Addison’s Disease (hypoadrenocorticism)

Addison’s Disease is properly called hypoadrenocorticism, that is an under active adrenal gland. The adrenal glands of the body have serve multiple functions. One of them is the production and release of “adrenalin” and cortisol. These compounds cause changes in the body which protect the body from stress.
Another major function of the adrenal glands is the production of mineralocorticoids. These compounds regulate the body’s sodium and potassium levels and the body’s water balance. The cause of Addison’s is unknown but it is thought to be immune-mediated. It is primarily seen in dogs, and is most commonly seen in young (average 4 years), female dogs and is almost never in cats.

Clinical signs of Addison’s include weakness, diarrhea, polyuria and polydipsia. The most common finding on physical exam that would raise suspicion of Addisons in a dog with clinical signs is bradycardia, a slow heart rate. Affected dogs can have an Addisonian crisis which comes on without warning and requires immediate medical intervention. These dogs may have diarrhea, then will fade rapidly, becoming weaker and more despondent in only a few hours. The diagnosis of Addison’s is confirmed by finding elevated sodium and potassium blood levels and no response to an ACTH stimulation test. (This test measures the adrenal gland’s response to simulation by ACTH. It is also used to diagnose and monitor hyperadrenocorticism)

Addison’s Disease is treated by one of two methods:
1. Fludrocortisone given orally
a. Dosage must be daily
b. Dosage range is varies tremendously making it difficult to manage
c. Dogs can be resistant to the drug.
2. DOCP Injections
a. Dosage once every 25 days
b. Dosage very exact, does not vary
c. Cost only varies with weight of dog.

These two compounds replace the mineralocorticoids which regulate the electrolyte and water balance of the body. In addition, glucocorticoid supplementation is also begun with Prednisone.

Addison’s is a serious, life-threatening condition whjch requires treatment. The clinical signs of polyuria, polydipsia, depression and weakness, with or without diarrhea is not very specific for any one disease condition. The successful treatment and management of Addison’s Disease is dependent on close communication between the pet owner and the veterinarian.