T R E AT I N G

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Hypothyroidism
THYROI
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IT DESERVES THE BEST CARE HY R O I D AW OM
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What is hypothyroidism? RADIOACTIVE IODINE TREATMENT

Hypothyroidism frequently develops as a desired therapeutic
Hypothyroidism (underactivity of the thyroid gland) occurs goal after the use of radioactive iodine treatment for
when the thyroid gland produces less than the normal amount hyperthyroidism.
of thyroid hormone. The result is the slowing down of
many bodily functions. Although hypothyroidism may be THYROID OPERATION
temporary, it usually is a permanent condition. Of the nearly Hypothyroidism may be related to surgery on the thyroid
27 million people suffering from a thyroid condition, most gland, especially if most of the thyroid has been removed.
have hypothyroidism.
MEDICATIONS
What are the features of hypothyroidism? Lithium, high doses of iodine, and amiodarone (Cordarone,
Pacerone) can cause hypothyroidism.
In its earliest stage, hypothyroidism may cause few symptoms,
since the body has the ability to partially compensate for a SUBACUTE THYROIDITIS
failing thyroid gland by increasing the stimulation to it, much This condition may follow a viral infection and is characterized
like pressing down on the accelerator when climbing a hill by painful thyroid gland enlargement and inflammation,
to keep the car going the same speed. As thyroid hormone which results in the release of large amounts of thyroid
production decreases and the bodys metabolism slows, a hormones into the blood. Fortunately, this condition usually
variety of features may result. resolves spontaneously. The thyroid usually heals itself over
several months, but often not before a temporary period of
hypothyroidism occurs.
Pervasive fatigue
Drowsiness POSTPARTUM THYROIDITIS
Forgetfulness Five percent to 10 percent of women develop mild to
moderate hyperthyroidism within several months of giving
Difficulty with learning birth. Hyperthyroidism in this condition usually lasts for
Dry, brittle hair and nails approximately 1 to 2 months. It is often followed by several
Dry, itchy skin months of hypothyroidism, but most women will eventually
recover normal thyroid function. In some cases, however,
Puffy face the thyroid gland does not heal, so the hypothyroidism
Constipation becomes permanent and requires lifelong thyroid hormone
Sore muscles replacement.

Weight gain and fluid retention SILENT THYROIDITIS

Heavy and/or irregular menstrual flow Transient (temporary) hyperthyroidism can be caused by
Increased frequency of miscarriages silent thyroiditis, a condition which appears to be the same as
postpartum thyroiditis but not related to pregnancy. It is not
Increased sensitivity to many medications accompanied by a painful thyroid gland.

What are the major causes of hypothyroidism? CONGENITAL CONDITION

An infant may be born with an inadequate amount of thyroid
AUTOIMMUNE THYROIDITIS tissue or an enzyme defect that does not allow normal thyroid
(Hashimotos thyroiditisseparate brochure available) hormone production. If this condition is not treated promptly,
physical stunting and/or mental damage (cretinism) may
The bodys immune system may produce a reaction in the develop.
thyroid gland that results in hypothyroidism and, most often,
a goiter (enlargement of the thyroid). Other autoimmune PITUITARY HYPOTHYROIDISM
diseases may be associated with this disorder, and additional Any destructive disease of the pituitary gland may cause
family members may also be affected. damage to the cells that secrete Thyroid Stimulating Hormone
 (TSH), which stimulates the thyroid to produce normal Since most cases of hypothyroidism are permanent and often
amounts of thyroid hormone. This is a very rare cause of progressive, it is usually necessary to treat this condition
hypothyroidism. throughout ones lifetime. Periodic monitoring of TSH levels
and clinical status are necessary to ensure that the proper
dose is being given, since medication doses may have to be
How is hypothyroidism diagnosed? adjusted from time to time. Optimal adjustment of thyroid
hormone dosage is critical, since the body is very sensitive
to even small changes in thyroid hormone levels. The tablets
Characteristic symptoms and physical signs, which can be come in 12 different strengths, and it is essential to take them
detected by a physician, can signal hypothyroidism. However, in a consistent manner every day. A dose of thyroid hormone
the condition may develop so slowly that many patients do that is too low may fail to prevent enlargement of the thyroid
not realize that their body has changed, so it is critically gland, allow symptoms of hypothyroidism to persist, and be
important to perform diagnostic laboratory tests to confirm associated with increased serum cholesterol levels, which may
the diagnosis and to determine the cause of hypothyroidism. increase the risk for atherosclerosis and heart disease. A dose
that is too high can cause symptoms of hyperthyroidism, create
TSH (THYROID-STIMULATING HORMONE OR excessive strain on the heart, and lead to an increased risk of
THYROTROPIN) TEST developing osteoporosis.
An increased TSH level in the blood is the most accurate
indicator of primary (nonpituitary) hypothyroidism. Pro- It is extremely important that women planning to become
duction of this pituitary hormone is increased when the pregnant are kept well adjusted, since hypothyroidism can
thyroid gland even slightly underproduces thyroid hormone. affect the development of the baby. During pregnancy, thyroid
hormone replacement requirements often change, so more
OTHER TESTS frequent monitoring is necessary. Various medications and
Estimates of free thyroxine - the active thyroid hormone in supplements (particularly iron) may affect the absorption of
the blood. It is important to note that there is a range of free thyroid hormone; therefore, the levels may need more frequent
thyroxine levels in the blood of normal people, similar to monitoring during illness or change in medication.
the range for height, and that a value of free thyroxine that is
within normal limits for the general population may not be Thyroid hormone is critical for normal brain development
appropriate for a particular individual. in babies. Infants requiring thyroid hormone therapy should
NOT be treated with purchased liquid suspensions, since
Thyroid autoantibodies - indicates the likelihood of auto the active hormone may deteriorate once dissolved and the
immune thyroiditis being the cause of hypothyroidism. baby could receive less thyroid hormone than necessary.
Instead, infants with hypothyroidism should receive their
A primary care physician may make the diagnosis of thyroid hormone by crushing a single tablet daily of the
hypothyroidism, but assistance is often needed from an correct dose and suspending it in one teaspoon of liquid and
endocrinologist, a physician who is a specialist in thyroid administering it properly.
diseases.
Appropriate management of hypothyroidism requires con-
tinued care by a physician experienced in the treatment of this
How is hypothyroidism treated? condition.

For more information please visit

Hypothyroidism is treated with a single daily dose of www.thyroidawareness.com
levothyroxine, given as a tablet. An experienced physician
can prescribe the correct form and dosage to return the thyroid
balance to normal. Older patients who may have underlying
heart disease are usually started at a low dose and gradually
increased while younger healthy patients can be started on
full replacement doses at once. Thyroid hormone acts very
slowly in some parts of the body, so it may take several
months after treatment is started to notice improvement in
symptoms.

Prepared by the American Association of Clinical Endocrinologists (AACE), a not-for-profit national organization of highly qualified specialists in hormonal and
metabolic disorders whose primary professional activities focus on providing high-quality specialty care to patients with endocrine problems such as thyroid disease.
Supported by an unrestricted educational grant from Abbott Laboratories.

2008 AACE - Permission is granted for reproduction of this publication.