Addison’s disease is a disorder of the
adrenal glands. The adrenal glands are small,
hat-shaped glands that sit on top of the kidneys,
high up inside the back of the abdominal wall.
The adrenal glands have two functions:
The inner area, called
the medulla, produces the hormone adrenaline,
and passes it into the bloodstream. Adrenaline
increases the action of the heart and speeds
up metabolism, preparing the body for shock.
The outer layer, called
the cortex, produces steroids. One of the
steroids it produces is cortisol, which
increases the supply of glucose in the blood.
Along with adrenaline, cortisol acts to
help the body cope with stress. Over-production
of cortisol can be harmful to the immune
system. Another steroid produced by the
cortex is aldosterone. Aldosterone helps
to maintain blood pressure by keeping sodium
(salt) levels up in the blood. Finally,
the adrenal cortex produces the male sex
hormone testosterone.
In people with Addison’s
disease, the adrenal cortex is destroyed,
leading to a deficiency or absence of the
hormones is produces.
Causes
Addison’s disease
is the result of the destruction of the
adrenal cortex. In about 70% of cases Addison’s
disease is an autoimmune condition. This
means that the destruction is caused when
the body’s own immune system attacks
the adrenal cortex as if it were a foreign
implant. The cortex becomes inflamed (swollen)
and the outer layer shrinks.
The other 30% of cases
are caused by infections such as tuberculosis,
tumours or other diseases of the glands.
Treatment
Replacing
the missing hormones through Hormone Replacement
Therapy (HRT) can relieve the symptoms of
Addison’s disease. Cortisol or prednisolone
steroids may be prescribed and must be taken
permanently, usually in a tablet form three
times a day.Fludrocortisone may also be
prescribed to replace the hormone aldosterone.
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Addison’s Disease
