- The adrenal cortex produces hormones known as corticosteroids, which enable a dog's body to handle stress. Glucocorticoids help prepare a dog's metabolism for burning fuels, while mineralocorticoids control sodium and potassium levels. Stressful situations require high sodium and low potassium levels so that a dog's body can store extra blood if needed. A lack of these hormones results in Addison's disease. The cause of this condition can rarely be determined, unless the dog takes a medication that interferes with the balance of sodium and potassium in the adrenal glands.
- The first symptoms of Addison's disease can include listlessness, diarrhea and vomiting, although these signs do not show up until about 90 percent of the adrenal cortex is non-functional. Regurgitating undigested food due to a problem with the esophagus can also be a sign of this disease. When left untreated, "Addisonian crisis" occurs, resulting in physiological collapse because the dog's body is unable to handle stress. A dog might experience a slow, irregular heart rate due to high potassium levels and dangerously low blood sugar. According to the Mar Vista Animal Medical Center, about 30 percent of dogs are diagnosed with this disease during an Addisonian crisis. Addison's disease occurs most often in female dogs between four to five years old, although it can be found in dogs of any age. Breeds such as standard poodles and bearded collies face a higher risk because of a genetic predisposition for this disease.
- An ACTH stimulation test involves administering a dose of the hormone known as ACTH that releases corticosteroids during stress. A lack of response in corticosteroid levels results in an Addison's disease diagnosis. Dogs that have collapsed receive general treatment for shock, which involves administering fluids and glucocorticoids. In these cases, a dog might recover before the true cause of the collapse is fully determined. Conditions such as acute renal failure or a pancreatic tumor have similar symptoms to an Addisonian crisis, including elevated potassium levels and unstable blood sugar levels, which can make an accurate diagnosis difficult to determine while a dog is in shock.
- Treatment involves replacing mineralocorticoids through the use of an oral or injected medication. Florinef can be taken orally twice a day, accompanied by weekly blood tests to measure potassium and sodium levels. When these levels remain stable, the tests are given two to four times a year. Forinef also provides glucocorticoids, making supplements unnecessary. Florinef dosage can often require an increase over time to keep Addison's disease under control. As an alternative to Florinef, an injected medication known as DOCP can be given every 25 days. Blood tests monitor sodium and potassium levels before injections are given, and can gradually be reduced to one or two times a year. Some dogs taking DOCP also need a glucocorticoid supplement, such as prednisone.
- Some dogs experience a condition known as atypical Addison's disease. When the pituitary gland fails to secrete ACTH, the areas of the adrenal cortex that produce glucocorticoids waste away, while the area that produces mineralocorticoids remains intact and fully functional. A normal level of mineralocorticoids and a lack of glucocorticoids results in an inability to control blood sugar but carries no risk of suffering an Addisonian crisis. When a diagnosis of atypical Addison's disease is made based on a low response to an ACTH stimulation test, treatment requires a glucocorticoid supplement. Dogs with this condition often end up with typical Addison's disease, including a lack of mineralocorticoids.
