Adrenal Diseases - Addison's Disease
The Facts You Need To Know
On This Page:
What is Addison's Disease?
What Causes Addison's Disease?
What are the symptoms of Addison's Disease?
How is Addison's Disease diagnosed?
How is Addison's Disease treated?
Why should Addisonians consult an Endocrinologist?
Are there related diseases?
Why is Addison's considered a rare disorder?
How normal is an Addisonian's life?
What
is Addison's Disease ?
Addison's disease is a severe or total
deficiency of the hormones made in the adrenal cortex, caused by the
destruction of the cortex.
There are normally two adrenal glands, located one above each
kidney. The adrenal glands are really two endocrine (ductless or hormone
producing) glands in one.
The inner part of the adrenal gland (called the
medulla) produces epinephrine (also called adrenaline) which is produced at
times of stress and helps the body respond to "fight or flight" situations
by raising the pulse rate, adjusting blood flow, and raising blood sugar.
The absence of the adrenal medulla and epinephrine does not cause
disease.
The outer portion of the adrenal gland, the cortex, is
more critical. The adrenal cortex makes two important steroid hormones, cortisol and aldosterone.
Cortisol mobilizes nutrients, modifies the body's
response to inflammation, stimulates the liver to raise the blood sugar, and
also helps to control the amount of water in the body.
Aldosterone regulates
salt and water levels which affects blood volume and blood pressure.
Cortisol production is regulated by another hormone, adrenocorticotrophic
hormone (ACTH), made in the pituitary gland which is located just below the
brain.
Classical Addison's disease results from a loss of both cortisol and
aldosterone secretion due to the near total or total destruction of both
adrenal glands. This condition is also called primary adrenal insufficiency.
If ACTH is deficient, there will not be enough cortisol produced, although
aldosterone may remain adequate. This is secondary adrenal insufficiency,
which is distinctly different, but similar to Addison's disease, since both
include a loss of cortisol secretion.
What
Causes Addison's Disease?
When Dr. Thomas Addison's first described this disease in London in 1855, the
most common cause was tuberculosis. This remained the leading cause until
the middle of the twentieth century when antibiotics progressively reduced
TB's incidence.
Since then, the major cause of Addison's disease results
from an autoimmune reaction in which the body's immune system erroneously
makes antibodies against the cells of the adrenal cortex and slowly destroys
them. That process takes months to years.
There are also several less common
causes of Addison's disease: other chronic infections besides tuberculosis,
especially certain fungal infections; invasion of the adrenal by cancer
cells that have spread from another part of the body, especially the breast; CMV virus in association with AIDS; hemorrhage into the adrenals
during shock (rare); and the surgical removal of both adrenals.
What are the symptoms of Addison's Disease?
The slowly progressive loss of cortisol and aldosterone
secretion usually produces a chronic, steadily worsening fatigue, a loss of
appetite, and some weight loss. Blood pressure is low and falls further when
a person is standing, producing lightheadedness. Nausea, sometimes with
vomiting, and diarrhea are common. The muscles are weak and often go into
spasm. There are often emotional changes, particularly irritability and
depression. Because of salt loss, a craving for salty foods is common.
Finally, the increase in ACTH due to the loss of cortisol will usually
produce a darkening of the skin that may look like an inappropriate tan on a
person who feels very sick.
Unfortunately, the slowly progressive chronic
symptoms are usually missed or ignored until a sudden event like a flu
virus, an accident, or the need for surgery suddenly precipitates a dramatic
change for the worse because of the deficient response from the adrenals to
one of these stresses. This is referred to as an Addisonian crisis and is a
medical emergency.
How is Addison's Disease diagnosed?
A medical history of the symptoms mentioned above, especially hyperpigmentation of the skin or
gums, is often enough to raise a strong suspicion, prompting the appropriate
tests. Quite often, however, the first clue is from the abnormal results of
routine tests done in a hospital or doctor's office. These may include an
elevated blood level of potassium, a low blood level of sodium, a shift in
the ratio of certain white blood cells, or surprising changes on an EKG or
chest x-ray that are caused by high potassium or low blood volume. Other
causes for these changes, particularly from medications, must be considered
first.
A definitive diagnosis of Addison's disease requires that definitive
tests be carried out. These tests measure the amount of cortisol and
aldosterone in the blood and urine, and document a lack of the normal
increase in the levels of these two hormones after administration of ACTH
given by injection. An elevated blood level of ACTH should also be found.
If
the patient is very sick and Addison's disease is suspected, treatment can
be initiated while the diagnostic tests are being done. Once the diagnosis
of Addison's disease is established, an effort should be made to find the
cause by checking for tuberculosis and other infections through skin tests
and x-rays. Antibodies to adrenal tissue, especially to 21OH can now be
measured, and are specific to autoimmune Addison’s disease.
How
is Addison's Disease Treated?
Since all of the manifestations of Addison's disease are
caused by the lack of cortisol and aldosterone, the treatment is to replace
these with similar steroids. Cortisol is usually replaced orally by
hydrocortisone or cortisone acetate, less often with prednisone tablets,
divided into morning and afternoon doses. Aldosterone is replaced by an
aldosterone-like synthetic steroid, fludrocortisone (Florinef) tablets given
once daily. The doses of each of these medications are adjusted for the
individual's size and any co-existing medical conditions.
In emergencies or
during surgery, hydrocortisone must be given intravenously.
Patients with
Addison's disease should be taught to treat minor illnesses with extra salt,
fluids and extra hydrocortisone. This is especially important if fever,
vomiting or diarrhea is present. Persistence of these signs requires
immediate treatment in an emergency room with intravenous saline (salt
water) and hydrocortisone.
Since Addison's disease is a chronic condition,
daily replacement medication can never be stopped. Proper maintenance
treatment requires regular visits to a physician for examinations,
laboratory tests, and discussions about symptoms. Certain blood tests,
including sodium, potassium, blood counts and plasma renin are very useful
in monitoring the response to adjustments in dosage. There is no single
blood or urine test that is perfect by itself.
Why should Addisonians consult an
Endocrinologist?
Endocrinologists are specialists in hormonal
diseases, including Addison's disease. Because of the rarity of the disease,
an endocrinologist will have more training and experience in properly
diagnosing and treating Addison's disease than most physicians.
Are there related diseases?
Secondary adrenal insufficiency, caused by a lack of ACTH,
results in a deficiency of cortisol, but usually not aldosterone. The cause
is either pituitary disease, such as a tumor, or the prolonged use of
"steroid" medication that suppresses ACTH. The treatment is simply to
replace cortisol, usually with the synthetic steroid prednisone, but
sometimes hydrocortisone or cortisone acetate.
Auto-immune Addison's
disease, the most common type, can be associated with other autoimmune
diseases that similarly affect other endocrine glands. The most common one
is the thyroid. If an underactive thyroid (hypothyroidism) coexists with
Addison's disease, this is called Schmidt's syndrome. Less commonly
associated auto-immune diseases are insulin dependent diabetes mellitus, and
insufficiencies of the parathyroid glands, gonads, and vitamin B12
absorption (pernicious anemia).
Why is Addison's considered a rare disorder?
There are no accurate statistics on the incidence of Addison's disease in the
United States. A study in London showed thirty-nine cases per million
population as of 1960. Twelve were due to tuberculosis. In the
non-tuberculosis group, women were three times more likely to have Addison's
disease. Extrapolation of these figures to the U.S. would give about 8,800
cases, but this is probably an underestimation.
How normal is an Addisonian's life?
As long as the proper dose of replacement medication is taken every day,
an Addisonian can have a normal crisis-free life. There are no specific
physical or occupational restrictions.
Routine care includes regular
physician visits, avoidance of dehydration, and the use of extra medication
during illness. Pregnancy is possible, but will require extra monitoring of
the replacement medication.
Every Addisonian should wear an identification
bracelet or preferably a necklace stating that he or she has the disease, to
insure proper emergency treatment. An identification card outlining
treatment is also suggested.
Written by Dr. Paul Margulies, MD, FACP, FACE
Medical Director, NADF
Clinical Associate Professor of Medicine, New York University Medical
School
This page is dedicated in memory of Jeremy Young by his parents, Mr. & Mrs.
Young
|