Ferret Adrenal Disease

Updated: September 24, 2014

Adrenal gland disease is caused by hormone-producing tumors of the adrenal gland. It is an extremely common condition, most often affecting ferrets over three years of age. The adrenal glands are a pair of endocrine organs located in the abdomen near the kidneys. In this disease, one or both adrenal glands become hyperactive and start to overproduce sex steroid hormones, such as estrogens and androgens. The high level of hormones are then responsible for a myriad of symptoms including hair loss, anemia and urinary tract obstruction.

The adrenal gland tumors can be benign and slow growing, or malignant. Benign tumors secrete excessive hormone, but do not become large enough to compress other organs or cause symptoms typically associated with malignant cancer, such as weight loss. Malignant tumors can grow quickly and compress other organs, and cause weight loss, weakness and other systemic effects, along with secreting excessive hormones. The cause of this condition is unknown but may be related to the young age at which pet ferrets are often neutered or genetics.

Adrenal gland disease is only seen in both males and female ferrets. The incidence increases with age, making the majority of affected ferrets over three years of age. Younger ferrets can also develop the condition.

The hormones produced by this disease are responsible for most of the problems of adrenal disease. The most common effect is hair loss that may be subtle at first but typically progresses over time. Most ferrets are excessively itchy. Some of the hormones can cause enlargement of the prostate gland or other tissues around the urethra, resulting in trouble urinating, which can be life-threatening.

Because these hormones are sex-related hormones, like testosterone and estrogen, affected ferrets may develop signs of being “in heat.” They may develop a bad odor, the male can become sexually aggressive toward the other household ferrets, and most females develop a swollen vulva.

What To Watch For

• Hair loss, resulting in bald spots
• Excessive scratching
• Increased body odor
• Trouble urinating or defecating
• Swollen vulva
• Vaginal discharge
• Increased aggressive behaviors

Diagnosis

There is no simple, single test to confirm adrenal disease, and many cases are diagnosed based on symptoms alone. Diagnostic testing is important; however, to determine if the tumor is malignant, to evaluate the overall health of the ferret, and to see if the adrenal condition has led to other complications.

• Abdominal ultrasound (sonogram) is a relatively simple and safe test to evaluate the size of the adrenal glands and a test for prostate enlargement. This will also determine if the tumor is in right or left adrenal, which is important to know prior to considering surgical treatment. Monitoring the tumor with ultrasound is helpful in detecting potentially malignant tumors. Radiographs (X-ray’s) are not as helpful.
• Complete blood count (CBC) and platelet count are recommended to evaluate the activity of the bone marrow. Most veterinarians also run a plasma chemistry panel to assess overall health of the ferret and check for concurrent diseases.
• Plasma hormone testing will confirm the diagnosis. However, this test is not always necessary to diagnose adrenal disease in ferrets. Symptoms and/or ultrasound alone are often sufficient.

Treatment

Surgical removal of the affected adrenal gland(s) is the only permanent treatment for this condition, and is highly recommended if a malignant tumor is suspected. For benign tumors, medical therapy to counteract the effects of excessive hormone production is generally very effective. The most widely used of these drugs is Deslorelin (Suprelorin F®). This is an implant that blocks the effects of excessive hormones on their target tissues. Implants can work for 8 months or longer. A similar type of drug is leuprolide (Lupron®) but this medication typically only lasts 1-3 months. Both of these drugs may block f the symptoms of the disease (such as hair loss), but does not arrest the growth of the adrenal tumor.

Home Care and Prevention

Home care consists of careful, educated observation more than any particular remedy. Because ferrets with adrenal disease can have trouble urinating, both urination and defecation need to be monitored. A “constipated” ferret may actually be trying to urinate and not move bowels.

Any ferret unable to urinate for more than 6-8 hours should be brought to see a veterinarian immediately (that same day!). Complete urinary tract obstruction is a life-threatening emergency.

Because we have not fully identified the cause of adrenal disease in ferrets, it would be difficult to try to prevent this. Some people feel that early neutering is to blame and maybe pet ferrets should be spayed or castrated as young adults, rather than very young juveniles. However, even many older-neutered ferrets are susceptible to developing the disease in time.

Adrenal disease refers to a hormone-producing tumor of the adrenal gland in the ferret. It is an extremely common condition, usually affecting ferrets over 3 years or age. The adrenal glands are a pair of organs located in the abdomen near the kidneys. In this disease, one or both adrenal glands become hyperactive and start to overproduce sex-steroid hormones, such as androgens and estrogens. The high level of hormones are then responsible for a myriad of symptoms including hair loss, signs of heat, anemia, and problems urinating. Some of these glands become tumors, which can be either benign or malignant. Both tumor types secrete excess hormone.

• The cause of this condition is unknown but may be related to the unique early development of the adrenals and gonads (ovaries and testes) in the very young ferret. It is thought that perhaps the neutering of juvenile ferrets for the pet trade may interrupt this early developmental pathway and the adrenal gland takes on some of the functions of the gonads. In the U.S., ferrets for the pet trade are typically neutered at less than 6 weeks of age. However, neutering ferrets as adults is gaining popularity, and we now know that even these ferrets can develop adrenal gland disease. So there is still much to learn about this very important disease.
• The hormones produced by this condition are responsible for most the problems of adrenal disease. These hormones include estrogen, testosterone, and other androgens (male hormones). The most common effect is hair loss that may be subtle at first, but progresses over time. This hair loss typically starts with the tail and moves forward over the rump and back. Most ferrets are excessively itchy. Some of the hormones result in enlargement of the male prostate gland, or remnant of prostatic tissue in females, and these ferrets have trouble urinating. Bone marrow suppression (anemia) can also result from long-term effects of estrogen. Because these hormones are sex-related, affected ferrets may develop signs of being “in heat”, such as a severely swollen and red vulva in females, or increased aggression in males.
• Complete urinary tract obstruction can occur with adrenal disease in male ferrets, and occasionally in females. The male hormones produced by the tumor result in prostate enlargement. The prostate then presses on the urethra, the small tube that exits the bladder. Early on, the ferret may strain to urinate, dribble urine, and lick the prepuce. But as the prostate grows, the urethra gets compressed and ultimately, these ferrets cannot urinate at all. This results in a life-threatening situation.
• The incidence of Adrenal disease increases with age, making the majority of affected ferrets over 3 years of age. However, younger ferrets can also develop the condition.
• The adrenal gland tumor is usually benign, meaning that it doesn’t spread to other body locations (“metastasis”). Malignant tumors can grow very quickly, and become large enough to compress other organs, such as the kidneys or intestinal tract. Ferrets with malignant disease may show symptoms one usually associates with cancer, such as weight loss, weakness and muscle wasting. Diagnosis can only be by biopsy and histopathology (microscopic diagnosis).

Diagnostic tests

• There is no simple, single test to confirm adrenal disease and many cases are diagnosed based on symptoms alone. Diagnostic testing is important, however, to evaluate overall health of the ferret, to check for concurrent diseases, to determine if the tumor is growing, and to see if the adrenal condition has led to other complications like anemia.
• Abdominal ultrasound (sonogram) is a relatively simple and safe test to evaluate the size of the adrenal glands and test for prostate enlargement. The image provided by the sonogram allows measurement of the adrenal glands to determine which gland is affected. Changes in the texture of the gland are sometimes good indicators of the possibility of malignancy, as can monitoring the glands over time for changes in size. It is important to know if the left or right gland is diseased, as surgery is more complicated if the right gland is involved. The normal adrenal gland in the ferret is about the size and shape of a lentil bean. Radiographs (X-ray’s) are not as helpful because they cannot give detail on such small structures. The sonogram also allows evaluation of all the other abdominal organs which lets us know if there are other complications.
• Complete blood count (CBC) and platelet count are essential to evaluate the activity of the bone marrow. The hormones produced by the tumor can suppress the production of blood cells from the bone marrow. This results in low red blood cells (anemia) and low platelet counts. Because platelets are essential for clotting in the body, ferrets with low counts develop bruises easily and are at a much higher risk of uncontrolled hemorrhaging. This is especially a concern if the ferret is to undergo surgical removal of the adrenal tumor. These individuals may require a blood transfusion before or after surgery. This test is very important, especially if the ferret has had symptoms for some time. Fortunately, bone marrow problems are not that common in ferrets with Adrenal Disease.
• Most veterinarians will also run a plasma chemistry panel to assess overall health of the ferret. Many ferrets with Adrenal Disease also have other common diseases, such as insulinoma. Testing is especially recommended if the ferret will undergo surgery.
• Plasma hormone testing can be performed to definitively diagnose the disease. However, this test does not differentiate which gland is affected (right or left), or indicate if the gland is malignant. In ferret showing the typical symptoms, the diagnosis is often based on ultrasound and/or symptoms alone.

Therapy

Because this condition is a hormone-producing tumor of the adrenal gland, the only definitive treatment is removal of the tumor or “adrenalectomy”. In most cases, only one adrenal gland is abnormal. Both can be affected, however, so it is important that each gland is examined carefully during surgery. The right adrenal gland is adhered to the vena cava, the largest vein in the abdomen. Right adrenal tumors can actually wrap around this vein or grow into it making surgical removal very tricky on this side. An accomplished surgeon is recommended for this procedure. The left adrenal gland is easier to approach and remove.

Medical therapy is used to block the actions of the adrenal hormones without actually affecting the tumor. While this type of therapy may reverse the symptoms of adrenal disease, it is does not stop the growth tumor. Therefore, if medical therapy is chosen, the gland should still be monitored for evidence of growth. Fortunately, most ferrets with Adrenal Disease have benign disease, and medical therapy alone is adequate. Medical treatment alone may also recommended for ferrets unable to withstand surgery because of age or other medical problems (heart disease, e.g.).

• Surgical removal of the affected adrenal gland(s) is the only definitive treatment for this condition. Once the tumor is removed, the ferret should be considered “cured”.
• In some cases of bilateral adrenalectomy (removal of both adrenals) hormone supplements have to be given to make up for the total lack of adrenal function. Prednisone (Pediapred®) replaces the cortisol made by the adrenal gland and florinef helps with electrolyte maintenance.
• Medical therapy to counteract the effects of excess hormone production is often very effective, especially in ferrets with benign disease. The most widely used of these drugs is Deslorelin (Suprelorin-F®). This is an implant that is injected under the skin, and typically lasts 8-12 months. A similar drug is leuprolide (Lupron®), an injection that has to be given every 1 to 4 months. These drug block the effects of excess hormone production. After administration, a swollen vulva will typically look normal within a week, hair will grow back within 6 weeks, and male ferrets will become less aggressive. The effect of these drugs on prostatic enlargement varies. A third treatment is a melatonin implant (Ferretonin®), which can also be effective for up to 3 months, especially in allowing regrowth of hair. None of these treatments, however, have any effect on the growth of the adrenal tumor, so monitoring for tumor growth is important if medical therapy is selected. Discuss these options carefully with your veterinarian.
• Emergency therapy sometimes must be given to ferrets with urinary tract obstruction. Relieving the urinary obstruction (“unblocking”) a ferret can be very difficult, due to the small size of the urethra. A small sterile tube is passed into the urethra, past the prostate, and into the bladder where the urine is then removed. Urinary catheterization is a temporary procedure necessary to save the ferret’s life. Treatment of the underlying Adrenal Disease is also necessary to allow the prostate tissue to shrink so that the ferret can urinate.