Originally Posted by
labblab
Hello again, Marissa. It took me longer to get back here than I thought, but finally here I am. Whew! Thank you also for providing so much clinical information. I have to admit that Bella's situation is indeed a bit of a puzzle. As Leslie has already noted, Bella does exhibit some lab abnormalities consistent with Cushing's, but at least in terms of her liver enzymes, the elevations are quite mild. Also like for Leslie, the whole picture does make me wonder about the overall accuracy of the Cushing's diagnosis. And yet, there are some specific issues that Cushing's would account for and I assume that's what's leading the vets to make the diagnosis.
One particular question that I have relates to Bella's ear lesions. You describe them as being calcinosis cutis -- was the CC definitively diagnosed via a biopsy, or are the vets labeling CC just based on the general appearance of the lesions? The reason why I ask is because a confirmed diagnosis of CC would vastly elevate the likelihood of an accurate Cushing's diagnosis -- it seldom presents in dogs in the absence of Cushing's. However, I can't say that we've ever had another dog here who exhibited CC on their ears. Typically it it is found in patches on the the back or flanks. Anyway, I'd be interested in hearing more about the nature of the issue with her ears.
One other question I have is whether Bella's thyroid level has ever been tested. A simple thyroid test is usually noted as "T4" on a chemistry panel, and maybe I'm missing it in your list of results, but I don't think I'm seeing it there. Cushing's is a disease that can cause low thyroid readings as a secondary result. However, hypothyroidism can cause skin problems as well as a few other symptoms that can overlap with Cushing's, and if a dog suffers from hypothyroidism as a genuine primary problem, it can be treated quite simply with oral medication. So I just thought I'd ask whether thyroid testing has ever been discussed by either vet.
Also, Leslie is absolutely correct that when beginning treatment, the initial dose of trilostane should be based solely on weight. So, at Bella's weight of approx. 12 pounds, a beginning dose of 10 mg. does indeed seem appropriate. However, subsequent dosing changes should be based on tested cortisol levels and clinical improvement. It looks as though Bella had a follow-up ACTH after around a month of treatment with a result of ACTH stim: pre 6.7, post 8.7. A dosing increase could have been considered at that time if symptoms persisted, but Bella's dose remained at 10 mg., with a subsequent test performed early January: ACTH stim: pre 2.9, post 6.6. (I'm assuming that the date for that test in your summary should be January of 2024 instead of 2023). I'm guessing these results are what are leading the internist to speculate that Bella may have been a bit undertreated since they could be lower in the presence of continuiing symptoms. However, given the fact that they declined from December to January while remaining on the same dose, I'm glad that the dose was not increased after all.
For what it's worth, I do think the internist's report seems quite comprehensive and reasonable. She's covering a lot of bases in a way that generally makes sense to me. So even though I can surely sympathize with the expense of the additional testing and the lack of a clear pathway forward at this time, I do commend you for consulting with the internist and I think her input is of value. I'm gonna go ahead and close for now, but I'll keep thinking about Bella's situation and add any more thoughts that come to my mind.
Marianne