Adrenal Disease

Overview 
The adrenal gland is a tiny organ that sits above each kidney.   In domestic ferrets, adrenal disease is one of the most common medical conditions.  Although the cause is unknown, it is most likely due to a combination of both genetic (breeding) and environmental components (dark-light periods, early spay/neuter, diet, etc.)  It occurs in both sexes and at any age, although it is more common in ferrets over 3 years of age.  
 
Diagnosis is by Clinical Signs
 

• Hair loss:  Often starts on the tail but can be anywhere on the body.  As the condition advances, the Ferret can become almost hairless.
• Skin changes:  dry, flaky, thin or wrinkled; itchiness, which can be severe. 
• Sexualized behavior in a previously neutered or spayed animal; caused by an increase in sex hormone production from the enlarged or malignant adrenal gland:
  • Males:   Aggression, often sudden with no prior history, and is associated with a high incidence of adrenal carcinoma; sexual behavior (marking, mounting) even if ferret is neutered.
  • Females:  Swollen vulva, which is 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. It can be life-threatening.    
• Lethargy:  very common sign; can be mild to severe and often comes on gradually.
• Muscle atrophy:   Most prominent over the dorsal pelvis and lateral chest.
• Enlargement of one or both adrenal glands on physical examination.

 
Treatments
 
Surgery:    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.  
• Other organs, specifically the pancreas, can be inspected for signs of tumors, such as pancreatic beta-cell tumors (“insulinomas”).    

 
Medical Treatment:

• Various drugs - leuprolide acetate (Lupron®) [injectable depot] and deslorelin acetate [Suprelorin F®] [implant] suppress, block or inhibit the production of the hormones being produced by the adrenal gland(s), hence halting the symptoms.  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. 
• 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.
• NB:  Melatonin (by any route) has not yet been proven to be safe or effective in treating adrenal hyperplasia or cancers in ferrets.  However, it does cause hair regrowth.        

Disease Course and Prognosis
 
Adrenal disease can be due to simple enlargement (“hyperplasia”) of the adrenal glands.  However about one in four (25%) ferrets have cancerous tumors, which can grow rapidly and cause urinary obstruction and other major health problems. If left untreated, 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.
 
In this condition, the affected adrenal gland produces an excess of sex steroids (estrogen, testosterone and their precursors) which result in the myriad of clinical signs present with this disease.
 
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 live normal lives with excellent quality of life.