Adrenal disease is primarily found in ferrets over 3.5 years of age, but has been seen as early as 9 months. Clinical signs can be any combination of the following: hair loss, either just on the tail or symmetrically over the body, periodic shedding of the complete coat with full re-growth each season, itching between the shoulder blades, generalized itching, weight loss, lethargy, enlarged vulva and heat activity in spayed females, aggression and mating behavior in neutered males, urinary straining and/or blockage in males from enlarged prostatic tissue.

Okay, you know that your ferret has adrenal disease. What do you do? All sources I've checked, as well as my own experience, indicate that surgery is the best choice in a healthy ferret. Ninety percent or more of affected ferrets can be cured by surgery. Even older ferrets (>7 years) can do well after the affected gland is removed, though caution should be taken with these geriatric cases. Post surgical sudden death is far more common in ferrets >6 years of age. An exploratory surgery may also reveal other problems, including intestinal foreign bodies, insulinoma, hypersplenism and/or lymphoma. Supportive care is extremely important before, during and after surgery. The majority of these surgeries are uncomplicated, involving only the left adrenal gland. Approximately 10% with be complicated, involving the removal of both adrenals or resection of a portion of the vena cava. It is highly recommended to biopsy the tissue to determine that diseased tissue has indeed been removed. Treating your ferret for adrenal disease requires case by case consideration as there are differences in anatomic presentation.

In the event that your ferret is not a good surgical candidate or lack of money prevents surgery, lysodren (mitotane or o, p DDD) therapy is the most common medical treatment currently in use. It can also be used in ferrets with bilateral disease where both entire glands could not be removed. At best, lysodren treatment causes improvement in 15-30% of cases. As this therapy can cause low blood glucose in some ferrets, regular monitoring of blood glucose is necessary. Lysodren seems to be most effective in adrenal hyperplasia or adenoma, but has limited or no effectiveness with adrenal adenocarcinoma.. If there is no response within 12 weeks, therapy should be considered ineffective. Side effects of lysodren use include low blood sugar (hypersalivation, hind limb weakness, depression, glazed eyes), anorexia, vomiting and lethargy. If any side effects are noted, therapy should be discontinued. Individual cases of allergic reactions to lysodren or the other ingredients added in compounding (lactose particularly) have been noted. Several experimental treatments are being used on trial by various ferret knowledgeable veterinarians. The best medical treatment for your ferret should be chosen after thorough discussion with your veterinarian.

There have been several antecdotal stories regarding various herbal, nutritional and environmental changes to alleviate adrenal disease. Until these methods have been scientifically tested, I reserve judgment on their use, leaving that decision to each owner and their veterinarian.

NOTE FROM FERRET WISE
Dr. Weiss wrote this post on July 26, 1998, for FML and FAIML readers and their veterinarians.

I have performed about 10 of these procedures to date. All the ferrets have survived and are doing well. In my opinion vena cava ligation can be a life saving technique which should be performed with select cases. The right adrenal gland in the ferret is normally attached to the vena cava, which makes it a technically difficult surgery. Although difficult, an experienced ferret surgeon usually can perform this procedure without ligating the vena cava, with very good success. I do not feel the vena cava should be ligated routinely, or because the adrenal tumor is "attached" to the vena cava (it is virtually always attached to the vena cava). On occasion we see very large right adrenal tumors which almost completely occlude (obstruct the blood flow through) the vena cava. In these cases the tumor grows over weeks or months slowly occluding more and more of the blood flow through the vena cava. When this occurs over this time frame the body develops collateral circulation (other small new blood vessels that bypass the vena cava). Therefore when the vena cava is almost completely occluded I feel it is usually safe to ligate it in the ferret. The other alternative is closing the ferret up and calling it an inoperable tumor (which is giving the ferret a death sentence). With the option of vena cava ligation virtually all adrenal tumors are operable. This is really a benefit to the patient since even malignant adrenal tumors rarely spread and complete removal is usually curative.

When used appropriately I feel this is a life saving technique which has minimal complications. But, it's important to remember that a ferret with a large adrenal tumor is a very ill animal (even if it comes on so slowly that the owners do not notice many symptoms). Although this is a very stoic species which does not always display pain as we do, this is a life threatening condition. In a case like this there are always risks associated with anesthesia and surgery, because it is such a serious condition. In my opinion, in such a case, surgery with vena cava ligation is the best chance to save the patient's life and give the ferret a good quality of life post- operatively.

Charles Weiss, DVM