Adrenal Disease

Overview 
In domestic ferrets adrenal disease is one of the most common medical conditions. The adrenal gland is a tiny organ that sits above each kidney. Adrenal tissue can grow ("hyperplasia") or may present as tumors. Negative effects include 1)  production of increased "sex" hormones; and 2) crowding and blockage of other organs resulting in abnormal function as a result of increasing size of the tumors.  

What is adrenal disease in a ferret?
Although the cause remains unknown, it is most likely due to a combination of both genetic (breeding) and environmental components (dark-light periods, early spay/neuter, diet, etc.)

Adrenal disease occurs in both sexes and at any age, although it is more common in ferrets over 3 years of age.  

Adrenal gland disease is often present with other common endocrine (hormonal) tumors in the ferret, such as pancreatic beta cell tumors that cause low blood sugar ("hypoglycemia").
 
Diagnosis
Diagnosis is made by physical examination, radiologic tests that show enlargement of one or both adrenal glands, but also by the following physical signs:

• Hair loss: often starts on the tail, but can appear anywhere on the body.  As the condition advances, the ferret can become almost hairless [see photo, below].
• Skin changes:  dry, flaky, thin or wrinkled; itchiness, which can be severe. 
• Sexualized behavior in a previously neutered or spayed animal: this is due to increased sex hormone production from the enlarged adrenal gland, and presents differently depending on the sex of the ferret:
  • Males: sexual behaviors (marking, mounting) in a neutered male ferret;   aggression, which can often occur suddenly with no prior history, is associated with a high incidence of adrenal carcinoma.
  • Females: swollen vulva [see photo, below] due to excess of female hormones; 50% of female ferrets present with this sign, which is often accompanied by vaginal discharge and infection.   
• Straining to urinate:  seen in males due to blockage of the urinary tract caused by enlargement of the prostate gland as a result of increased male sex hormones. Requires immediate intervention, as it can be life-threatening.
• Lethargy: lack of energy is a very common sign; can be mild to severe and often comes on gradually.
• Muscle atrophy: decrease in muscle mass, most prominent over the back and pelvis and lateral (sides) chest.   

Hair loss due to adrenal disease in a ferret

Enlarged vulva in a female ferret with adrenal disease

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What are the treatments for adrenal disease? 

Surgery:    surgical removal of the affected adrenal gland(s).  
Reasons for doing surgery: 

• Potential cure of the disease. (Medical therapy can reverse symptoms, but does not change the tumor).
• 1 in 4 tumors are malignant.
• Relief of blockage from space-occupying tumors:  of critical importantance, such as when a male ferret can no longer urinate.  
• Other organs, specifically the pancreas, can be inspected for signs of tumors, such as pancreatic beta-cell tumors (“insulinomas”).    

 
Medical treatment:  nonsurgical treatments, such as drugs or other types of products
Reasons for using medical treatments:

• Ferret is not a surgical candidate (usually due to advanced age or other illnesses, such as heart disease, etc.)
• Ferret has had prior surgery, but the signs have returned.

Drugs and other products:

• Various drugs - leuprolide acetate (Lupron®) [injectable depot], which lasts from 2-4 months, and deslorelin acetate (Suprelorin® F) [implant] which can last up to a year.  These drugs suppress, block or inhibit the production of the hormones being produced by the adrenal gland(s), which can halt the physicial signs.  Most drugs do not reduce the size of the gland or tumor. Ferrets may respond to one drug better than another.  Therefore, if a drug is not working, another should be tried. 
  
• Other products - melatonin (by any route) is a product that is naturally made by the body.  This product has not yet been proven to be safe or effective in treating adrenal hyperplasia or cancers in ferrets.  It can, however, result in hair regrowth.        

Disease Course and Prognosis
The condition is a chronic, debilitating disease, which can have a negative impact on the ferret’s quality of life and even its life span. Adrenal disease can be due to simple enlargement (“hyperplasia”) of the adrenal glands.  However about 25% (1 in 4) ferrets are found to have cancerous tumors that can grow rapidly. If left untreated, the these tumors can result in blockage of the urinary tract, which can lead to severe pain and death. 

In recent years great advances have been made in the early diagnosis and treatment.  Although still a very common medical condition, most adrenal disease can be controlled with medical treatment.  Ferrets that are properly maintained on medical treatment can often live normal lives with excellent quality of life.

For further reading: 
V. Bakthavatchalu1, S. Muthupalani1, R. P. Marini1, and J. G. Fox. (Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, USA) Endocrinopathy and aging in ferrets. Vet Pathol. 2016 March ; 53(2): 349–365. doi:10.1177/0300985815623621

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