Ferret Adrenal Gland Disease

Authored by: Simon Starkey BVSc, PhD, D.ABVP(Avian)

The adrenal gland is responsible for many important functions. One key function is to produce adrenaline (epinephrine). Adrenaline helps the body respond to life-threatening situations and is the key driver of the fight or flight response. The glands also produce a critical hormone known as cortisol. Cortisol assists in regulating blood sugar and in metabolizing protein, fat and carbohydrates; it is also an immune regulator. Finally, the adrenal gland also produces relatively small amounts of reproductive hormones and their precursors.

What is Adrenal Disease?

When used to describe disease in ferrets, adrenal disease refers to hyperadrenocorticism. This big term simply means an overactive adrenal gland. An overactive adrenal gland usually produces too much cortisol in humans and dogs, and this condition is known as Cushing’s disease (or syndrome).

Ferrets get a Different Type of Adrenal Disease

The type of adrenal disease that ferrets get is different to that seen in people and dogs. In ferrets it is the reproductive hormones that are overproduced with overactive adrenal glands. The glands may be overactive due to hypertrophy (exaggerated growth), benign tumors or a malignant form of cancer. Without a surgical biopsy or gland removal and pathology, determining which of the three causes of adrenal disease a ferret has is difficult to impossible.

What are the Clinical Signs (Symptoms) of Adrenal Disease in Ferrets?

The increased amounts of circulating reproductive hormones lead to one or more of the following clinical signs in ferrets:

• Hair loss: This usually starts at the tail and often extends to involve the back, stomach and ultimately most of the pet’s body. Some ferrets initially lose fur only over the crown of their heads and look a bit like little Friar Tucks. These pets may go on to lose fur over their entire body as well.
• Itching: Approximately 30% of ferrets with adrenal disease will have itchy skin. They may have little scabs and scratches from itching so much. Some ferrets will also show a yellow discoloration of the skin accompanied by waxy-type exuded matter.
• Swelling of vulva: The majority (over 70%) of female ferrets with adrenal disease will have an enlarged vulva secondary to the increased reproductive hormones produced by overactive adrenal glands.
• Anemia: Female ferrets may develop anemia. Typically it takes a veterinarian to diagnose anemia, however you may suspect it if your ferret’s gums appear pale or if she is weaker than usual.
• Aggression: Aggression and increased sexual activity can be seen in some ferrets with adrenal disease. Typically, aggression is more common in males, but can be seen in female ferrets as well.
• Urinary problems: Because of increased testosterone levels, male ferrets can suffer from an enlarged prostate that can make urination difficult or impossible. This rapidly becomes a life-threatening situation and warrants emergency veterinary care.

How is Adrenal Disease Diagnosed?

While the symptoms of adrenal disease in ferrets are fairly characteristic, it is important to allow your veterinarian to perform additional diagnostic tests to help confirm the diagnosis and determine your pet’s overall health. In any middle aged or older ferret, whether there are signs of illness or not, your veterinarian will likely suggest a complete blood count (CBC) and chemistry panel. These tests don’t diagnose specific diseases; however, they give an overall picture of health by assessing liver and kidney health as well as monitoring for anemia and signs of infection. There are two tests available to specifically diagnose adrenal disease itself:

• Ferret adrenal panel:  Your veterinarian sends a blood sample to the laboratory for endocrine testing. Three common reproductive hormones are studied and if one or more are elevated, and then a diagnosis of adrenal disease can be made.
• Abdominal or adrenal ultrasound: This test is done by a skilled veterinarian, often a specialist in radiology.  The abdominal (stomach) ultrasound is more comprehensive than an adrenal ultrasound as all abdominal organs are evaluated (liver, kidney, spleen, bowel, bladder, and prostate) in addition to the adrenal glands. In an adrenal ultrasound only the adrenal glands are evaluated. The adrenal-only ultrasound will likely be slightly less expensive than a full abdominal ultrasound, but may or may not be an option depending upon your veterinarian’s policies.

How is Adrenal Disease Treated?

Broadly speaking there are two main ways to treat ferret adrenal disease: medical or surgical management. The decision as to which to use is made between the veterinarian and the pet owner by considering the following factors: The ferret’s age and sex, the disease and symptoms, presence of additional diseases, affected gland(s) (left, right or both), owner’s desire for cure versus control, risks of surgery, possible complications during and after surgery, and willingness to tolerate possible recurrence or disease of opposite gland if surgery is performed.

• Surgery: Generally speaking the prognosis for left-sided adrenal gland removal is good and the chances of medium to long-term cure are good. Right-sided disease is complicated by the close proximity of the right adrenal gland to the largest vein in the body (the vena cava) and the liver. As such, right-sided or bilateral (both sides) adrenal disease carries a larger risk of complications as well as a reduced likelihood of cure. If the right gland is affected, the surgeon may only be able to partially remove the gland. This may slow the progress of the disease, but is unlikely to cure.
• Medical management: There are several types of medical management available. The medication offered to you will likely vary with your veterinarian’s experience and comfort level with one or more of the available treatment options. Medical management will help reduce and potentially eliminate some of the potentially life-threatening secondary symptoms of adrenal disease (such as anemia or urinary blockage) but it is generally not believed to be effective in slowing or stopping tumor growth in those ferrets affected by adrenal gland cancer.

Lupron (leuprolide): Lupron has been a mainstay of medical management for several years. This medication is generally effective in controlling clinical signs when given to ferrets by injection once a month. Lupron helps to reduce the hormone-induced aspects of adrenal disease, such as fur loss, estrogen-induced anemia and prostate disease. Lupron is essentially a synthetic hormone, and over time the ferret’s body may recognize this substance as foreign and create antibodies against it, thereby reducing its effectiveness.

Deslorelin: This drug is similar to Lupron, although it is available in a longer-term implant (8-12 months).

Melatonin: The use of oral melatonin has been studied in ferrets and it has proven effective in treating the clinical signs and hormonal changes seen with this disease. One problem with its use, however, is the lack of regulation of melatonin manufacture in the U.S. As such it can be difficult to be certain that the ferret is gaining the benefit it should from this drug. As an alternative, a melatonin implant is available to veterinarians in the U.S. This product is being actively researched and initial reports are very promising as to this product’s ability to improve fur loss and the hormonal status of ferrets with adrenal disease.

Treating adrenal disease requires a commitment on the owner’s behalf and teamwork between the owner and their veterinarian.