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Hypothyroidism Introduction |
Hypothyroidism
is the clinical representation of
having decreased levels of
circulating thyroid hormones in a
particular individual. There are two
main thyroid hormones secreted by
the thyroid gland, T4 and T3.
Outside of the gland, T4 is broken
down into T3 by specific enzymes.
T4 does not affect the tissues in
the body, as T3 is the active form
of thyroid hormone.
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Primary
hypothyroidism can result
due to a decrease in production
from the thyroid, a decrease in
conversion or breakdown of T4 to
T3 in the body, or a decrease in
the signal from the brain to tell
the thyroid gland to make more
hormone. [1] Secondary hypothyroidism results
from removal of the thyroid gland,
radiation of the gland, and from
drug therapy.
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Sub-clinical
hypothyroidism is now
seen as a condition that reflects
low levels of thyroid hormones,
with clinical symptoms, but is not
diagnostic of hypothyroidism. [2]
This form of hypothyroidism has
garnered much interest within the
medical community.
Hashimoto's
thyroiditis is an autoimmune disease
that causes hypothyroidism as well. It
is the result of anti-bodies
attacking the signaling molecules
responsible for hormone synthesis.
Hashimoto's is the most common cause
of hypothyroidism in the US. In the
past, the most common cause was
iodine deficiency, but that problem
was solved by adding iodine to table
salt (iodized salt). [3]
The potential risks
and development rates of
hypothyroidism increase with age. It affects women ten times as often
as men. In fact, Hashimoto's affects
women 8 times as often as men.
It is
estimated that between 1-4% of the
US population has hypothyroidism.
That number can possibly increase to
10-25%, if sub-clinical or mild
hypothyroidism is included into the
statistical equation. [4]
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Hypothyroidism Signs and Symptoms
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Symptoms of
hypothyroidism include:
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Constipation
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Dry skin
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Coarse dry hair
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Fatigue
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Mental fogginess
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Depression
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Cold intolerance
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Weight gain
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Joint pain
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Muscle cramps.
Clinical signs of
hypothyroidism include, but are not
limited to; goiter,
decreased deep tendon reflexes,
hoarse voice, brittle nails, dry
skin, muscle weakness, low basal
body temperature, and menstrual
irregularities. [5]
Hypothyroidism
causes a decrease in metabolism
and an overall slowing of the
systems of the body. Most body
systems can be affected, including
the cardiovascular, digestive, and
neurological systems. Children with
hypothyroidism can have mental
deficits that result in mental
retardation, and growth deficits that
can be so severe that cretinism
develops. [6]
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Learn More About
Hypothyroidism |
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