Feldman: First, I believe veterinarians are doing a super job in the diagnosis and treatment of Cushing's. Owners should be informed
that treatment is elective — Cushing's treatment is rarely, if ever, an emergency. Dogs that are not treated usually have
progression of their signs — polydypsia, polyuria, polyphagia, panting, hair loss, pot belly, muscle weakness, thin skin and
so on. So if signs are not initially worrisome, give it some time. Also, it is important to let owners of dogs treated with
trilostane or mitotane know that both drugs have the potential to cause serious adverse reactions.
Have you observed any changes in the incidence of Cushing's disease in small animals? For example, are there fewer cases of
iatrogenic Cushing's, or are more cases being diagnosed because of better recognition and diagnostic testing by general practitioners?
Feldman: I have not seen any evidence that the incidence has changed. What has changed is a desire on the part of some pharmaceutical
companies and some specialists to have more and more dogs diagnosed. This has resulted in more and more dogs being treated
for Cushing's that, I believe, do not have Cushing's. The key in deciding which dogs to treat is to only treat dogs with obvious
and bothersome clinical signs. To put it another way, a veterinarian should not treat a dog for Cushing's unless he or she
would treat it if it were his or her own pet.
On a slightly different note, for your addisonian patients, after fluid therapy and/or glucocorticoid therapy, do you prefer
to use desoxycorticosterone pivalate (DOCP) injections or daily fludrocortisone orally for mineralocorticoid replacement?
Feldman: I prefer using DOCP injections. It is effective and more convenient for clients.
For cases of Cushing's as well as many other endocrine diseases, long-term treatment can be necessary. Given the tough economic
times, clients may be less interested in long-term management of diseases in their pets. How do you educate pet owners about
the benefits of diagnostics and long-term management?
Feldman: Well, your question is the answer. The key is to educate owners so that they understand the benefits and risks of either choosing
to treat or not to treat.
Finally, do you have any advice for veterinarians with an interest in expanding their practice's ability to diagnose and manage
Feldman: Read journals, attend quality lectures and have in-depth discussions with specialists on cases. Some wonder if they can trust
the opinion of a lecturer. Trustworthy speakers are those who publish in peer-reviewed, high-quality journals. Such speakers
have had their opinions exposed to peer review, and, thus, their opinions have been "assessed" by folks whose knowledge is
respected. Regarding trilostane, I would suggest that interested veterinarians read our 2008 paper in JAVMA and be on the lookout for a second paper on trilostane that will also appear in JAVMA later this year.
Thank you very much, Dr. Feldman. The information you have provided today about Cushing's disease points us toward better
diagnostic and treatment decisions and may encourage many veterinarians to step back and evaluate the need for treatment at
all. And all of us can benefit from the reminder to do a better job of addressing continuing education on a regular basis.
Edward C. Feldman, DVM, Dipl. ACVIM, is the chair of the Department of Medicine and Epidemiology at the University of California-Davis
School of Veterinary Medicine. He is a co-founder and former president of the Society of Comparative Endocrinology, a special
interest group open to all veterinarians, and is a co-author of the Textbook of Veterinary Internal Medicine with Dr. Stephen Ettinger and Canine and Feline Endocrinology and Reproduction with Dr. Richard Nelson.
Dr. Blake is a freelance technical editor and writer in Eudora, Kan.