Addison's disease, also called hypoadrenocorticism, is a deficiency in your dog’s ability to produce certain hormones normally produced by the adrenal glands. The two main hormones produced by your dog’s adrenal glands, which are located next to your dog’s kidneys, are glucocorticoids and mineralcorticoids. The glucocorticoids help your dog metabolize nutrients and deal with stressful situations. The mineralocorticoids assist your dog in regulating essential electrolytes such as sodium and potassium.

Addison’s disease is classified as either primary Addison’s disease or secondary Addison’s disease. Primary Addison’s disease is when your dog’s adrenal gland itself is diseased and cannot produce sufficient hormone levels. Secondary Addison’s disease occurs when your dog’s adrenocorticotropic hormone, a hormone that stimulates the adrenal gland to produce hormones, does not function properly.

Addison’s disease is often first diagnosed in young dogs, but the condition can begin later in your dog’s life as well. Addison’s disease can also occur in any breed or mix although certain breeds including Labrador Retrievers and Poodles seem to be more commonly impacted.

Initial symptoms include lethargy, vomiting and/or diarrhea. Next, your dog may have muscle weakness, abdominal pain, increased thirst, increased urination and bloody stool. Your dog may also develop an Addisonian crisis which is when your dog collapses in shock because his body is not capable of regulating his electrolytes. Potassium levels will rise and cause your dog to have a potentially life-threatening irregular heart rhythm.