Have you ever seen an old toy poodle with a severe dry hair coat and a noticeable pot belly who walks around panting all the time? This is a typical presentation for hyperadrenocorticism — Cushing’s Disease — which affects middle aged to older dogs. Although no exact number of patients is available, it is one of the most common endocrine diseases in the animal population, and in my practice seems to be increasing in incidence. Thirty years ago, I rarely identified a Cushing’s case; more recently, we diagnose upwards of 25 per year!
What is Cushing’s Disease?
Cushing’s Disease is a multi-systemic disease caused by an excessive production of cortisol by the adrenal gland. Most times it occurs spontaneously but it can also be produced by long-term overdose of prescribed glucocortion (steroids). The majority of cases are due to an over-growth of both adrenal glands in the dog’s body in response to chemical messengers made by a tumor on the pituitary gland in the brain. A small percentage of dogs (15%) have cancer of an adrenal gland itself, which over-excretes cortisol.
When we examine a patient suspected of having Cushing’s disease we typically find a thin hair coat on the trunk, a pendulous abdomen with muscle wasting, an enlarged liver, dark pigmentation of the skin, and sometimes visible bruising. The owners tell us that they have noticed their dog pants all the time, drinks more water than usual and seems to be ravenous — “He eats real good, Doc” — despite a good food supply. The dog is lethargic, not wanting to play.
Diagnosing Cushing’s Disease
Now the diagnostic fun begins. In a western conventional approach, we run urine tests and blood tests for internal organs, minerals, blood cell populations and specific hormones. In traditional Chinese medicine, tongue and pulse diagnosis play a big part in assessing our patients: The meridian pulses could be deep and weak or thready and fast. Tongue presentation could be pale, purple and wet or red and dry. There are actually three different analyses of Cushing’s disease in Chinese medicine, so tongue and pulse information will be different.
Other diseases that mimic some of the signs of Cushing’s disease must be ruled out with proper lab tests before therapy is started (hypothyroidism, sugar diabetes, liver or renal disease among others).
Once the proper diagnosis is confirmed, we have several options to consider. The most exciting one in our practice is the use of Chinese Herbal Medicines, which are given by mouth or mixed in food. We have seen a gentle reversal of abnormal signs without side effects. Laboratory tests have confirmed the return to normal cortisol levels and healthy liver enzymes in our Cushinoid patients. Did I mention there have been no ill side affects with the herbs? This has been a reason to celebrate!
The conventional treatment of Cushing’s disease has relied on prescriptions like Lysodren, Anipryl, Ketoconizole and Trilostane. These are potent medicines that target the cells that produce cortisol. Frequent blood tests are necessary to monitor the effects internally; sometimes ancillary medications are prescribed to counter the abrupt decrease in the body’s cortisol level. This, of course adds to the expense of managing medical control of Cushing’s disease. Efficacy for some of the standard drugs can be 20% or 50%, some of these drugs can cause too severe a reaction and produce hypoadrenocorticism (Addison’s disease) permanently. Side effects range from weakness, vomiting, diarrhea, liver disease, and lack of appetite.
In an ideal world, all or our patients would respond quickly to Chinese herbs and would be blood-test monitored once or twice a year. In real life we have had to resort to using a combination of Trilostane plus the herbs, but even in these cases we’ve been able to reduce the amount of the conventional drug, so side effects are noticeably fewer in our patients. Once treatment is established and blood levels show improvement, patients begin to resume their regular activities. They’re feeling better because they are no longer preoccupied with excess water consumption and skin/coat problems and are more energetic now that they’re not carrying around an enlarged belly. Pet owners report that they, once again, have their normal dog back. And that’s all we can ask for: a happy, healthy, fun-loving pet with a comfortable life ahead regardless of age.
Whichever route a veterinarian and pet owner choose together for the Cushing’s patient, clear communication and realistic goals of therapy are essential to a successful outcome. Knowledge, training and careful selection of herbal medicine are what every patient deserves.