Experience with Cushing's Disease in dogs?

In My Humble Opinion
1

First off, I’m scared shitless. Recently I took my beloved, 8-yr. old Black Lab/Shephard mix in for her annual senior wellness screening. Once again the test came back with elevated functions in the blood work. (They have for a couple of years; she’s been on prescription low-fat chow for several years and she’s never gotten table scraps. Her weight’s fine at 71 pounds, so it isn’t diet. We’ve been watching that closely.)

She has no symptoms at all but the vet is doing a full-day test on Tuesday for Cushing’s disease. I’ve been reading up on it–and it’s scary. Obviously the test hasn’t even been done yet, and the vet said there are therapies available even if it comes back positive. And if it is Cushings, we’re catching it very early. But much of the written info seems contradictory, especially about shortening lifespans and the side effects of therapies.

Does anybody have experience with this? I’m trying to stay positive and not borrow trouble but this has me scared. Badly scared. Any advice for Doper dog lovers?

Veb

2

My dog is 15 and an American Eskimo breed and he has canine cushions disease. He was diagnosed with it in the hospital, because doctors thought he had the symptoms of it. Fatter belly/bloated, lots of panting, drinking lots of water and sleeping a lot. So the our vet took tests which take a day or rather he is kept there the day and sure enough was diagnosed with cushions. He is prescribed Lysodren to manage the disease. In the beginning these tests were every few weeks to figure out the levels of hormones to the dosage. And to tweak the hormone to pill dosage. Now he is taking a pill once a week for it. They are apparently very strong pills so if there is any sign of stomach upset nausea, you must discontinue use immediately and call your vet. When he gets sick, or is not eating, we call the vet and stop all pills. After a few days he is fine. I don’t know what else to tell you really. From what I read, the pill is the equivalent to chemo and its very strong, but my dog has severe arthritis, a poo problem, so he takes Fortekor and Rimidyl. I can say the tests and meds for this is kind of expensive. And once your pills run out, you have to take him in for a test before the pills run out in his system so that there isn’t a discontinuation. I think the surgeon was saying there were two types of the disease. I think my dog has the glandular one. Anyways, that’s my experience with it. Hopefully it helps a little.

3

Well, I have no experience with canine Cushing’s, but I used to be an endocrinologist (seriously) and some of my patients were real b…

I’ve checked out (superficially) a large number of web sites and it seems to be that, to a very large extent, human and canine Cushing’s are quite similar.

As background, note that the pituitary gland makes a hormone called ACTH and the ACTH stimulates, in turn, the adrenal gland to make cortisol. Cortisol is vital and life-sustaining. In theory, then, too much cortisol could result from a pituitary overproduction of ACTH, or a primary problem of overproduction of cortisol by the adrenal gland.

Just as in humans, canine Cushing’s is much more likely to originate from a pituitary gland problem than from a primary adrenal gland problem. In particular, in 85% of canine Cushing’s, there is a small (benign) tumor in the pituitary gland. The tumor produces ACTH - the substance that normally stimulates the adrenal glands to make cortisol. The more ACTH, the more cortisol. The net effect of the tumor, then, is too much cortisol. (And too much cortisol = Cushing’s with all its attendant manifestations).

Although the usual treatment for humans is removal of the pituitary tumor (by neurosurgery), I gather that is infrequently used for dogs (but can still be done in an expert center).

In the absence of pituitary surgery, one is forced to accept the ongoing presence of a persistent (benign) pituitary tumor. Hence, treatment is directed at preventing the large quantities of ACTH produced by the tumor from having any effect on the adrenal glands to produce cortisol. So, medications are given to prevent the adrenal gland from responding to the ACTH. Mitotane (op’DDD or Lysodren) does this by damaging the adrenals, whereas ketoconazole does this by interfering with the normal biochemical pathways within the adrenals. It is the safer, but less effective, of the two. The main danger with Mitotane (in humans) is damaging the adrenals to such an extent that too little cortisol is produced. That is the opposite of Cushing’s and is called Addison’s disease. Should it occur, one easy (and only slightly paradoxical) treatment is to give cortisol (!)

I can speculate that although it may be possible to reduce the levels of cortisol using Mitotane or ketoconazole, the untreated and still growing pituitary tumor causes problems. Although benign almost 100% of the time, it still expands and compresses the rest of the pituitary. This leads to impaired production of the other pituitary hormones and that can be problematic. Further, the tumor may expand and threaten the visual nerves or even the brain itself. Both of these sequalae could well shorten life expectancy.

One thing seemed clear from my quick perusal of the veterinary links - that there is a good deal of experience with it. That is not the case with human Cushing’s Disease, where few docs have seen a real case. That may bring you some reassurance.

4

There is a lot of information that “seems contradictory,” especially on the internet where anything you see could be true or false. Even published information can be “out of date” as theories, treatments and medications change as the result of testing and progress.

That being said, here is a very good site on Cushing’s disease in dogs:

http://www.marvistavet.com/html/cushing_s_disease.html

In addition to sections on explaining what the disease is and how it’s caused, information about the tests and the different treatments compared, there is also a link to two listserv’s of other owners who’s pets have Cushing’s Disease.

The author is a veterinarian who is a board-certified specialist in Canine and Feline prectice, and the information is duplicated on a site run by VIN, the Veterinary Information Network, a site for veterinarians, in their public health care section: www.veterinarypartner.com (in this case, Cushing’s Disease).

Good luck.

5

Cherry gave you good advice. What I’d like to re-emphasize, though, is that is is critical for your vet to run follow-up blood tests during the initial Lysodren dosing. Do not miss an appointment and know what exactly you need to look for while your dog starts this medicine, if that’s the route you choose.

Our vet was inexperienced with Cushings and Lysodren and didn’t even tell me what to look for (vomiting, anorexia, weakness) that indicated the medication needed to be stopped. My golden retriever went into an Addisonian crisis and nearly died, spending 3 days in the ER and losing 30% of her body weight.

Lysodren works very well, but it can be very dangerous, too, and it must be monitored diligently. You’ll also want your vet to give you prednisone to keep on hand to administer should your dog show any signs of Lysodren toxicity.

Treating Cushings in a dog is a tricky business. The disease itself will lead to organ damage, but the treatment isn’t risk free, either. I wish you much success with your pooch. FWIW, we discontinued treatment after the crisis and Molly lived another 2 years (to the age of 13) with kidney failure. She was PTS because of a malignancy completely unrelated to the Cushings.

6

Thanks much for all the info, guys. I appreciate it more than I can say.
Da Pooch goes into the vet’s for her intiial test at 7:30 a.m. on Tuesday. I guess we’ll just have to wait until the results are back.
I’m hoping, of course, that it turns out to be nothing. She appears perfectly healthy and happy. But those unusual blood factors have been present in her past two check ups. Something’s causing them, but I hope against hope that that something is minor.
Mainly I want her around just as long as possible. But the quality of her life is important too.
Well, at least you’ve given me some solid grounding on a few of the “what ifs”. My pup and I thank you!

Veb