Dr. Kemmerer on adrenal
Deborah Kemmerer Cottrell DVM
West End Animal Hospital
15318 W. Newberry Road
Newberry, FL 32669
There are two adrenal glands, one near each kidney. The adrenal glands produce several very important hormones, including epinephrine (adrenalin), norepinephrine, cortisol (corticosteroid), estrogen, testosterone, and mineralocorticoid. Hyperadrenalism implies an over-production of any or all of these. In dogs and cats, 95% of hyperadrenalism is caused by the pituitary gland sending too much stimulation to the adrenal gland, making it produce too many hormones. This is true Cushing's Disease. In ferrets, hyperadrenalism due to pituitary disease is almost unknown. The cause is virtually always a tumor or enlargement of the adrenal gland itself. Which hormone is produced depends on exactly what part of the gland the tumor affects. It is not unusual for an adrenal tumor to affect more than one region at a time, thus producing multiple hormones and different symptoms.
Since adrenal tumors can produce different hormones in different amounts, the clinical signs can differ somewhat. The most common type in ferrets produces too much estrogen. In these cases, symptoms typical of estrus will appear. These include hair loss, enlargement of the vulva in females, enlargement of mammary tissue in either sex, and sometimes anemia and decreased platelet production. In cases where there is too much cortisol, there may be a dramatic increase in water consumption and urination, as well as thin, fragile skin and hair loss. In ferrets with too much testosterone, strong smell along with marking and mating behavior may occur. In ferrets with increased epinephrine and norepinephrine levels, an abnormally fast heart rate or high blood pressure may occur. This type of adrenal tumor, called a pheochromocytoma, can be responsible for deaths during surgery, due to an uncontrolled output of adrenalin when the gland is touched or stimulated. Fortunately, this type of tumor is pretty rare in ferrets and can usually be identified during surgery early enough to be handled properly.
Whether a ferret is treated with drugs, surgery, or a combination is an individual decision based on the general condition of the ferret, owner comfort level where surgery is concerned, and, of course, finances.
There is currently only one drug, Lysodren, which is officially recognized as effective against adrenal tumors based on large studies. Lysodren acts by destroying excess adrenal cells. Therefore, it can lower hormone levels and cause lessening of clinical signs.
However, it can also lower cortisol levels, thus causing a decrease in blood sugar. This can be problematic in a ferret with a concurrent insulinoma. We always recommend checking a blood sugar level before starting Lysodren. Lysodren is only effective in about half of adrenal tumors.
There are two newly popular drugs which show promise. Lupron and Tamoxifen both act by blocking estrogen receptor sites, and may prove useful. Another drug that is being tried is Anipryl, which is used to treat Cushing's Disease in dogs and cats. Unfortunately, Anipryl acts only on the pituitary gland, and therefore probably has little or no effect on ferret adrenal tumors. Although all of these drugs are relatively safe to try, all of them are quite expensive.
Surgical techniques are also controversial. Although removal of the left adrenal gland has become almost routine, removal of the right one is still a difficult, lengthy and sometimes dangerous procedure, due to the fact that the right adrenal gland is attached to the vena cava, the largest blood vessel in the body. You should speak frankly with your veterinarian to find out how comfortable he/she is with a right adrenalectomy prior to surgery. It isn't always possible to tell which gland is involved, even by use of ultrasound. At this hospital, we are developing a microsurgery technique that will allow complete removal of the right gland and attached portion of vena cava, with closure of the cut vena cava.
Whether treated with surgery or drugs or both, survival time for adrenal tumor patients tends to be good. In most cases, we can improve quality of life as well as quantity for several years.
Please don't hesitate to ask the veterinarian if you have other questions concerning your ferret's treatment. Adrenal disease can be quite complicated because there are many variables, and the more you understand, the more you can help your ferret by making informed decisions.
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