What is Addison's Disease?

Please understand the following information is offered as a courtesy and is not intended to provide a diagnosis or medical recommendation for your pet.

What is Addison's Disease?
Addison's Disease is a disease in which the adrenal glands fail to produce certain hormones. The correct medical term for this disease is hypoadrenocorticism. Normally, the adrenal glands produce several vital hormones that regulate a variety of body functions and are necessary to sustain life. These hormones are often divided into two groups: glucocorticoids and mineralocorticoids. Glucocorticoids are part of the body’s normal “stress” response and will increase in times of stress or illness to allow the body to better respond to whatever challenge has arisen. Mineralocorticoids are hormones that assist in the body’s regulation of water and salt. Addison’s disease usually develops when the adrenal glands are unable to produce sufficient glucocorticoids and mineralocorticoids.

What are the clinical signs?
The clinical signs of Addison’s Disease can be quite variable as the hormone functions are quite variable. With the loss of glucocortoid function, dogs are unable to respond to stressful situations and become ill unexpectedly during boarding or other stressful times. Vomiting and diarrhea are common clinical signs of Addison’s Disease. With the loss of mineralocorticoid function, dogs cannot maintain their water and salt balance. This can cause an increase in water intake and urination and an inability to prevent dehydration and maintain electrolyte balance. As you can see, the combination of effects can make this disease quite severe, possibly resulting in seizures, heart arrhythmias, and even death.

How is it diagnosed?
The first step to diagnosis is suspicion based on history and clinical signs. There are a variety of changes that may be seen on our routine bloodwork (complete blood count and biochemical profile) and these changes will guide our immediate treatment of your dog. Confirmation of Addison’s Disease is by a blood test called ACTH Stimulation test. The ACTH Stimulation Test is performed by administering a synthetic hormone with mimics the body’s own hormone that causes the adrenal gland to release cortisol (a glucocorticoid). The levels of cortisol before and after this injection are compared; dogs with Addison’s disease are unable to respond to this injection just as they are unable to respond to their own hormone. If indicated, the body’s ability to release mineralocorticoid can be tested in a similar manner.

What are the treatment options?
Often the clinical signs of Addison’s Disease are severe enough to require hospitalization to allow treatment with intravenous fluids and other supportive care. Specific treatment for Addison’s Disease is usually composed of two aspects: replacement of the glucocorticoid and mineralocorticoid activity. Prednisone, an oral medication, is the most common glucocorticoid prescribed. Prednisone is inexpensive and usually given once daily. You will be advised to increase the dose of glucocorticoid (prednisone) in times of illness or stress (such as boarding), because the body usually would do the same. There are two commonly prescribed medications used to replace the mineralocorticoid activity for our Addisonian patients. Florinef is an oral tablet given once or twice daily. Florinef is unique in that it has both mineralocorticoid and glucocortoid activity. This can be good in that 50% of dogs can be maintained on Florinef without additional prednisone during non-stressful times. Of course, some dogs require both Florinef and prednisone to stay healthy. The other commonly used mineralocorticoid is an injectable medication, DOCP. DOCP is long-acting; a single injection will last approximately 25 days and often owners learn how to administer this medication themselves. DOCP is a pure mineralocorticoid and therefore prednisone must still be given daily. While Addison’s Disease requires life-long medication, we should be able to eliminate all clinical signs and help your dog live a normal life.