January is recognized as Thyroid Awareness Month to help people learn about thyroid-related diseases and cancer. Dr. Beatriz DeMoranville, board-certified in endocrinology, diabetes and metabolism and an endocrinologist for Care New England Health System, spoke with Providence Business News about thyroid illnesses.
PBN: What are the most common types of thyroid-related diseases?
DeMoranville: The thyroid is a gland that produces, stores and releases thyroid hormones. It is located in the neck, below the Adam’s apple, and has a butterfly shape. Thyroid hormones control the speed of the body’s metabolism, which relates to the amount of energy consumed by the multiple organs of the body to function properly. These hormones require iodine to be produced. The thyroid hormones are thyroxine (T4) and triiodothyronine (T3). The hormone levels are regulated by the pituitary gland and hypothalamus in the brain via a feedback system.
In hypothyroidism (underactive thyroid), thyroid hormones are deficient, and the metabolism is slow, leading to weight gain, fatigue, somnolence, cold intolerance, constipation, dry skin and fatigue, among other problems.
In hyperthyroidism (overactive thyroid), there is an overproduction or release of too much thyroid hormone, leading to abnormally high energy consumption that leads to unexplained weight loss, heat intolerance, rapid heartbeat, sweating, diarrhea, insomnia, irritability, tremors and other abnormal body functions.
Other thyroid disorders that involve structural abnormalities include enlarged thyroid glands, also known as goiters, thyroid nodules and thyroid cancer.
PBN: What causes these illnesses?
DeMoranville: The most common cause of hypothyroidism in the world is iodine deficiency. Patients with iodine deficiency usually present with a goiter, given the need to store iodine in a larger volume. According to public health experts, iodization of salt may be the world's simplest and most cost-effective measure available to prevent hypothyroidism. That is why iodized table salt is widely available in the U.S. The FDA [Food and Drug Administration] recommends a daily intake of 150 micrograms (0.15 mg) of iodine for adults. Excessive iodine intake is not advised, as it may precipitate hypo- or hyperthyroidism.
In the United States, the most common cause of hypothyroidism is autoimmune thyroid disease. The condition is also known as Hashimoto’s thyroiditis. This happens when antibodies attack and damage the thyroid gland, making it underactive. Other causes of hypothyroidism include congenital hypothyroidism, in which the individual is born without a thyroid gland, and surgical hypothyroidism, following the removal of the thyroid.
The autoimmune cause of hyperthyroidism is called Graves’ disease, in which specific antibodies overstimulate the production of thyroid hormone and may present with an enlarged and swollen thyroid gland besides the symptoms of hyperthyroidism described earlier. Some patients with Graves’ disease also present with protrusion and congestion of eyes, also known as thyroid eye disease, or TED.
Thyroid nodules are relatively common and can be found in more than half of the population (60%). Most thyroid nodules do not interfere with thyroid function. Most of them are benign nodules. Some of these benign nodules may produce too much thyroid hormone and cause hyperthyroidism. Some thyroid nodules (5-15%) may harbor cancer cells or become cancerous, leading to thyroid cancer.
Other causes of thyroid disease include thyroiditis, which consists of swelling and inflammation of the thyroid gland by viruses, bacterial infections or radiation; and medications, such as lithium and amiodarone, which precipitate thyroid disease via multiple mechanisms.
PBN: How can thyroid-related diseases be prevented?
DeMoranville: In most of the world, iodine deficiency is the most common cause of hypothyroidism and goiters. That is why in the USA there is iodized table salt widely available, and we do not see as many people with large goiters. On the other hand, excessive amounts of iodine may precipitate both hyperthyroidism and hypothyroidism, so that must be avoided. We also recommend maintaining a balanced diet and lifestyle to prevent stress and autoimmune diseases. Other conditions are not preventable, as they are precipitated by unforeseen triggering factors.
PBN: What are the treatment options for thyroid diseases and cancer?
DeMoranville: Hypothyroidism is treated with thyroid hormone replacement. Most medications available are synthetic forms of thyroid hormones – levothyroxine, liothyronine. There are also preparations made from dried thyroid glands of animals (desiccated thyroid) that contain thyroid hormones. The goal is to normalize the thyroid hormone levels and restore well-being.
Hyperthyroidism is treated with medications that slow down and control the production of thyroid hormones. The doses are adjusted and monitored to maintain normal levels without side effects from the medications. Other treatment options include radioactive iodine ablation treatment, which causes radiation damage to the thyroid cells, and thyroidectomy – removal of the hyperthyroid gland. In both cases, the patient will become hypothyroid, so the procedures are followed by thyroid hormone replacement.
If the patient is diagnosed with thyroid cancer, the thyroid is surgically removed (thyroidectomy). If the cancer is confined, only the lobe that contains the cancer needs to be removed. If the cancer is more advanced and has high risk of recurrence, it requires a total thyroidectomy followed by radioactive iodine therapy at high doses to eliminate any cancer cells remaining in the thyroid bed or that might have metastasized. This is followed by thyroid hormone replacement and surveillance for at least five years.
PBN: Is there a cure for these illnesses?
DeMoranville: Except for iodine deficiency, which can be corrected with the proper ingestion of iodine, there is no cure for these illnesses. However, they can be treated. Most patients have normal and healthy lives with the proper treatment and follow-up.
Katie Castellani is a PBN staff writer. You may contact her at Castellani@PBN.com.