Treatments
Surgery is rarely necessary
in the treatment of hyperthyroidism. Graves’ disease may
be treated with radioactive iodine or antithyroid drugs,
namely propylthiouracil
(PTU) and
methimazole (tapazole).
Radioactive
iodine treatment
One dose of radioactive
iodine, taken by mouth, is usually sufficient to cure
Graves’ disease.
It works by destroying the ability of
thyroid cells to make thyroid hormone. The iodine is
predominantly excreted in the urine.
I advise my patients
to urinate promptly after their treatment to minimize the
possibility of side-effects from the medication. Those who
undergo radioactive iodine treatment should not have
prolonged contact with children for appro ximately three
days – because children are more sensitive to radiation.
I
also advise patients who have recently undergone treatment
to flush the toilet twice, rinse the sink twice after
brushing their teeth and to use plastic silverware and
paper plates. Alternatively, dishes and utensils may be
cleaned in a dishwasher.
As daunting as it may sound, the
treatment of Graves’ disease with radioactive iodine has
not been shown to increase the risk of cancer.
However, many people who receive radioactive iodine do
subsequently become hypothyroid (described below) since
the treatment destroys the ability of the thyroid cells to
produce thyroid hormone.
Hypothyroidism may occur months
or even years after therapy. For people who have undergone
this treatment, it’s best to have thyroid function tests
performed yearly at least.
Radioactive iodine is not appropriate for pregnant women
or those women who plan to conceive in the near future. I
instruct all my patients of reproductive age not to become
pregnant within nine months of treatment.
Radioactive iodine is also appropriate treatment for
nodules in the elderly that produce excessive amounts of
thyroid hormone.
Antithyroid
drugs
Unlike radioactive iodine
treatment, which actually destroys thyroid tissue and thus
the ability to make hormone, antithyroid drugs are used to
inhibit thyroid hormone production. For this reason, they
have only a 30 to 50% chance of actually curing Graves’
disease.
They are generally taken for 12-24 months.
Hyperthyroidism can be well controlled by these
medications, but once the drugs are stopped, the disease
may relapse. Propylthiouracil (PTU) is taken two to four
times per day and tapazole one or two times per day.
PTU
additionally inhibits the conversion of T4 to T3.
A
major adverse effect of antithyroid drugs is
agranulocytosis, which is
a severe decrease in the white blood cells necessary to
fight infections. T
his condition can be life threatening
for a person who gets sick with a dangerously low
granulocyte (white blood
cell) count. I instruct my patients to immediately stop
their antithyroid medication if they get a fever, sore
throat or any other sign of infection and have a complete
blood count checked.
If the white blood cell count is
normal, they may resume their antithyroid drugs.
Agranulocytosis is usually reversible if the antithyroid
medication is stopped. Other side effects of these drugs
include rashes, hepatitis (liver inflammation), and joint
aches.
After
treatment
I inform all hyperthyroid
patients that they must be careful about the amount of
food they eat following treatment if they do not want to
gain weight.
With the restoration of normal thyroid
function, an increase in weight will accompany a
persistently exaggerated appetite.
Hypothyroidism in Pregnancy
Several symptoms are
common to both pregnancy and hyperthyroidism. These
symptoms include: palpitations, anxiety, shortness of
breath and fatigue. Ideally, hyperthyroidism should be
definitively treated prior to becoming pregnant.
If this
is not possible, antithyroid drugs are the best
treatment option during pregnancy. Both PTU and
methimazole are transferred from the mother to the fetus
through the umbilical cord, but PTU is the preferable
drug since it is less transferred.
It has been suggested
that an abnormality of the fetal scalp may be associated
with methimazole. I use the lowest possible dose of PTU
in my pregnant patients and try to stop treatment in the
third trimester if possible.
Women who are pregnant and
hyperthyroid should be carefully monitored throughout
their pregnancy. As well, because the drug is in the
mothers’ system, women who take antithyroid medication
should bottle-feed instead of nurse.
Hypothyroidism
Where hyperthyroid
people make too much thyroid hormone, hypothyroid people
don’t make enough. Again, women develop hypothyroidism
more frequently than men, and it is most often diagnosed
in people between the ages of thirty and sixty.
A common
form of hypothyroidism results from the treatment of
Graves’ disease with radioactive iodine.
Hashimoto’s thyroiditis
is the most common non-drug induced form of
hypothyroidism.
In this condition, antibodies (normally
used to fight infections) are produced against the TSH
receptor which inhibits production of thyroid hormone.
Clinical features
The following is a list of
signs and symptoms commonly associated with
hypothyroidism:
- Fatigue
- Weight gain
- Constipation
- Decreased pulse rate
- Cold intolerance
- Diminished reflexes
- Goiter
- Dry skin
- Dry hair
- Hair loss
- Brittle nails
- Depression
- Decreased libido
- Menstrual
irregularities
- Decreased fertility
- Muscle aches
- Swelling of the
eyelids, hands and feet
- Increased cholesterol
Diagnosis
The diagnosis of
hypothyroidism is confirmed by blood tests that show an
increase in TSH and decreased levels of T4 and T3.
Treatments
There is no cure for
hypothyroidism. Synthetic T4
(levothyroxine), an oral medication taken
daily, is the treatment of choice. When used
appropriately, this is a very safe medication.
Hypothyroidisim in Pregnancy
Levothyroxine may be
taken during pregnancy and breast-feeding. During
pregnancy, the thyroid gland enlarges and thyroid
hormone requirements may increase. I carefully monitor
all hypothyroid pregnant women and increase their
thyroid hormone doses as necessary.
All babies born in
American hospitals are routinely screened for
hypothyroidism.
Thyroiditis
Post-partum thyroiditis
Post-partum thyroiditis is
an inflammation of the thyroid gland that occurs
following delivery, and it is estimated that this
condition occurs in up to 20% of mothers.
It often goes
undiagnosed, as it is a painless condition and it’s
symptoms, such as nervousness, fatigue, weight loss and
emotional changes are often attributed to the natural
post-partum state.
If you suspect you are experiencing a
post-partum depression, you should have your thyroid
hormone blood levels checked. In post-partum thyroiditis,
there is an initial hyperthyroid phase that may last two
to three months, which is then followed by a hypothyroid
phase of up to nine months. I
often treat women with T4
during the hypothyroid phase. In approximately 10% of
women with post-partum thyroiditis, the hypothyroidism
is permanent; however the majority fully recover.
Women with Hashimoto’s
thyroiditis and Graves’ disease have an increased
incidence of post-partum thyroiditis, which may recur
with subsequent pregnancies.
Subacute
thyroiditis
In contrast to post-partum
thyroiditis, which is painless, subacute thyroiditis is
painful. It often occurs in conjunction with an upper
respiratory infection but does not resolve as rapidly as
the infection. Women are affected more frequently than
men, most often between the ages of thirty and fifty.
A
person with subacute thyroiditis may experience pain
radiating from the thyroid to the jaw or ear on either
one or both sides of his or her face.
The thyroid gland
may be exquisitely tender in the initial phase, and the
person may experience symptoms of hyperthyroidism (see
above).
The initial hyperthyroid phase is followed by a
hypothyroid phase, which may require treatment with T4.
Approximately 10% of those affected become permanently
hypothyroid. Aspirin and non-steroidal
anti-inflammatory drugs such as ibuprofen may suffice
for the pain.
In more severe cases, steroids are useful. Subacute thyroiditis may recur.
Thyroid Nodules
Thyroid nodules, or
‘lumps’ on the thyroid, are also more common in women
than in men.
The thyroid often functions normally in the
setting of both benign and malignant nodules. Multiple
nodules within the same thyroid gland are generally
benign.
If you have a single thyroid nodule, or one that
is clearly larger than the others, you should have a
fine needle aspiration biopsy
performed, which involves retrieving cells
from the nodule with a thin needle so the cells can be
studied. Benign
(non-cancerous) thyroid nodules
may be followed by observation and suppressive treatment
with T4.
Malignant
(tending to spread)
thyroid nodules should be surgically removed.
Thyroiditis Cancer
Papillary carcinoma
The most common form of
thyroid cancer is papillary carcinoma. Women develop
this disease three times as often as men, and most
people with papillary carcinoma are diagnosed between
the ages of thirty and fifty.
When diagnosed before age
forty, papillary carcinoma is unlikely to be aggressive
and may not alter a person’s lifespan. Following thyroidectomy, thyroid hormone replacement is taken by
the patient.
Radioactive iodine may be administered in
large doses to destroy any remaining thyroid tissue.
Follicular carcinoma
Follicular carcinoma, the
second most common type of thyroid cancer, also affects
women three times more often than men.
The average age
of those who are diagnosed with follicular carcinoma is
sixty, and it tends to be more aggressive than papillary
carcinoma. Follicular carcinoma may metastasize (spread)
to the bones and lungs.
Treatment includes surgical
removal of the thyroid, T4 replacement, radioactive
iodine, and occasionally radiation and chemotherapy if
required.
Conclusion
Thyroid disease occurs
with much greater frequency in women than in men. Many
different organ systems can be affected by the presence
of abnormal levels of thyroid hormone resulting in a
whole host of symptoms.
There are a number of treatments
available for diseases related to the thyroid.
If you
suspect you may be experiencing symptoms similar to the
ones listed above, discuss them with your doctor.
