• SYSTEM(S) EFFECTED:
    		•  Endocrine
  • CAUSE(S):
    		• Dysfunction of the adrenal glands
  • DIAGNOSTICS:
    		• Minimal diagnostic tests
  • TREATMENT:
    		• Lifetime drug therapy
  • PREVENTION:
    		• No

GENERAL DESCRIPTION

Addison’s disease occurs when function of the adrenal glands are compromised or decreased.  This is considered to be a disease almost exclusively effecting dogs, and is most prevalent in females.  Addison’s disease is considered to be extremely rare in cats.

SOURCE & CAUSE(S)

The adrenal glands are located next to the kidneys and their job is to produce hormones which are responsible for regulating the "fight or flight" response and hormones which are responsible for keeping electrolytes such as potassium and sodium balanced.  Hypoadrenocorticism is the medical term for Addison’s disease, "hypo" meaning low, "adreno"-referring to adrenal gland and "cortico"- referring to the steroid cortisol which is produced from the adrenal gland and is involved in the stress regulation of "fight or flight" syndrome.  Aldosterone is the other hormone produced from these glands that is involved in the balance of electrolytes.  When there is a decreased production of these two hormones, cortisol and aldosterone, this is referred to as Addisons disease. 

The primary reason or cause for the dysfunction of the adrenal glands is due to some injury to the gland tissue by the immune system.  Infection, medications, cancer, and diseases of the pituitary gland are also known causes for Addisons disease.  If your dog has been treated with a course of steroids for a long period of time and the steroids are stopped abruptly, this has been known to cause a syndrome known as an Addisonian crisis thus leading to Addison’s disease.

SIGNS & SYMPTOMS

  • Vomiting
  • Diarrhea
  • Low-energy
  • Weight loss
  • Lack of appetite
  • Drinking and urinating a lot (polydipsia)
  • Nervousness, not reacting to stress appropriately
  • Muscle weakness, may wobble when walking.
NOTE: These can appear rather mild at first and then resolve and repeat later.  If your dog is having an Addisonian crisis these symptoms will be much more pronounced. There is a risk of shock developing and you may see your dog collapse. THIS IS AN EMERGENCY.  Go to the vet ASAP.

DIAGNOSIS & TESTS

 Diagnosis begins with a complete history and a physical exam.  Your veterinarian will most likely to the following:

  • CBC/Chemistry Panel - These blood tests will evaluate various internal organ functions, including the heart, liver, kidneys, pancreas, metabolism, and electrolyte balance. The CBC is a measure the amount and different kinds of red and white blood cells are present in the body.
  • ACTH Stimulation Test - This will test the adrenal glands function and is the key test when making this diagnosis.  This will require a day stay in the hospital for your dog.

TREATMENT & MANAGEMENT

Treatment options will depend on the state of the illness at the time.  If symptoms are severe and appeared rapidly this is considered an Addisonian crisis and will require emergency treatment.  If the symptoms present mild and/or chronic, the treatment will consist of oral replacement of the deficient hormones.

Long-term management of the disease is done through periodic retesting of the hormone levels and periodic adjustment of the replacement therapies.  

PREVENTION & HELPFUL TIPS

There is no tried-and-true way to prevent the onset of Addison’s disease by means of the naturally occurring form of the disease.  However, if your dog is being treated for another condition by way of steroids, DO NOT stop the medication abruptly. This is one way to trigger the onset of an Addisonian crisis.

  • ALWAYS give your dog his medication(s) exactly as they are prescribed.
  • Report any instances of vomiting, diarrhea or change in appetite and drinking behavior to your veterinarian.

Written by: PetsMD Veterinary Editorial Staff