Do you remember our good friend Cushing’s disease from last week? What would you say if I told you they had a relative named Addison’s. “you’re crazy Jamie”, “no, seriously, hypoadrenocorticism is called Addison’s disease”. *Mind blown*

Addison’s disease is the disease that comes from the under production of corticosteroids from the adrenal gland. Both glucocorticoids (involved with metabolism) and mineralocorticoids (involved with electrolyte maintenance/conservation/elimination) can be involved. Compared to the obvious signs of Cushing’s disease, Addison’s is usually quite vague presenting as animals that are just not quite right, listless, and sometimes having vomiting and diarrhea.

Due to the waxing and waning nature of the disease it is difficult to diagnose early. Quite often these patients present to us in an “Addisonian crisis”. Due to some stressor the animal becomes excessively weak and collapses. The body cannot properly respond due to its lack of steroid signals. The animal typically has low blood sugar due to the impaired glucose metabolism. Circulation is affected, potassium increases and heart rate decreases causing arrythmias and sometimes even death. These patients then require intravenous fluids with low potassium and injections of glucocorticoids, insulin and glucose to help them stabilize.

The only method to accurately diagnose this disorder is to do what is called an ACTH stimulation test. As discussed last week ACTH comes for the pituitary gland, it stimulates the adrenal glands to produce the corticosteroids. If there is Addison’s disease we won’t see a response (there won’t be any stimulation or production of steroids).

For the treatment of Addison’s we reach for medications. First is the mineralocorticoids either oral or injectable, help our pets maintain appropriate levels of potassium and sodium. Regular blood tests are required to make sure we have the appropriate level of control. Some animals may require glucocorticoid supplementation in times of stress, helping them maintain appropriate levels of glucose in their blood.

Sometimes we can see secondary Addison’s this is when pets have been on long term glucocorticoids such as prednisone. With external sources of the steroid the pituitary gland stops producing ACTH and with this the adrenal glands start to shrink. When patients stop these steroid cold turkey there are no longer the glucocorticoids in the system and the adrenal glands aren’t prepared to produce them either! This is why we taper people! Let the pituitary ready to start making ACTH and have the adrenal glands start up production again!!

Steroids are essential for the body to regulate itself, but sometimes the body forgets how to manage these signals appropriately. As you can see the system is complex and requires signals from different parts of the body. Fortunately we have the ability to help these animals with their chemical signals and although it is a lifelong treatment, many of these pets can live happy healthy lives!