From:
"meryl"
Date: 2011-03-01 20:59:20 UTC
Subject: [ferrethealth] Re: Iatrogenic Cushing's
To: ferrethealth@yahoogroups.com
Bonnie,
You've confused me too. Went to Pharmacy school 30 yrs ago and remember parts of pharmacology/physiology and of course have ferret texts, but this got me puzzling. I looked up definitions online to refresh my memory
"Cushing's disease is a cause of Cushing's Syndrome characterised by increased secretion of adrenocorticotropic hormone(ACTH) from the anterior pituitary. This is most often as a result of a pituitary adenoma; this, however, is a relatively uncommon tumour of the pituitary gland."
Also this website - http://www.newmanveterinary.com/Cushings.html it has descriptions of the various terms with a picture of Harvey Cushing. On it "Iatrogenic cushings" is described as
"In this form of hyperadrenocorticism, animals exhibit clinical signs as a result of excessive or prolonged exposure to exogenous corticosteroids." For example" "when a steroid-containing medication such as prednisone, dexamethasone, betamethasone, methylprednisolone, triamcinolone, or similar class of corticosteroid medication has been given orally, by injection or even topically (topical corticosteroid eye, ear or skin preparations, when used in excess or for prolonged periods, are absorbed into the blood stream) at high doses and/or for prolonged periods of time."
However, after reading the definition of Iatrogenic Cushings on the site, I was puzzled, my question is how can you prove this is the case in a ferret? How can they be sure the "adrenal disease" is caused by treatment for the insulinoma? One of my ferrets, Ferris, I took in as a rescue at 3yrs old. He had surgery - both adrenalectomy and removal of pancreatic tumors (he had not had any treatment by his previous owner)he had lowish bg and so had an exploratory - and they found adrenal and pancreatic tumors. She left part of one adrenal.
He then had good but slightly low bg for 2yrs then we started him on a low dose of pred,then higher, and bg continued slightly low normal, so we just had a second surgery. His one partial adrenal was still functioning and was a little enlarged, and his pancreas had tumors and they were successfully removed. To confuse things further he has been on lupron since his first surgery.
So in this case the two problems arose simultaneously - and steroids were not administered until after the first surgery. Guess since he has had both problems - insulinoma and adrenal tumors simultaneously - it doesn't really show that the two problems are associated - just that they arose at the same time.
Confuses the heck out of me. Are all ferrets with insulinomas who are on steroids then going to develop "Iatrogenic Cushings" and need adrenal surgery later? And is that what owners have noticed - ie treatment with pred for Ferris's insulinoma the cause of the adrenal remnant being slightly enlarged or was it a coincidence, or just because it had been proliferative to begin with?
also, how can you define the disease as iatrogenic cushings if many ferrets develop adrenal tumors before any steroid treatment starts? Have there been any surveys to show the adrenal tumors always develop if steroids are given? Do ferrets who do not get treated with prednisone or prednisolone still develop adrenal disease? Somehow I thought they did. Do most ferrets get pancreatic tumors before the adrenal tumors, or are they concurrent? Has anyone kept track on the age at which the diseases usually occur? Interesting problem.
Meryl
--- In ferrethealth@yahoogroups.com, "Bonnie" <ferretzrule@...> wrote:
>
> I am hearing of more vets diagnosing insulinomic ferrets on long term steroids with iatrogenic Cushing's, in fact, one of my own insulinomic ferrets received this Dx. His prednisolone dose has not changed in 3 years and is considered low.
>
> How exactly does the elevated cortisol cause adrenal (Cushing's) symptoms in ferrets? What role does the steroid induced cortisol increase play with estradiol, androstenedione and 17-hydroxyprogesterone? Could it be more likely that the ferret has just developed a proliferative lesion in the adrenal gland?
>
> Help! I'm sure I'm probably way over-thinking this.
>
> Bonnie Tormohlen (vet tech student who has a fried brain right now)
>
> Northern Arizona Ferret Alliance & Rescue/Director
> California Domestic Ferret Educational Alliance/Director
>
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