The thyroid gland, located at the base of the neck, produces hormones that regulate metabolism, heart rate and body temperature. Every cell in the body depends on the thyroid hormones. The thyroid gland is prone to several disorders:
Hyperthyroidism, or overactive thyroid, occurs when the thyroid makes too much thyroid hormone. The most common cause of hyperthyroidism is Graves Disease, an autoimmune disease that makes the thyroid make excess hormone. Other causes include thyroid nodules, inflammation of the thyroid, consuming too much iodine and too much synthetic thyroid hormone, which is used to treat underactive thyroid. Symptons include:
- Being nervous or irritable
- Mood swings
- Fatigue or muscle weakness
- Heat intolerance
- Trouble sleeping
- Hand tremors
- Rapid and irregular heartbeat
- Frequent bowel movements or diarrhea
- Weight loss
- Goiter, which is an enlarged thyroid that may cause the neck to look swollen
Once diagnosed, hyperthyroidism can be treated with antithyroid medicines, radioactive iodine to destroy the thyroid gland and/or surgical removal. If the thyroid is removed or destroyed, patients must take thyroid hormone replacement pills.
Hypothyroidism is defined as an underactive thyroid. Women are more commonly diagnosed with hypothyroidism, which can be caused by the autoimmune disorder Hashimoto's disease, thyroid nodules, thyroiditis, congenital hypothyroidism, surgical removal or radiation treatment of the thyroid. Symptons inlcude:
- Weight gain
- A puffy face
- Cold intolerance
- Joint and muscle pain
- Dry skin
- Dry, thinning hair
- Decreased sweating
- Heavy or irregular menstrual periods and fertility problems
- Slowed heart rate
Hypothyroidism can be controlled with a daily dose of synthetic thyroid hormone.
Goiter is often caused by a diet deficient in iodine and is not common in the United States of America. When goiter does occur among Americans, a more common cause is an increase in thyroid stimulating hormone (TSH) that is a result of hypothyroidism. This condition may be medically managed by providing thyroid hormone in the form of a pill.
Patients may be referred for surgery if the goiter continues to grow, especially if it begins to compress on other structures in the neck such as the trachea and esophagus. Although the incidence for cancer is small, surgery would be recemmended if it is suspected.
Nodules, which can often be felt as a lump in the neck, may occur within the thyroid gland. More than 90 percent of all thyroid nodules are benign (non-cancerous) growths.
Risk factors for thyroid cancer include exposure to radiation (including previous treatment for head and neck cancers), personal or family history of goiter (enlarged thyroid) and certain inherited genetic syndromes. In addition to a lump in the neck, symptoms may include changes to the voice, difficulty swallowing and pain in the neck and throat. Patients may also have swollen lymph nodes in the neck.
Physicians diagnose thyroid cancer in a number of ways, including a physical exam, blood tests to measure levels of thyroid stimulating hormone, a fine needle biopsy to examine cells in the thyroid and imaging tests such as a thyroid ultrasound.
Some patients who have cancerous nodules can undergo is a minimally invasive, video-assisted thyroidectomy. In this procedure, surgeons use an endoscope to remove all or part of the thyroid. Some patients may also have radioactive iodine treatments (or internal radiotherapy) after their surgery.
Parathyroid glands are four small glands in the neck that make a hormone that helps regulate the level of calcium in the body. Disorders of the parathyroid include:
Hyperparathyroidism is a common disease of the parathyroid gland caused by overactivity of one or more of the parathyroid glands. As a result, the glands make too much of the parathyroid hormone and can cause a serious calcium imbalance. Hyperparathyroidism can be caused by tumors that elevate the level of parathyroid hormone, which then causes a rise in the level of Ca2+ (calmodulin-dependent protein kinase) in the blood, at the expense of calcium stores in the bones. Over time, patients may develop osteopenia, in which the bones become brittle and there is an increased risk of fracture.
Treatment for hyperparathyroidism involves the removal of the abnormal gland or glands. In about 90 percent of cases, only one of the four glands has been affected by a benign tumor and that gland is the only one that is hypersecreting. This condition is called parathyroid adenoma.
In only about 10 percent or fewer cases, patients with hyperparathyroidism have had all four glands grow large (hyperplasia) and secrete too much parathyroid hormone (PTH). This condition is called parathyroid hyperplasia.
A parathyroid adenoma is a noncancerous (benign) tumor found in the parathyroid glands, and can be caused by a genetic problem. The most common cause of parathyroid adenoma is hyperparathyroidism, which leads to increased blood calcium levels.
There is a rare cancer that sometimes forms in tissues of one or more parathyroid glands. That cancer can be treated with surgery and/or radiation therapy. Surgeons at GW Hospital offer minimally invasive parathyroidectomy, with and without video assistance. In the video-assisted surgery, physicians use targeted incisions and endoscopes to provide more precise localization of parathyroid tumors and remove the affected gland.
When patients have hyperplasia, in which all four glands are enlarged, all hypersecreting glands are typically removed surgically. Then, part of one gland is either re-implanted in a muscle in neck or forearm, or part of one gland is left in place if it is not enlarged.