The thyroid gland is an important organ of the human body that helps regulate many functions, with the most important function being to regulate the basic metabolic rate of the body. The gland is positioned in the anterior neck, just below the cartilages of the voice box, commonly known as the Adam’s apple. It is comprised of two halves, referred to as lobes, on the left and right side.
The thyroid gland can have different problems that require medical evaluation and treatment. The problems typically involve making too much or too little thyroid hormone, the gland becoming enlarged (known as a goiter), the development of benign thyroid nodules, or the development of thyroid cancer. These disorders are often treated by an endocrinologist or a thyroid surgeon.
Many problems of the thyroid gland, including developing thyroid cancer, have a genetic predisposition and often run in families. It is not uncommon to see patients with a thyroid abnormality and note that many family members also have thyroid problems.
A patient that has low levels of thyroid hormone (hypothyroidism) can have many symptoms, with the most common being generalized fatigue, unexpected weight gain, cold intolerance, and dry coarse skin and hair. A patient with high levels of thyroid hormone (hyperthyroidism) also have many symptoms. The most common symptoms of hyperthyroidism include unexplained weight loss, rapid heart rate, weakness, and heat intolerance. Both of these disorders have many causes and are often diagnosed with blood tests. These patients are usually managed medically, very rarely requiring thyroid surgery.
When the thyroid gland becomes enlarged, it is known as a thyroid goiter. There are many causes, but the most common cause worldwide is due to low levels of iodine in the diet. However, this is not the case in the U.S. and other developed countries as there is sufficient amounts of iodine in our diet. A more common cause in the U.S. is due to elevated levels of TSH, a hormone that causes the thyroid gland to enlarge. This can be treated by thyroid medication, but the patient may need surgery in the form of a total (or subtotal) thyroidectomy. The reason most patients require the surgery is due to the compression on vital structures (blood vessels, etc) the goiter places.
Thyroid nodules, or masses, are another common problem of the thyroid gland. These are typically noted by the patient or the primary care physician upon palpation of the neck, or maybe found upon imaging studies incidentally (for example, finding a thyroid nodule on a carotid artery exam). The vast majority (over 90%) of thyroid nodules are benign, with the exception of these nodules being a malignant cancer. The evaluation of a nodule includes an ultrasound of the gland, as well as a biopsy. The least invasive technique to obtain a biopsy is using a needle (referred to as a FNA, fine needle aspiration). This technique is very accurate and important for patient management. Benign nodules may be observed, but lesions that are worrisome for cancer will need surgical removal.
There are 4 main types of thyroid cancer. The most common type is papillary carcinoma, and the next most common type is follicular carcinoma. Both of these are treated with thyroid surgery, often requiring the complete removal of the gland (total thyroidectomy). Some patient will need radioactive-iodine treatments following the surgery as well. The survival rate is excellent for both of these types of cancer when treated appropriately, with most studies showing the cure rates being over 90%. The other types of thyroid cancer, medullary and anaplastic carcinoma, are not common and often require additional surgery and medical therapy (possible chemotherapy or radiation therapy). Despite these additional treatments, medullary and anaplastic thyroid cancer have a much poorer prognosis when compared to the papillary and follicular variants.
Thyroid surgery is performed with general anesthesia and typically takes 2-4 hours. Patients may or may not need hospital admission following the surgery. There is moderate pain afterwards, and many patients notice a transient change in the voice with mild trouble swallowing. Patients may have a transient decrease in calcium levels and require replacement. Approximately 1% of patient may have a permanent injury to the nerve that moves a vocal fold, causing paralysis of the vocal fold. This would result in hoarseness, and potentially require a future surgery to help correct the cord paralysis. If the entire gland is removed, then the patient will need to take thyroid replacement medication daily for the rest of their life. Most patients that only require a partial thyroidectomy will not need any thyroid medication following the surgery as the remaining portion of the gland is usually sufficient to produce an adequate amount of thyroid hormone.
The thyroid gland is prone to several problems, which can be treated with both medical and surgical therapies. Otolaryngologists play an important role in detecting these problems, as well as caring for patients with thyroid disease.
Robert Wilson, MD.