What is Addison's disease?
Addison's disease occurs when the two adrenal glands in the body are damaged
and are no longer able to produce certain hormones, which are essential for
the maintenance of life. The adrenal glands are situated on top of each kidney.
'The adrenal glands sit like a small cap on the upper pole of each kidney.'
They produce three different groups of hormones known as corticosteroids. One
group consists of the androgens and estrogens, which affect sexual development
and reproduction. The glucocorticoids maintain glucose regulation, suppress
the body's antibody response and provide for the response to stress through
the secretion of cortisol. The third group are known as mineralocorticoids and
they regulate sodium and potassium balance in the body.
What causes it?
Addison's disease is quite rare, but by far the most common cause of it is
an autoimmune disorder in which the body's own immune system attacks and destroys
the adrenal glands. Sudden withdrawal of long term steroid therapy, removal
or injury of the adrenal glands or destruction of the pituitary gland may also
cause it. The disease can also be triggered by factors such as infection, cancer
or bleeding into the adrenal glands.
What are the symptoms?
In most cases, the symptoms of Addison's disease come on gradually. Any or
all of the following symptoms may be present:
- a general feeling of weakness and fatigue.
- darkening of the skin.
- unexplained weight loss.
- low blood pressure, leading to frequent dizzy spells.
- an imbalance of salt in the body, leading to irregular beating of the heart.
- pains in the muscles and joints.
- nausea, vomiting and diarrhoea.
- pain in the flank.
If the condition comes on abruptly the patient's general condition can deteriorate
rapidly leading to very low blood pressure, dehydration, high fever, profound
weakness, excessive sweating ultimately leading on to loss of consciousness
and death. This scenario is called an Addisonian Crisis and must be dealt with
as an extreme emergency.
How is it diagnosed?
Addison's disease may be suspected on the basis of the symptoms and physical
findings however the following laboratory findings are diagnostic of the condition:
- cortisol level is low.
- fasting blood sugar may be low.
- serum potassium is elevated.
- serum sodium is decreased.
How is it treated?
Addison's disease is usually treated by the replacement of the missing adrenal
hormones. In the short-term this may involve the use of IV fluids, IV hormones
and other medications to stabilise the patient's general condition. Once the
patient is stable hormone pills alone can be used to treat the disease. Life
long hormone replacement will be required and regular blood tests will be necessary
to monitor salt and hormone levels in the body.
All patients with Addison's disease are instructed in the adjustment of their
drug treatment if they develop infection or are subjected to extreme stress.
Such situations could trigger an Addisonian crisis and lead to sudden collapse
if not anticipated. All patients with the condition are advised to wear a medic
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