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Thyroid Disease: What You Need to Know
The thyroid is not a part of the human anatomy most of us think about unless something goes wrong. Thyroid conditions can cause a range of seemingly unrelated problems, including drastic changes in weight, energy, digestion, or mood. The good news is that most thyroid disorders can be managed or even cured with medication, radioactive iodine therapy, or surgery, depending on the type of thyroid condition being treated.
The thyroid is a small, butterfly-shaped gland at the base of the neck that produces thyroid hormone. This hormone controls many of the body’s functions, such as heart rate and how fast calories are burned. Diseases of the thyroid cause it to make either too much or too little of the hormone, causing symptoms such as weight fluctuations, fatigue, and restlessness.
Common types of thyroid disease include thyroid nodules, hypothyroidism and hyperthyroidism, Graves’ disease, goiters, thyroiditis, and thyroid cancer. Women are more likely than men to have thyroid diseases, especially after pregnancy or menopause.
Nearly one in 20 Americans age 12 and older has an underactive thyroid, or hypothyroidism. If the thyroid gland doesn’t produce enough hormones, many body functions will slow down. A smaller number of people — about one in 100 — have an overactive thyroid, called hyperthyroidism. Their thyroids release too much hormone.
Thyroiditis is inflammation in the thyroid that causes stored thyroid hormone to leak from the gland. At first, the leakage increases hormone levels in the blood, leading to hyperthyroidism. This condition may last for up to three months, after which the thyroid may become underactive. The resulting hypothyroidism usually lasts 12-18 months but can be permanent. Sub-acute thyroiditis involves a painfully inflamed and enlarged thyroid, and it may be related to an infection caused by a virus or bacteria. Silent thyroiditis is called that because it is painless, even if the thyroid is enlarged. Research suggests that silent thyroiditis probably is an autoimmune condition.
Thyroid problems are more likely to occur in women or in people over age 60, and having a family history of thyroid disorders also increases the risk. Thyroid conditions often are caused by autoimmune disorders, in which the immune system mistakenly attacks and destroys the body’s own cells. For example, an autoimmune disorder called Graves’ disease can cause the thyroid to be overactive, and a condition called Hashimoto’s disease can make the thyroid underactive.
Thyroid disorders can be hard to diagnose, because the symptoms are similar to other conditions. If a thyroid disorder is suspected — perhaps due to weight changes or fatigue — blood tests can help confirm the diagnosis and find its cause. Thyroid diseases usually are treatable, but they can cause serious problems in other parts of the body if left untreated. During pregnancy, thyroid hormones can affect the health of both the mother and the fetus. Thyroid hormone levels sometimes need to be carefully monitored and adjusted, even if the expectant mother has no history of thyroid problems. After pregnancy, some women have abnormal thyroid hormone levels for a year or more.
The thyroid gland also can be affected by cancer. Thyroid cancer usually has no symptoms, though sometimes it’s first noticed as a lump in the neck, which often may be a harmless nodule. A doctor can determine if a nodule is cancerous by removing and examining a tiny piece of it (a process known as biopsy). If it shows signs of cancer, the nodule or even the entire thyroid will be removed.
Patients with underactive thyroids can be treated with artificial thyroid hormones. Overactive thyroids often are treated with medications that reduce hormone levels.
The aim of hyperthyroidism treatment is to bring thyroid hormone levels back to normal, to prevent long-term health problems and relieve uncomfortable symptoms. No single treatment works for everyone. Medication, radioiodine therapy, or thyroid surgery may be used to treat hyperthyroidism, depending on the cause and severity of the condition, the patient’s age, and possible allergies to (or side effects of) medication.
Medications used to treat hyperthyroidism are called beta blockers. Beta blockers may reduce symptoms until other treatments take effect, quickly relieving (usually within hours) symptoms such as tremors, rapid heartbeat, and nervousness.
Antithyroid therapy, which involves medication to reduce thyroid hormone production, is the simplest treatment, but it does not provide a permanent cure. Health care providers most often use the antithyroid medicine methimazole. During the course of treatment, thyroid hormone levels may not reach the normal range for several weeks or months. The total average treatment time is one to two years, but treatment can continue for longer than that. Antithyroid medicines are not used to treat hyperthyroidism caused by thyroiditis.
Radioiodine therapy, which uses radioactive iodine, is a common and effective treatment for hyperthyroidism. Introduced by capsule or liquid, radioactive iodine-131 slowly destroys the cells of the thyroid gland that produce thyroid hormone. Radioactive iodine does not affect other bodily tissue. Most patients who undergo radioactive iodine treatment later develop hypothyroidism because the thyroid hormone-producing cells have been destroyed. However, hypothyroidism is easier to treat and causes fewer long-term health problems than hyperthyroidism, and the condition can be controlled with daily thyroid hormone medicine.
The least-used treatment for hyperthyroidism is surgery to remove part or most of the thyroid gland. Sometimes doctors use surgery to treat people with large goiters or pregnant women who cannot take antithyroid medicines. After thyroid removal, hormone levels may return to normal. You may still develop hypothyroidism after surgery and need to take thyroid hormone medicine. If your entire thyroid is removed, you will need to take thyroid hormone medicine for life. After surgery, your doctor will continue to check your thyroid hormone levels.
Hypothyroidism is treated by replacing the hormone that your own thyroid can no longer make. Levothyroxine, a thyroid hormone medicine that is identical to a hormone the thyroid normally produces, will assist the body in reaching and maintaining normal hormone levels.
Thyroid disease is treated by the UAB Medicine Division of Endocrinology, Diabetes, and Metabolism, which is consistently recognized for excellence by U.S. News & World Report. Click here to learn more about thyroid care at UAB Medicine.
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