Addison’s Disease in Dogs

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

Signs & Symptoms of Addison’s Disease (Hypoadrenocorticism)

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, 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 veterinarian immediately.

Causes of Addison’s Disease

The adrenal glands are located next to the kidneys and their job is to produce hormones that are responsible for regulating the "fight or flight" response, and hormones that are responsible for keeping electrolytes, such as potassium and sodium, balanced. Hypoadrenocorticism is the medical term for Addison’s disease;

hypo – low + adreno – adrenal gland + cortico – cortisol

Cortisol is a steroid that 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 cortisol and aldosterone, this is referred to as Addison’s disease.

The primary 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 known causes for Addison’s 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 called an Addisonian crisis, thus leading to Addison’s disease.

Diagnosis of Addison’s Disease

Diagnosis begins with a complete history and a physical exam. Your veterinarian will most likely do 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 that are present in the body.
ACTH Stimulation Test - This will test the adrenal glands function, and is the key test when making a diagnosis of Addison’s disease. This will require a day stay in the hospital for your dog.

Treatment for Addison’s Disease

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 of Addison’s Disease

There is no tried-and-true way to prevent the onset of the naturally occurring form of Addison’s 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.