The
Human Thyroid is a gland which produces several types of chemicals
known as hormones. The specific hormone which has the major role in
regulating metabolism in the body is called Thyroid Hormone. It is
a major factor in energy level maintenance and is very important in
day to day activity.
Located in the lower neck, it usually is shaped in an H type pattern
with two lobes and a connecting isthmus across the middle. It wraps
around the windpipe below the voicebox and can barely be felt in most
people. The cells which develop into the Thyroid gland originate in
a midline structure during embryologic development before birth. They
migrate down into the lower neck from the remaining tissue which forms
the V shaped tissue region at the back of the tongue. In rare cases,
a child may be found to have a lump in the neck that may be a portion
of undescended thyroid which fell behind along this path. These lumps
are often called Thyroglossal duct cysts. In some cases, the thyroid
gland may begin to have faulty production of the appropriate types
of thyroid hormone. When this occurs, the gland may develop enlargement
throughout both lobes and may enlarge over time. This is commonly
known as a goiter and is found frequently in areas where levels of
dietary iodine, necessary for the production of thyroid hormone, may
be somewhat low. Morton's adds Iodine to our salt to help prevent
goiters.
Most goiters are merely enlargements in the glands size without much
change in shape or texture. In some cases a goiter may become nodular
and have many different lumps of various sizes inside the outer lining
of the thyroid. Multinodular goiters can enlarge to a point where
the size actually begins to cause pressure on the trachea and esophagus.
This can interfere with swallowing and also with breathing. It is
also possible for an enlarging gland to extend downward beneath the
breastbone.
Nodules in the thyroid can also become malignant cancers. These neoplasms
may have the potential to spread throughout the body and can lead
to death. This is the reason that thyroid nodules are carefully checked
by your doctor. Tests to help in determining the type of nodule are
important and may give guidance to the proper type of treatment. For
each malignant lesion found, several hundred benign nodules are evaluated.
But, if a thyroid cancer is discovered early, it may be completely
curable by surgery or by radioactive iodine radiation therapy.
After identifying a potential thyroid nodule, your doctor will order
thyroid blood testing as well as a sonar ultrasound scan of the neck.
A nuclear radioactive scan may also be ordered. In some cases, the
CT or CAT scan may be ordered to evaluate the thyroid and other tissues
in the neck. There are a few special thyroid blood tests that are
also ordered in certain cases. These may provide marker evidence for
lesions which may be suspicious for malignancy. A biopsy performed
with a very thin needle to collect a few cells from the suspicious
nodule may also be ordered. Usually the surgeon will want to perform
this test and often only after the initial imaging is completed. This
biopsy is a bit uncomfortable but may help your doctors to consider
nonsurgical treatments. The results may be clearly positive, vague
and suggestive, or lacking in identifiable material making them of
no value in achieving a diagnosis. The biopsy pulls blood and some
cells from the gland and the surgeon spreads those onto microscopic
slides to allow a cytopathologist to look at the material under the
microscope.
If the behavior of a thyroid nodule continues to be worrisome, your
doctor or doctors may recommend surgery to remove part or all of the
gland. Thyroid medical problems are managed by many types of doctors.
Your family doctor or internist may consult with an endocrinologist
who specializes in hormone types of medical treatment. These doctors
often help patients with thyroid disorders, diabetes, and sex hormone
problems as well.
Treatments for thyroid problems will often require daily thyroid hormone
medication. This may be prescribed to prevent the further enlargement
of a goiter or probably benign thyroid mass. It will also almost always
be prescribed at some point after thyroid surgery. Inadequate thyroid
hormone blood levels can cause fatigue and may cause dry skin and
hair. Changes in muscle reflexes may also be noted. High levels of
thyroid hormone can cause hyperactivity and also bulging of the eyes.
Surgery for thyroid nodules is complicated. Controversy exists regarding
the best type of surgery to offer for an individual patient. In cancer
cases, the total thyroidectomy is usually best. Because the tissue
of the thyroid is so delicate, the appearance with frozen section
biopsies may not be the same as the final appearance with the traditional
type of biopsy stains. Frozen sections are used to make a quick judgement
in the few minutes during an operation, while the traditional stained
technique may take over 24 hours to achieve a final report. If the
reports conflict and the final report demonstrates a cancer that could
not be clearly identified on frozen section, the surgeon may need
to recommend another thyroid surgery known as a completion thyroidectomy.
This is done when the first procedure was performed in a conservative
fashion to try and spare at least part of one of the lobes of the
gland. This is done to attempt to minimize the possibility of complications.
Even in properly done thyroid surgery complications may still arise.
The gland may conceal one or more parathyroid gland within the thyroid
tissue. The parathyroid glands are of a different type of tissue and
are responsible for regulating parathyroid hormone levels. Calcium
is regulated into and out of the bones and the muscles and the blood
by the parathyroid hormone. If these glands, sometimes 4 sometimes
2 sometimes 6 or 7, are all removed with the thyroid tissue, the patient
may quickly develop a drop in blood calcium levels which can cause
severe muscle problems and may cause muscle cramps and may cause heart
problems as well. For this reason, surgical procedures on the thyroid
will often require a surgical search for parathyroid glands in an
attempt to preserve these glands during the thyroid removal.
Voice changes may occur with some types of thyroid disorders. Abnormal
thyroid hormone levels may cause a deepening and a gravelly quality
to the voice. Thyroid surgery may also cause voice changes. It is
not unusual to have a bit of hoarseness for a day or two from the
endotracheal tube which is placed through the vocal cords to protect
the trachea and airway from secretions during surgery. This can cause
some short-term swelling and hoarseness. The recurrent laryngeal nerve
carries the electrical signals to the voicebox to produce the movement
in the vocal cords. These nerves usually pass immediately beneath
the thyroid lobe in the grove of tissue between the trachea and the
esophagus on their way to the voicebox. In some instances, the nerve
may pass directly through the gland itself. If this occurs in a situation
suspicious for cancer, the surgeon may be forced to cut the nerve
to prevent recurrence of the cancer. Merely preserving the nerve by
carefully dissecting tissue off of it may cause swelling in the nerve
and may cause a change in the voice. Usually, when hoarseness follows
thyroid surgery, the swelling subsides in a few days and the hoarseness
subsides and the voice improves. If the nerve is cut, the voice may
not improve without other special procedures. It may require months
of observation to determine whether voicebox activity may return.
The superior laryngeal nerve may also be stretched with thyroid surgery.
This can cause a change in the singing voice. That may not really
be a problem for most patients, but the professional musician or thespian
may need to be aware that such changes could be a result of thyroid
surgery.
Infection in the neck and bleeding may be unexpected problems associated
with thyroid surgery in the neck. Swallowing difficulties are common
after removal of thyroid masses, which have pressed on the esophagus.
Scarring is also a frequent problem with some patients. The thyroid
incision is usually made just above the notch in the sternum or breastbone
and is frequently cut from the right side to the left. Often this
can be placed in a lower neck wrinkle line and may fade without being
very noticeable.
The thyroid procedure can be difficult and may last from 1 to 3 or
4 hours. Most thyroid surgery patients should expect to stay in the
hospital bed over night. Many may stay for several days. Swelling
and oozing in the wound area are expected. Many thyroid patients may
be back to nonstrenuous work duties in 4 or 5 days after surgery.
Most surgeons will ask that a patient return in 1 week and again in
about 1 month. After healing is complete, the surgeon may recommend
that follow-up be continued with an internist or with an endocrinologist.
In cancer cases, the surgeon may suggest frequent follow-up with multiple
doctors for several years. |
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