Hypoadrenocorticism (Addison’s Disease)
WHAT IS ADDISON’S DISEASE?
Addison’s disease is a fairly common hormonal disease that affects mainly dogs. It involves failure of the adrenal glands, small hormone-secreting glands located near the kidneys. It is not known exactly why the adrenal glands stop functioning, but it is possible that they are destroyed by the immune system. The hormones that the adrenal glands normally secrete are steroids (also called glucocorticoids) and aldosterone (also called a mineralocorticoid). These hormones are essential for life. Therefore, if Addison’s disease is not treated, it can be fatal. However, the good news is that it can be treated, by simply giving your dog the hormones that the adrenal glands should normally be making. Your dog is in good company: John Fitzgerald Kennedy also had Addison’s disease, and it did not kill him!
HOW WOULD I KNOW MY DOG HAS ADDISON’S DISEASE?
Classic chronic clinical signs are gradual loss of appetite, weight loss, perhaps some vomiting or diarrhea, and maybe some degree of lethargy. These signs can be mild and chronic or acute, and not all of these signs must be present to confirm a diagnosis. Sometimes the initial clinical signs are not noticeable, and the dog develops a clinical crisis, which involves hospitalization and intravenous fluid care, as well as hormone supplementation.
HOW IS ADDISON’S DISEASE DIAGNOSED?
Addison’s disease is diagnosed based on clinical signs and some testing, which will depend on your dog’s specific clinical signs. Ultimately, an adrenocorticotropic hormone (ACTH) stimulation test, which is a 1-hour blood test, must be performed to confirm a diagnosis. Other tests will likely be performed, to make sure this is the only problem that your dog has.
HOW IS ADDISON’S DISEASE TREATED?
Long-term treatment involves supplementing the hormones that would otherwise be produced by the adrenal glands. We usually treat with desoxycorticosterone pivalate (DOCP) to supplement for the missing aldosterone, and prednisone for the missing glucocorticoids.
DOCP is given as an injection under the skin, and your veterinarian can teach you how to give it at home. If you prefer, you can come into the clinic to have one of the nurses or veterinarians give your dog the injection. Initially we give the injection every 25 days, but we like to perform a blood test (measure sodium and potassium) at days 14 and 25 and then every 5 days thereafter, to determine if we can prolong the interval between injections and also to determine if we can give a smaller dose of DOCP in the future. This testing may seem costly at first, but it saves resources in the long run.
Prednisone is given orally, on a daily basis, and the dose of this medication will also be adjusted as time goes by. Prednisone can never be discontinued abruptly. It is paramount that you notice when your supply is diminishing and call for a refill in a timely fashion. Abrupt discontinuation of prednisone can be fatal.
Your veterinarian may also give you some prednisone for special instances in which you think your dog may experience more stress than usual. Such instances may include travel, kenneling, company, or large family gatherings. In such instances, your veterinarian may instruct you to give more than the usual dose of prednisone.
Another treatment option is fludrocortisone, which includes both glucocorticoids and a mineralocorticoid.
NOW THAT MY DOG HAS BEEN DIAGNOSED WITH ADDISON’S DISEASE, IS THERE ANYTHING IN PARTICULAR I SHOULD BE WATCHING FOR?
Yes! Please let your veterinarian know if you notice decreased appetite, vomiting, diarrhea, weight loss, or lethargy. These signs may suggest that an increase in prednisone is warranted. Please also notify your veterinarian if you notice increased drinking, increased appetite, or panting. These signs may suggest that the dose of prednisone has to be decreased. Please be mindful of any stressful situations that may arise, and discuss with your veterinarian the need to increase the dose of prednisone for a day or two during such events. Please avoid deviating in any way from the treatment protocol, without discussing this first with your veterinarian. Finally, be sure never to run out of prednisone, because abrupt discontinuation of this drug can be life-threatening.
WILL MY DOG BE OK?
Yes! Close and constant communication with your veterinarian, careful adherence to the treatment protocol, and regular checkups will help your dog have a happy and long life, with successfully treated Addison’s disease.