| What
are the symptoms of hyperthyroidism?
Thyroid hormone generally controls the pace of all of the processes
in the body. This pace is called your metabolism. If there
is too much thyroid hormone, every function of the body tends to
speed up. It is not surprising then that some of the symptoms of
hyperthyroidism are nervousness, irritability, increased perspiration,
heart racing, hand tremors, anxiety, difficulty sleeping, thinning
of your skin, fine brittle hair, and muscular weakness—especially
in the upper arms and thighs. You may have more frequent bowel movements,
but diarrhea is uncommon. You may lose weight despite a good appetite
and, for women, menstrual flow may lighten and menstrual periods
may occur less often.
Hyperthyroidism usually begins slowly. At first, the symptoms may
be mistaken for simple nervousness due to stress. If you have been
trying to lose weight by dieting, you may be pleased with your success
until the hyperthyroidism, which has quickened the weight loss,
causes other problems.
In Graves’ disease, which is the most common form of hyperthyroidism,
the eyes may look enlarged because the upper lids are elevated.
Sometimes, one or both eyes may bulge. Some patients have swelling
of the front of the neck from an enlarged thyroid gland (a goiter).
|
|
How is hyperthyroidism treated?
No single treatment is best for all patients with hyperthyroidism.
Your doctor’s choice of treatment will be influenced by your
age, the type of hyperthyroidism that you have, the severity of
your hyperthyroidism, and other medical conditions that may be affecting
your health. It may be a good idea to consult with a physician who
is experienced in the treatment of hyperthyroid patients. If you
are unconvinced or unclear about any thyroid treatment plan, a second
opinion is a good idea.
Antithyroid drugs
Drugs known as antithyroid agents—methimazole
(Tapazole®) or propylthiouracil (PTU)—may be prescribed
if your doctor chooses to treat the hyperthyroidism by blocking
the thyroid gland’s ability to make new thyroid hormone. These
drugs work well to control the overactive thyroid, bring prompt
control of hyperthyroidism, and do not cause permanent damage to
the thyroid gland. In about 20% to 30% of patients with Graves’
disease, treatment with antithyroid drugs for a period of 12 to
18 months will result in prolonged remission of the disease. For
patients with toxic nodular or multinodular goiter, antithyroid
drugs are used in preparation for either radioiodine treatment or
surgery. Antithyroid drugs cause allergic reactions in about 5%
of patients who take them. Common minor reactions are red skin rashes,
hives, and occasionally fever and joint pains. A rarer (occurring
in 1 of 500 patients), but more serious side effect is a decrease
in the number of white blood cells. Such a decrease can lower your
resistance to infection. Very rarely, these white blood cells disappear
completely, producing a condition known as agranulocytosis,
a potentially fatal problem if a serious infection occurs. If you
are taking one of these drugs and get an infection such as a fever
or sore throat, you should stop the drug immediately and have a
white blood cell count that day. Even if the drug has lowered your
white blood cell count, the count will return to normal if the drug
is stopped immediately. But if you continue to take one of these
drugs in spite of a low white blood cell count, there is a risk
of a more serious, even life-threatening infection. Liver damage
is another very rare side effect. You should stop the drug and call
your doctor if you develop yellow eyes, dark urine, severe fatigue,
or abdominal pain.
Radioactive iodine
Another way to treat hyperthyroidism is to damage or destroy the
thyroid cells that make thyroid hormone. Because these cells need
iodine to make thyroid hormone, they will take up any form of iodine
in your blood stream, whether it is radioactive or not. The radioactive
iodine used in this treatment is administered by mouth, usually
in a small capsule that is taken just once. Once swallowed, the
radioiodine gets into your blood stream and quickly is taken up
by the overactive thyroid cells. The radioiodine that is not taken
up by the thyroid cells disappears from the body within days. It
is either eliminated in the urine or transformed by radioactive
decay into a nonradioactive state. Over a period of several weeks
to several months (during which time drug treatment may be used
to control hyperthyroid symptoms), radioactive iodine damages the
cells that have taken it up. The result is that the thyroid or thyroid
nodules shrink in size, and the level of thyroid hormone in the
blood returns to normal. Sometimes patients will remain hyperthyroid,
but usually to a lesser degree than before. For them, a second radioiodine
treatment can be given if needed. More often, hypothyroidism
(an underactive thyroid) occurs after a few months. In fact, most
patients treated with radioactive iodine will become hypothyroid
after a period of several months to many years. Hypothyroidism can
easily be treated with a thyroid hormone supplement taken once a
day (see the Hypothyroidism
brochure).
Radioactive iodine has been used to treat patients for hyperthyroidism
for over 60 years. Because of concern that the radioactive iodine
might somehow damage other cells in the body, produce cancer, or
have other long-term unwanted effects such as infertility or birth
defects, the physicians who first used radioiodine treatments were
careful to treat only adults and to observe them carefully for the
rest of their lives. Fortunately, no complications from radioiodine
treatment have become apparent over many decades of careful follow-up
of patients. As a result, in the United States more than 70% of
adults who develop hyperthyroidism are treated with radioactive
iodine. More and more children are also being treated with radioiodine.
Surgery
Your hyperthyroidism can be permanently cured by surgical removal
of most of your thyroid gland. This procedure is best performed
by a surgeon who has much experience in thyroid surgery. An operation
could be risky unless your hyperthyroidism is first controlled by
an antithyroid drug (see above) or a beta-blocking drug (see below).
Usually for some days before surgery, your surgeon may want you
to take drops of nonradioactive iodine—either Lugol’s
iodine or supersaturated potassium iodide (SSKI). This extra iodine
reduces the blood supply to the thyroid gland and thus makes the
surgery easier and safer. Although any surgery is risky, major complications
of thyroid surgery occur in less than 1% of patients operated on
by an experienced thyroid surgeon. These complications include damage
to the parathyroid glands that surround the thyroid and control
your body’s calcium levels (causing problems with low calcium
levels) and damage to the nerves that control your vocal cords (causing
you to have a hoarse voice).
After your thyroid gland is removed, the source of your hyperthyroidism
is gone and you will likely become hypothyroid. As with hypothyroidism
that develops after radioiodine treatment, your thyroid hormone
levels can be restored to normal by treatment once a day with a
thyroid hormone supplement.
Beta-blockers
No matter which of these three methods of treatment you have
for your hyperthyroidism, your physician may prescribe a class of
drugs known as the beta adrenergic blocking agents that
block the action of thyroid hormone on your body. They usually make
you feel better within hours, even though they do not change the
high levels of thyroid hormone in your blood. These drugs may be
extremely helpful in slowing down your heart rate and reducing the
symptoms of palpitations, shakes, and nervousness until one of the
other forms of treatment has a chance to take effect. Propranolol
(Inderal®) was the first of these drugs to be developed. Some
physicians now prefer related, but longer-acting betablocking drugs
such as atenolol (Tenormin®), metoprolol (Lopressor®) and
nadolol (Corgard®), and Inderal-LA® because of their more
convenient once- or twice-a-day dosage.
Other family members at risk
Because hyperthyroidism, especially Graves’ disease, may run
in families, examinations of the members of your family may reveal
other individuals with thyroid problems.
|
Print page
Email page
