!
Karen and Peanut

The first thing that occurs to me is that Peanut is on a big dose of insulin. Generally, when a cat is needing more than 6.0u, we suggest getting the cat tested for a high dose condition -- either acromegaly or insulin resistance (insulin auto-antibodies). With acro, there is a growth hormone secreting tumor in the pituitary gland that causes the high numbers. The tumor can pulse so there are times when numbers are high and times when the numbers drop. This was once thought to be a rare condition but more recent research suggests otherwise.

IAA is a self-limiting condition that causes your cat's body to respond to insulin almost like an allergy or a foreign substance and the immune system works to defeat its action. Thus, the result is high numbers and the need for increased amounts of insulin. At some point, the insulin defeats the response and numbers come down.

This is a link to information on these conditions. To test for these conditions, your vet will need to send blood to Michigan State University. There is a link to the information on getting the bloodwork in the post.

I suspect there is also a bit of bouncing going on. Peanut is used to being in high numbers. When his numbers drop, even into the 300s or low 400s, his body may be reacting to the lower numbers. You don't routinely do much PM testing so it's hard to know what's going on in the evenings and if the numbers are lower than what you're used to seeing.

I'm tagging @Wendy&Neko who is very experienced with high dose cats.

Thanks! Yes, Peanut is on a very high dose. Our vet will not do any other testing than what they have done. We have to find an internal medicine vet that will do the further testing. Peanut does possibly have an enlarged heart so that may be causing the insulin resistance.

I can start testing more in the PM. I am actually going to go do a test now because she is due for her insulin shot. Last night, because she was so low, we reduced the dose to 5.0. Depending on what she is now, we may do the same.

I just did her test and she is at 254.....we aren't sure if we should even give her a dose???

Typically, it would be fine to give insulin with numbers in the mid-200s. I can understand your reservation, though since you're not used to seeing lower numbers. You can always stall for a bit to see if numbers are on the way up. Keep in mind, that you will also be feeding Peanut and both food and the insulin from the previous cycle wearing off, means it will be a while before this dose starts working. I would encourage you to get early tests -- like at +2 or +3. Alternatively, you can shoot a reduced dose.

But what dose would we give? I was petrified to give her usual dose of 7.0u. I am going to test her again in a bit...probably at 930pm EST. We didn't give her anything yet. (Her usual time for shots is between 730 and 800 both in the AM and PM). Last night at the pre-PM shot she was at 363 so we gave 5.0.

I just tested her....279.....going to wait to give her a shot and will test again.
Thank you for your help with this!!!
Karen and Peanut

Hello again Karen and Peanut. Congratulations on that 145 yesterday! That's a really good start. As Sienne suggested, Peanut could be seeing more numbers in the 100's overnight, and then bouncing. Many cats see lower numbers at night.

Karen and Peanut said:

Peanut is on a very high dose.

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I would say, higher than the average diabetic, but still not that high. Neko got up to 8.75 units. I've seen cats with insulin resistant conditions (acromegaly and/or IAA) on much much higher. Think filling two syringes with insulin sized doses. The 2015 study that found how common acromegaly is, about one in four diabetic cats, found that 7 units was the average dose in their study.

Size of dose has nothing to do with changing what dose you shoot at lower preshots. We change dose based on how low the dose is taking kitty overall - at any point in the cycle. I didn't blink when shooting Neko in the 80's preshots when she was getting 7.0 units of insulin. It meant a nice flat cycle was likely to follow. For some reason, she really liked the 80's.

I would shoot Peanut's normal 7.0 unit dose. If you wait too long without feeding, the numbers can drop without food.

I would also encourage you get the testing done for the secondary conditions. There are treatments out there but you have to know what you are dealing with first.

Karen and Peanut said:

Peanut does possibly have an enlarged heart so that may be causing the insulin resistance.

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I forgot to reply to this comment too. It's also possible that the insulin resistance (acromegaly) is causing the enlarged heart. The excess growth hormone from the benign pituitary tumour causes excess growth in bones, soft tissue, and organs. We don't typically see an enlarged heart by itself causing insulin resistance, unless there is another heart issue along with the HCM.

Thank you for the information!!!
We didn't give her the usual shot last night. We were scared. The info about your kitty being in the 80's and still shooting the higher insulin is awesome info. We were afraid she would crash. I tested her at 1am and she was at 525 so we gave her 4.0u. Then this morning at 7am she was at 521 so we gave her an additional 5.0u. I know this is probably not ideal but like I said, we were scared! I am going to test her throughout the day and see where she goes. I updated the spreadsheet as best as I could to show the odd shot we gave early this morning. I will say when her numbers are in the 100s and 200s, she is like her old self...something we haven't seen since earlier this year.
Thank you again!!!
Karen and Peanut

Do your best to keep to a 12-hour schedule. The reason is that you don't want the timing resulting from shooting off schedule to cause overlapping nadirs. If that occurs, you can end up with lower than expected numbers.

If the 1am last night was at +6 (if you had shot last night), also called +18, could you do the following on the spreadsheet. First, move the +12 or PMPS value to the +11 cell with the note 254@+12. In the PMPS cell, write 525@+18, then the dose of 5.0 in the Units cell. For this morning, put 525@+6 in the AMPS cell and 4.0 in the Units cell for the AM. The changes will mean you don't need two lines for today in the SS and will show us you delayed the PM shot by 6 hours and shot this morning 6 hours early.

The above is if 1AM is your +6. Adjust times as needed if that's not exactly right.

Note, since Peanut is not used to blues, I was expecting a whopper of a bounce. Another reason to have more confidence shooting lower numbers.