One of the most common conditions that ferrets are treated for is Hyperadrenocorticism, or adrenal disease. This is not to be confused with Cushing’s disease, more commonly seen in dogs and cats. The difference is where the problem lies: In Cushing’s disease, the affected organ is usually the pituitary overstimulating the adrenal glands, causing the oversecretion of hormones. In hyperadrenocorticism, a neoplasia or tumor is growing on the adrenal gland, causing it to be overstimulated. Traditionally, drugs used to treat Cushing’s disease are ineffective in ferrets.
The adrenal glands are located near the kidneys, with the right adrenal gland adjacent to the vena cava. The glands secrete many hormones, including epinephrine, cortisol, estrogen, testosterone, norepinephrine, and mineralocorticoid. The oversecretion of these hormones causes hyperadrenocorticism.
Diagnosis of adrenal disease is almost always done based on clinical signs. The Endocrinology lab at the University of Tennessee has a blood test for detecting adrenal disease and the cost to a vet is $75.00. Most knowledgeable ferret vets will only consider running this test should the signs of the disease be questionable. Symptoms of ferret adrenal disease include: symmetrical, bilateral alopecia, a return to sexual readiness (aggression in males, swollen vulva in females), weight gain, a change to the skin texture (becoming more papery-like), increased odor and muscle loss. Most hairloss starts around the base of the tail, works up the spine and across the shoulders and in advanced cases, includes complete hairloss except for the face and feet. Male ferrets are particularly susceptible to swelling of the prostate, which may secondarily cause significant problems – partial or complete blockage of the urethra.
The preferred method of treatment for ferrets involves surgical removal of the affected gland(s). Bilateral adrenalectomy, while uncommon, can be performed, with usually no follow up hormone therapy – the right adrenal gland is adjacent to the vena cava, making complete removal difficult or impossible, so oftentimes adrenal tissue remains behind. In some bilateral adrenal cases, corticosteroid replacement therapy is necessary.
Surgery is the best chance of curing the ferret of adrenal disease – no one gland appears to be more affected than the other, so if it is a left side adrenalectomy, there is a very good chance of no recurrence of symptoms. Right side adrenalectomy can result in a second surgery for debulking the gland at a later date.
A new type of surgery, cryosurgery, is being used with excellent results. Dr. Charles Weiss, an innovative ferret vet located in Maryland, has performed extensive testing and surgeries on ferrets is very excited about this latest advance in adrenal surgery.
If surgery is not an option, there are a couple of medications which will help control, but not cure, adrenal disease. Lysodren, or Mitotane, is one of the most common chemotherapy drugs on the market. Lysodren acts by destroying excess adrenal cells – which means it could be killing good tissue as well as bad. Lysodren has one noted side effect: it lowers cortisol levels and causes a decrease in blood sugar. Any ferret on Lysodren is strongly recommended to have blood glucose levels checked prior to starting and periodically while on the medication. Anipryl, a medication used to treat Cushing’s disease in cats & dogs, has been tried with little or no effect on the tumors, as it targets the pituitary gland. A newer entry into the treatment of ferret adrenal disease is Lupron. Lupron acts to decrease the levels of estrogen and testosterone and appears to be effective in reducing the signs of the disease over time. A newer protocol for Lupron is now available from some compounding pharmacies to the vet in which the powder is separated into individual doses and the diluent provided. Once mixed together, it is highly recommended to be given immediately.
Treatment for the disease, whether surgical or medical, is essential. Male ferrets are particularly at risk for prostate problems – they can become cystic and inhibit urination – causing at best, a urinary tract infection and at worst a complete obstruction of the urethra. Overall, ferrets of either sex do not just lose their hair, they lose muscle mass and tire easily, some even losing use of their limbs. Quality of life is absolutely decreased and if left untreated, becomes life threatening.
Adrenal disease is treatable – and in some cases expensive (surgical costs usually start at $300.00), but the cost alone should not be the reason to pursue medications to control the disease. In the long run, the surgery may actually be cheaper than the cost of monthly injections or treatments, depending on the lifespan of the ferret. I have had excellent results from adrenal surgery, with the longest-lived ferret at 5+ years post operatively, with no recurrence of the disease. As with any surgery, risks associated with anesthesia must always be taken into account. Even some of the more advanced cases coming into the shelter ( 6+ years of age, 80% hairloss, swollen vulva) did well – with hair regrowth over most of the body within 3 months. Hair regrowth can be delayed until the next shedding period, so patience is sometimes warranted. Of the 20 ferrets that I have had adrenal surgery performed, only 6 were bilateral; 3 died as a result of surgery (one from depression, the others from unknown causes almost directly after surgery); 7 had complete recovery; 1 is waiting for surgery; 1 is recovering from surgery; and 4 had a recurrence of symptoms and were placed on medication therapy. Of the three that died, there were no indications that they would not do well — all presurgical screenings showed excellent candidates.
In closing – adrenal disease is an easily diagnosed, treatable condition and surgery should always be considered as your first and best option, because ferrets as a general rule tolerate surgery well. It is not a condition that should be ignored or considered merely as a “cosmetic” fix. Watch over and treat those balding ferrets as soon as possible.