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adrenal disease

The adrenal glands are found above each kidney and are about the size of a grain of rice. The glands are made up of an outer wall (cortex) that secretes important steroid hormones including cortisol, estrogen, and testosterone; and an inner portion (medulla) that produces adrenaline and noradrenaline.

The hormones help control heart rate, blood pressure, the way the body uses food, and other vital functions.

Hyperadrenalism implies an over-production of any or all of these hormones. 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 called 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.

SYMPTOMS

  • Thinning of hair or hair loss on the body of the ferret.

    Hair loss typically begins with bilateral patches on the lower back, and on the upper tail area. In advanced cases, hair may only remain on the head and feet (see photos below). Some have been so bald as to have only their whiskers remaining.

  • Loss of muscle mass and a pot-bellied appearance.

  • Skin can appear 'thin' or almost translucent

  • Itchiness

  • Excessive water consumption

  • Aggressive or mating behavior. They may even exhibit mating behavior with inanimate objects, i.e. their blanket, stuffed toys, etc.

  • In females, an enlarged vulva is somtimes exhibited. In males, urination difficulties may be present due to enlarged prostate tissue and this can become life-threatening if not treated.

    Adrenal gland tumors usually affect ferrets over three years of age, though this condition can occur at any age. The disease is very common in the U.S.A, but is still fairly uncommon in Australia.

    Other names for adrenal disease include adrenal cancer, adrenal-associated endocrinopathy (AAE), hyperadrenocorticism, or adrenocortical neoplasia.



    LEFT: Delilah with advanced adrenal disease before her surgery.

    RIGHT: Delilah, several weeks after her surgery. Photos courtesy of Mike Janke.


    TREATMENT - Surgery

    Surgery is the most effective treatment for adrenal disease, and involves the removal of the affected gland (or freezing of the affected gland if cryosurgery is used). In the majority of cases and for reasons unknown, the left gland is most often affected. This is fortunate since removal of the left gland is relatively easy in comparison to the right gland. The right gland is often attached to the vena cava, the largest vein in the ferret's body, and removal can be difficult and dangerous.

    If you do decide to go with surgical treatment, be sure to ask your vet what his or her experience level is with right adrenal gland surgery. You don't want to put your ferret through major surgery only to find out after the fact that your vet didn't remove a diseased right adrenal gland because of the difficulty of its surgical removal.

    Contact us for more information about ferret-knowledgeable vets in the Canberra area.

    TREATMENT - Drug Implant

    Where surgery is not an option, due to age or health condition, there is a new implant which may help.

    Suprelorin (pronounced sue-prel-or-in) implants were released in Australia in November 2004, and are available to veterinarians through various vet suppliers.

    The implantís active ingredient is deslorelin, which suppresses the production of GnRH in the brain, which in turn suppresses the production of hormones from the adrenal glands.

    The implant does not generally affect the adrenal tumours, and in most cases they will contain to grow, which is why surgery is always preferable when possible. It does however, reverse the symptoms of adrenal disease, and we can assume it also makes the ferret feel a lot better.

    Most symptoms will begin to subside within around 14 days after insertion of the implant, with hair re-growth beginning after around 4-6 weeks. The implant is inserted under the skin between the shoulder blades, and lasts for around 12 months.

    The implants were originally designed for use as a contraceptive in dogs, but there has been at least one study done on the effects on ferrets with adrenal disease, with excellent results.

    The implant is not currently available in the USA, which is disappointing as many believe it is more effective than the current drug treatments available there (Lupron).

    Several Australian ferrets have received a Suprelorin implant since their release in November 2004.

    We have a copy of the study completed at the University of Pittsburgh, USA. If you are interested in reading it, please contact us.


    ABOVE: The Suprelorin implant and implanter needle

    Other drugs used to treat adrenal disease include:

  • Lupron (chemical name: Leuprolide) is widely used in the USA. This drug works in much the same way as Suprelorin, however it is more expensive and not readily available in Australia. It comes in 1,2 or 4 month depots (the drug is injected and slowly released over a 1,2 or 4 month period).

  • Mitotane (chemical name: Lysodren) was used many years ago to try and treat ferrets with adrenal disease. It is no longer used, as more effective drugs are now available. It works by destroying parts of the cortex (outer layer of the adrenal gland).

    Author: Shona Whaite

    Published in "Canberra Carpet Sharks": TBA






     
    Ferret Society of Canberra
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