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Addison's Disease
| Addison's disease is an endocrine or hormonal disorder that occurs in
all age groups and afflicts men and women equally. The disease is
characterized by weight loss, muscle weakness, fatigue, low blood pressure,
and sometimes darkening of the skin in both exposed and nonexposed parts of
the body. Addison's disease occurs when the adrenal glands do not produce
enough of the hormone cortisol and, in some cases, the hormone aldosterone.
The disease is also called adrenal insufficiency, or hypocortisolism.
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| Addison's disease affects about 1 in 100,000 people. Most cases are
caused by the gradual destruction of the adrenal cortex, the outer layer of
the adrenal glands, by the body's own immune system. About 70 percent of
reported cases of Addison's disease are caused by autoimmune disorders, in
which the immune system makes antibodies that attack the body's own tissues
or organs and slowly destroy them. Adrenal insufficiency occurs when at
least 90 percent of the adrenal cortex has been destroyed. As a result,
often both glucocorticoid (cortisol) and mineralocorticoid (aldostertone)
hormones are lacking. Sometimes only the adrenal gland is affected, as in
idiopathic adrenal insufficiency; sometimes other glands also are affected,
as in the polyendocrine deficiency syndrome. |
The symptoms of adrenal insufficiency usually begin gradually.
Characteristics of the disease are
- chronic, worsening fatigue
- muscle weakness
- loss of appetite
- weight loss
About 50 percent of the time, one will notice
Other symptoms include
- low blood pressure that falls further when standing, causing dizziness
or fainting
- skin changes in Addison's disease, with areas of hyperpigmentation, or
dark tanning, covering exposed and nonexposed parts of the body; this
darkening of the skin is most visible on scars; skin folds; pressure
points such as the elbows, knees, knuckles, and toes; lips; and mucous
membranes
Addison's disease can cause irritability and depression. Because of salt
loss, a craving for salty foods also is common. Hypoglycemia, or low blood
glucose, is more severe in children than in adults. In women, menstrual
periods may become irregular or stop.
Because the symptoms progress slowly, they are usually ignored until a
stressful event like an illness or an accident causes them to become worse.
This is called an addisonian crisis, or acute adrenal insufficiency. In most
cases, symptoms are severe enough that patients seek medical treatment
before a crisis occurs. However, in about 25 percent of patients, symptoms
first appear during an addisonian crisis.
Symptoms of an addisonian crisis include
- sudden penetrating pain in the lower back, abdomen, or legs
- severe vomiting and diarrhea
- dehydration
- low blood pressure
- loss of consciousness
Left untreated, an addisonian crisis can be fatal.
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| Treatment of Addison's disease involves replacing, or substituting, the
hormones that the adrenal glands are not making. Cortisol is replaced orally
with hydrocortisone tablets, a synthetic glucocorticoid, taken once or twice
a day. If aldosterone is also deficient, it is replaced with oral doses of a
mineralocorticoid called fludrocortisone acetate (Florinef), which is taken
once a day. Patients receiving aldosterone replacement therapy are usually
advised by a doctor to increase their salt intake. Because patients with
secondary adrenal insufficiency normally maintain aldosterone production,
they do not require aldosterone replacement therapy. The doses of each of
these medications are adjusted to meet the needs of individual patients.
During an addisonian crisis, low blood pressure, low blood glucose, and high
levels of potassium can be life threatening. Standard therapy involves
intravenous injections of hydrocortisone, saline (salt water), and dextrose
(sugar). This treatment usually brings rapid improvement. When the patient
can take fluids and medications by mouth, the amount of hydrocortisone is
decreased until a maintenance dose is achieved. If aldosterone is deficient,
maintenance therapy also includes oral doses of fludrocortisone acetate. |
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