Addison's Disease

Addison’s Disease

               Addison’s disease—or, for the fancy medical term, hypoadrenocorticism—is a disease in dogs (and rarely cats) that can present with vague symptoms and can be life threatening if it goes undiagnosed.  What is Addison’s disease and how is it treated?

               Addison’s disease is a condition in which the adrenal glands which produce cortisol, aldosterone and other necessary hormones for the body do not function normally.  Loss of adrenal hormone production is typically caused by an immune disorder that destroys the adrenal gland and less commonly by cancer of the adrenal gland or by accidental administration of too much mitotane or trilostane which are drugs used to treat another adrenal disease called Cushing’s disease.  Addison’s disease may also occur if a dog has been on long term steroids which are suddenly withdrawn leading to loss of production of a hormone called ACTH which stimulates the adrenal glands to produce cortisol. This is why steroids like prednisone should be gradually reduced and not suddenly discontinued.  In addition, a small number of dogs have atypical Addison’s disease in which only the cortisol producing layer of the adrenal gland is destroyed, leaving the other parts of the gland intact and functioning normally.

               What happens if the adrenal gland can’t produce cortisol?  Cortisol is a necessary hormone for the body and is involved in the fight or flight response.  People and animals need cortisol to live and function normally. Too little cortisol results in an inability of the body to handle stress and illness.

               Addison’s disease is most common in young to middle aged female dogs and is more common in certain breeds such as Great Danes, Poodles, Rottweilers and Westies but any age or breed may be affected. It is though that the condition may be inherited.

               Symptoms include lethargy, weakness, shaking, increased drinking and urination, vomiting or diarrhea, decreased appetite, and weight loss.  Symptoms may come and go and thus are not always immediately recognized as Addison’s, and they are often present after a stressful event. Electrolyte disturbances may lead to dehydration, collapse and low blood pressure/shock in severe cases.

               Symptoms combined with electrolyte and other blood abnormalities are important for diagnosing Addison’s disease but definitive diagnosis is typically by a blood test called and ACTH stimulation test.  Cortisol levels are measured before and after a dose of synthetic cortisol stimulating hormone (cortrosyn) is given. If there is no increase in cortisol levels after the hormone is injected, the dog is diagnosed as having Addison’s disease. 

               Dogs in shock from an Addisonian crisis may need aggressive therapy with IV fluids and an injection of a potent but quick acting steroid like dexamethasone to combat shock, dehydration and elevated potassium levels.  Stable dogs diagnosed with Addison’s disease are treated with a monthly hormone injection (DOCP) or an oral medication called fludricortisone to replace mineralocorticoid hormones and also very low doses of prednisone to replace loss of cortisol.  This disease is not curable—dogs require lifelong treatment and monitoring. Periodic electrolyte checks are needed and many dogs may need a higher dose of prednisone during stressful events such as travel, surgery, etc.

 Addison’s disease has rather vague symptoms and can be quite serious if undiagnosed.  It is treatable with medication and dogs can live a normal life though they will be on medication all their lives.

               This blog brought to you by the Patton Veterinary Hospital serving Red Lion, York and the surrounding communities.

https://todaysveterinarypractice.com/endocrinology/canine-hypoadrenocorticism-overview-diagnosis-treatment/