Introduction
Addison’s disease, also known as hypoadrenocorticism, is a condition that develops when a deficiency in the body’s adrenocortical hormones occurs. Addison’s disease is classified into primary or secondary conditions.
Causes of Addison's Disease
The cause of a primary Addison’s disease condition is not always known, but it is believed to be related to a possibly inherited immune condition in addition to cancerous tumors, destruction of the adrenal gland, sudden hemorrhage, or when a blood blockage develops in the body. Secondary Addison’s disease occurs when steroid medication therapies are suddenly withdrawn, or by decreased ACTH production from the pituitary gland (Also known as "atypical Addison’s disease" because there is just a glucocorticoid deficiency but not a mineralocorticoid deficiency).
Symptoms of Addison’s Disease
The clinical signs of Addison’s disease can vary, but they usually result in collapse, increased drinking/urination, slow weight loss, poor skin and coat conditions, and a reduced appetite which often results in anorexia. Animals with Addison’s disease often suffer from diarrheal gastroenteritis, vomiting, and dehydration. In advanced cases the disease can mimic symptoms of shock including low body temperature, shaking, and slow heartbeat.
Diagnosing Addison's Disease
The diagnosis of Addison’s disease involves reviewing the animal’s recent medical history and conducting the following test:
- ACTH Stimulation Test
- HDDS or ultrasound to differentiate primary from secondary
- LDDS (low-dose dexamethasone suppression)
- Complete blood tests (Low sodium and high potassium; Na:K ratio less than 27 is suspect)
Treating Addison's Disease
The treatment of dogs with Addison's disease ultimately begins with addressing whether the animal is suffering from primary or secondary Addison’s Disease. However, because many dogs diagnosed with Addison's disease are already severely ill, the first goal is stabilizing the animal. Secondary sufferers are placed back on their steroid medications and slowly withdrawn from them at a future date. Primary sufferers are treated using lifelong corticoid replacement therapy most often in the form of an oral medication known as fludrocortisones or Florinef, or as an injection known as DOCP.
Outlook for Dogs with Addison's Disease
The prognosis for primary and secondary Addison’s disease is usually good as long as the disease has been diagnosed early and is managed properly.