Addisons Disease (Hypoadrenocorticism)

Description & Cause
Addison's disease (Hypoadrenocorticism) is a severe or complete loss of function of both adrenal glands caused by a destruction of the adrenal cortex. The adrenal glands produce aldosterone, cortisol and corticosterone. Of the three hormones, the loss of aldosterone is most important clinically. Aldosterone us responsible for maintaining the equilibrium of sodium and potassium in the body.

The cause of Addison’s disease is suspected to be an autoimmune disease. The major cause of Addison's disease results from an auto-immune reaction in which the body's immune system erroneously makes antibodies against the cells of the adrenal cortex and slowly destroys them: The dog’s immune system attacks its own adrenal glands. That process takes months to years.


Symptoms/Clinical Signs
The slowly progressive loss of cortisol and aldosterone secretion usually produces a chronic, steadily worsening fatigue, a loss of appetite, weight loss, low blood pressure, vomiting, and diarrhea are common.

Generally, the disease begins very gradually and it is very easily missed in its early stages. Symptoms of Addison’s disease could have numerous other causes. These signs include floss of appetite, vomiting, weakness, hair loss, painful tummy, bloody stools, slow heart rate, trembling, low body temperature, collapse, diarrhea, dehydration. Many pets have heart irregularities and low blood pressure.

Addison’s disease is most commonly seen in young to middle aged dogs. No particular breed is affected more than another.


Diagnosis
A complete chemistry profile including blood count and sodium and potassium levels should be completed.Blood drawn from dogs with Addison’s disease is deficient in cortisol.


Treatment & Prognosis
Since all of the manifestations of Addison's disease are caused by the lack of cortisol and aldosterone, treatment consists of replacement steroid therapy. The prognosis is good and with the appropriate treatment and follow up care the affected dog should live a normal life expectancy.


Inheritance
Research suggests that the disease often is familial and an autosomal recessive pattern of inheritance has been suggested. In human the familial tendency frequently is seen when hypoadrenocorticism is associated with other endocrine deficiencies or autoimmune diseases such as hypothyroidism or even diabetes.