
Thyroid Disease
Hypothyroidism (low thyroid hormone)
Hyperthyroidism (high thyroid hormone)

Two major types of thyroid disease...

If your doctor says you are "hypothyroid," it means you have a
fairly common chronic medical condition: Your thyroid produces too
little thyroid hormone. Fortunately, hypothyroidism can be treated
easily, effectively, inexpensively and painlessly.

On the other hand, if your doctor tells you that you are
"hyperthyroid," your have the opposite problem: Your thyroid gland
produces too much thyroid hormone. The most common type of
hyperthyroidism, Graves' disease, is the disorder that afflicts
First Lady Barbara Bush.

Both hypothyroidism and hyperthyroidism are caused by improper
functioning of the thyroid, a gland located in the front of the
neck, just below the Adam's apple. The thyroid gland produces
hormones that affect most organs, including the heart, brain,
liver, kidneys and skin.


Wide variety of symptoms....

Because thyroid hormone affects virtually every cell in your body,
you may suffer from a wide spectrum of complaints if you have
thyroid disease.
 
If your thyroid produces too little thyroid hormone, your heartbeat
may be slowed and you may feel tired, depressed and run down. Your
skin, hair and fingernails may grow more slowly, so that they
become rough, dry and brittle. You may be overly sensitive to cold
temperatures. Other signs and symptoms of hypothyroidism include
constipation, anemia, fatigue, loss of appetite, slight increases
weight, irregular or absent menstrual periods, swollen ankles,
puffiness about the face, elevated cholesterol and, possibly,
hypertension.

If, however, your thyroid produces too much hormone, you may
experience a fast, pounding heartbeat -- even at rest, and you may
lose weight even if your diet and appetite have not changed. Other
symptoms of hyperthyroidism include frequent bowel movements,
inability to sleep, nervousness, muscle weakness and fine tremors
of the fingers and tongue.


Many causes...

Thyroid disease has many different causes. In the United States,
the most common cause of hypothyroidism is Hashimoto's disease, a
condition in which the body inexplicably begins treating the
thyroid as if it were a "foreign" tissue -- and injures it. As the
damaged thyroid gland produces less and less hormone, the pituitary
gland secretes another hormone, thyroid stimulating hormone (TSH),
to try to encourage the thyroid to work harder. This increased
demand on the thyroid may cause it to enlarge -- creating what is
commonly known as a "goiter."

Hypothyroidism may also develop in people who have had surgical or
radioactive iodine treatment for an overactive thyroid, or who have
received high doses of radiation for cancers of the head and neck.
Radiation treatments to the head or neck, quite commonly
administered to children between 1920 and 1960 for enlarged thymus,
acne or other non-thyroid related problems, may also increase the
risk of hypothyroidism.

Sometimes, infants are born without a thyroid gland or with a gland
that does not function normally. These children must be treated for
their hypothyroidism immediately -- and for life -- if they are to
develop normally.


Affects millions, especially women....

Thyroid disease, particularly hypothyroidism, is a fairly common
medical condition. It is difficult to estimate how many people are
hypothyroid, since many individuals are hypothyroid without knowing
it. Researchers estimate that at least 6 to 7 million Americans are
hypothyroid -- but only on-half have been diagnosed. Most of the
remainder feel varying degrees of discomfort or lethargy and often
incorrectly attribute such symptoms to normal aging. Another 1
million Americans are hyperthyroid.

Hypothyroidism primarily affects women -- it is about four times
more common in women than in men -- but can occur in either sex and
at any age. It affects older people more often than younger people
and is most common in women over the age of 50. In the United
States, it is estimated that less than 1% of young people are
hypothyroid, whereas up to 10% of the elderly are affected.
Hyperthyroidism, too, is more common in women, most often affecting
those in their 30s and 40s.


Confirmed by simple blood test...

In the past, hypothyroidism could not be detected until it was
fairly advanced. Today, however, sophisticated ne laboratory tests
enable hypothyroidism to be detected earlier. One such test, the
sensitive TSH assay, measures how much TSH is circulating in the
blood. If the TSH assay shows that you have a high level of TSH,
this means that your pituitary gland is sensing that your thyroid
is not making enough thyroid hormone to meet its needs. Thus, you
are hypothyroid.


Treatment critical to good health...

It is important to treat both hypothyroidism and hyperthyroidism,
because if left untreated, these diseases can have serious
consequences. The risks of not treating hypothyroidism differ
depending on the affected individual. In newborns who cannot make
enough thyroid hormone prompt treatment is crucial in preventing
mental retardation, delayed growth, facial deformities and other
severe abnormalities. That is why all newborns undergo thyroid
screening ar birth.

Children and adolescents who become hypothyroid also risk abnormal
mental and physical development it they are not treated promptly.

In adults, the consequences of untreated hypothyroidism are usually
less severe but may still cause considerable discomfort or
disability. If severe hypothyroidism goes untreated in an adult,
mental illness or heart disease may result. Of even greater
importance, severe, untreated hypothyroidism can result in death.

Left untreated, hyperthyroidism can also have serious effects. For
example, certain tissues, particularly those behind the eyeball,
can thicken. If the condition remains untreated, this abnormal
tissue behind the eye can push the eyeball forward in the socket,
producing a wide-eyed appearance that can threaten vision. In
advanced cases of untreated hyperthyroidism, a life-threatening
metabolic condition known as "thyroid storm" can occur.


Thyroid disease: Treatable, not curable...

Since most cases of hypothyroidism result from either permanent
destruction or abnormality of the thyroid gland, the condition
cannot be cured. However, it can be treated easily and
inexpensively with a synthetic thyroid hormone called
levothyroxine. Levothyroxine, which works in the body exactly the
way natural thyroid hormone does, must be taken daily for life by
the vast majority of hypothyroid patients.

Precise dosage. The amount of thyroid hormone replacement that
patients require varies, and many tablet strengths are available.
Since your physician uses sensitive blood tests to determine the
dosage that is best for you, it is important to follow your
physician's instructions and take the proper dosage of
levothyroxine every day.

Slow, gradual improvement in hypothyroidism. The symptoms of
hypothyroidism do not disappear as soon as you begin taking thyroid
hormone. However, if you remain patient and continue to take the
medication as directed, you will notice a slow and gradual
improvement in your appearance and well being. Even if you are
severely hypothyroid, a few months of treatment should relieve all
of your hypothyroid-related symptoms. But feeling better does not
mean that you can stop taking thyroid hormone! Even though your
symptoms have subsided, it is important to continue to take your
medicine. The tablets you take replace a hormone your thyroid no
longer makes in sufficient quantities. If you stop taking the
medication, your body will take about a month to use up the
majority of hormone you have already taken. Then, over the
following weeks, your old symptoms will gradually return.

Hyperthyroidism treatment more difficult. The treatment for
hyperthyroidism is not quite as easy, inexpensive or painless as
that for hypothyroidism. If your are hyperthyroid, your doctor may
attempt to shrink your thyroid with radioactive iodine. In this
procedure, radioactive iodine is used to destroy the cells that
produce thyroid hormone, thus lessening the amount of thyroid
hormone produced. Although this procedure is effective in treating
hyperthyroidism, its usual end result is to render you hypothyroid.
That means you -- like people who are hypothyroid because of
Hashimoto's disease or surgery for thyroid cancer -- must take
synthetic thyroid hormone to replace the hormone your thyroid no
longer makes in sufficient quantities. Antithyroid (thyroid
blocking) drugs are less frequently used to stop your thyroid from
producing excess hormone. If drug therapy fails, radioactive iodine
is used.


Remember to see your doctor for checkups...

Once you have been prescribed thyroid hormone replacement therapy,
it is important to continue seeing your doctor for checkups. Your
physician may obtain thyroid function tests annually and, depending
on the results, adjust your dose of thyroid hormone. Moreover,
during pregnancy, and as you grow older, your thyroid hormone
requirements change, which may necessitate a dosage adjustment.
In the past, physicians used to prescribe higher doses of thyroid
hormone. Now accurate tests are available to determine precisely
how much hormone a person needs, physicians can prescribe smaller,
equally effective doses. If you have been taking levothyroxine or
any other thyroid medicine for many years and have not been checked
recently, you may want to ask your physician whether it is time to
review your dosage needs.


A word about thyroid hormone preparations...

All thyroid hormone preparations are not the same. If your
physician prescribes a certain brand of levothyroxine and your
pharmacist asks if you would like to switch from that brand, please
check with your physician first. Even though the labels say that
the two preparations have the same strength, they may not deliver
exactly the same amount of thyroid hormone. A leading consumer
magazine and most U.S. endocrinologists agree: Thyroid medications
should only be switched in conjunction with complete retesting.

Desiccated thyroid. Many older people with hypothyroidism have been
taking a different kind of thyroid medication call desiccated
thyroid, which was prescribed in the years before synthetic
levothyroxine became available. Desiccated thyroid tablets are made
from animal thyroid glands and contain a form of thyroid hormone
that can cause a rapid heartbeat and other undesirable effects on
the heart. Most experts today consider desiccated thyroid an
outmoded medication. If you were diagnosed as having hypothyroidism
20 to 30 years ago...and if you've been on the same medication ever
since...you should check with your doctor. Anyone taking desiccated
thyroid--often called "thyroid extract" or "thyroid pills"--should
contact a physician to determine whether he or she should be taking
levothyroxine instead.


If you would like more information about thyroid disease, you may
want to contact:

Thyroid Foundation of America, Inc.
630 Ambulatory Care Center
Massachusetts General Hospital
Boston, Massachusetts  02114

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