Goiter and Iodine Deficiency
One fifth of the world's population (1 billion people) have diets
that are deficient in iodine. People in these areas commonly have
thyroid enlargement (goiter), and often thyroid nodules as well.
In European countries and many other developed countries iodine
intake has only risen to normal levels in recent years. Here in
America, many in the population have thyroid enlargement and nodules
as a result of iodine deficiency in the past.
In the United States, dietary iodine deficiency was eliminated
early in the last century with the addition of iodine to salt and
its presence in milk and bread products. And even though dietary
iodine is dropping in some parts of the country to borderline and
even slightly low levels, goiters here are not due to a lack of
iodine.
Therefore if you have an enlargement of your thyroid gland and
have not moved to the United States from a country with iodine deficiency,
you need to look for another cause for your problem.
The most common cause of goiter here would be a change in thyroid
function. If your thyroid begins to fail and hormone levels fall
below normal, your pituitary gland senses that there is not enough
thyroid hormone in the blood and increases thyroid function and
sometimes thyroid size through the action of thyroid stimulating
hormone, which it releases into the bloodstream. If your thyroid
gland becomes overactive, antibodies stimulate the gland to overproduce
thyroid hormone and often enlarge the gland as well.
Subacute thyroiditis can also result in a larger and sometimes
tender thyroid.
If none of these are your problem, your doctor will examine you
to be sure that your thyroid is not enlarged due to the presence
of a nodule, which are usually benign but occasionally malignant.
The treatment of a goiter will depend on the cause. Usually if
it's due to the thyroid becoming overactive or underactive, correction
of the underlying condition will prevent further growth and often
result in a return to normal or near normal size. If the gland is
so large as to be cosmetically disfiguring, it may be removed surgically.
This is often done if a thyroid has been markedly enlarged for years,
in which case an enlarged thyroid may not shrink very much no matter
what the treatment. If that is your situation, our best advice is
to choose your surgeon well, for an experienced thyroid surgeon
lowers your risk for complications, particularly damage to the vocal
cord nerves or parathyroid glands. Choosing a thyroid surgeon is
important and discussed in more detail elsewhere on this website
under Find a Doctor. Occasionally a thyroid gland will enlarge due
to the presence of a lymphoma or other tumor within the gland. Treatment
will depend on the nature of the tumor and for this you'll often
need to see an oncologist as well as a thyroid specialist, and usually
a thyroid surgeon.
Sometimes a benign nodule or goiter may decrease in size with thyroid
hormone or radioactive iodine treatment. These situations are very
individual, and it's best to see a thyroid specialist who is up
to date with current research and is in the best position to know
what's best for you.
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