Hormonal Diseases in Ferrets

ferret_-_reproductive_diseaseThere are four major diseases caused by hormonal disturbances in ferrets. Two of these diseases are covered in separate handouts: abnormally high levels of estrogen associated with persistent estrus in female ferrets (see handout "Reproductive Diseases in Ferrets"), and abnormally high levels of insulin associated with the pancreatic tumor called insulinoma (see handout "Insulinomas in Ferrets").

The remaining two major hormonal diseases to affecting ferrets are hyperadrenocorticism (adrenal gland disease) and diabetes mellitus. The first disease occurs in a large number of ferrets in North America, while the second is a rare, but an important problem.


Adrenal gland disease

"In ferrets, true Cushing's disease does not occur."

Disease associated with hyperactivity of the adrenal gland is common in ferrets in North America that are more than 3 - 4 years old. In dogs and cats, this is condition is called hyperadrenocorticism or Cushing's disease. It usually results from a pituitary gland tumor that produces a hormone causing the adrenal glands to produce excessive amounts of a steroid called cortisol. In ferrets, true Cushing's disease does not occur. Although hyperactive adrenal glands and adrenal gland tumors occur, the overactive glands do not produce excessive cortisol levels. Instead, there is an increased production of other hormones (especially various sex hormones like estradiol and progesterone). When ferrets have adrenal gland disease, the most common initial sign is hair loss on the flanks, with or without pruritus (itchiness). Affected female ferrets develop an enlarged vulva, while males often have problems with urination due to prostate enlargement. Hair loss and a swollen vulva are also common signs of persistent estrus, which can confuse the diagnosis in some cases. In some affected ferrets, an experienced veterinarian can palpate or feel the enlarged adrenal glands just in front of the kidneys. The spleen may also be enlarged in affected ferrets. 

In many cases, clinical signs and a thorough medical history can lead to a presumptive diagnosis of adrenal gland disease. Special sex hormone blood panels, ultrasound examination, response to medical therapy and surgery may confirm a definitive diagnosis.

These cases may be managed surgically or medically, depending on many factors such as which gland is affected (right or left - rarely both), the size of the adrenal gland, the availability of an experienced surgeon, the age of the ferret, the severity of clinical signs, the condition of the ferret, the presence of other diseases and, in some cases, financial considerations. Most cases are due to either an increase in size of the adrenal tissue or a benign adrenal tumor (adrenocortical adenoma). Some owners may choose not to treat at all, especially if the clinical signs are mild or perhaps are just limited to hair loss. Before making a decision regarding treatment, the pros and cons of the different treatment options should be discussed with a veterinarian familiar with ferrets.


Diabetes mellitus

"Diabetes mellitus, caused by an inadequate production of insulin, is rarely a primary problem. It often occurs secondary to removal of a pancreatic tumor."

Diabetes mellitus, caused by an inadequate production of insulin, is rarely a primary problem in ferrets. It often occurs secondary to removal of a pancreatic tumor known as an insulinoma, especially where numerous tumor nodules are found in the pancreas. A presumptive diagnosis of diabetes mellitus can be made based on persistently high blood and urine glucose levels, but definitive diagnosis requires measurement of a low blood insulin level in the face of high blood glucose levels. A ferret with diabetes mellitus can be treated with daily insulin injections. The ferret's urine should be monitored daily for the presence of glucose.


Other endocrine diseases

Interestingly, given the prevalence of estrogen-related and insulin-related endocrine disorders, to date there are no reports of thyroid-related endocrine disease in ferrets.

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