The thyroid gland is a small, gland located in the base of the neck. It plays a huge role in our body, influencing the function of many of the body’s most important organs, including the heart, brain, liver, kidneys and skin.
Think of your thyroid as a car engine that controls how your body functions. An engine produces the necessary energy for a car to operate in a certain manner. In the same way, the thyroid gland produces enough thyroid hormone to prompt your body to perform functions in a certain manner. Just as a car cannot produce energy without gas, your thyroid needs fuel to produce thyroid hormone. Your thyroid’s fuel is iodine. The thyroid extracts iodine from the bloodstream and uses it to make two thyroid hormones: T4 (contains four iodine atoms) and T3 (contains three iodine atoms). T3 is made from T4 when one iodine is removed, a conversion that occurs mostly outside the thyroid in organs and tissues where T3 is the primary thyroid hormone that is used. When T4 is produced, it is stored within the thyroid as a reserve for later use. A small amount of T3 is also produced and stored in the thyroid. When your body needs thyroid hormone, it is secreted into your bloodstream in quantities set to meet the needs of your cells. Your car engine produces energy, but you tell it how fast to go by stepping on the accelerator. The thyroid gets its instruction from the pituitary gland, which is located in your brain. These instructions come in the form of thyroid-stimulating hormone (TSH). TSH levels rise or fall depending on whether enough thyroid hormone is produced to meet your body’s needs. Higher levels of TSH prompt the thyroid to produce more thyroid hormone. Conversely, low TSH levels signal the thyroid to slow down production.
Normally, the thyroid produces just the right amount of hormone to keep your body running smoothly. TSH levels remain fairly constant. But even the best systems are subject to interference. When outside influences such as disease, damage to the thyroid or certain medicines inhibit proper communication, your thyroid might not produce enough hormone. This slows down all of your body’s functions – known as hypothyroidism or underactive thyroid. I like to use the term ‘suboptimal’ thyroid function. Your thyroid could also produce too much hormone which would send your systems into overdrive, a condition called hyperthyroidism or overactive thyroid. I like to use the term overactive thyroid. When considering thyroid disease, doctors ask two main questions: First, is the thyroid gland inappropriately producing an abnormal amount of thyroid hormone? And second, is there a structural change in the thyroid, such as a lump (a nodule) or an enlargement (a goiter)? Though one of these characteristics does not necessarily imply that the other is present nor do they diagnose hypo- or hyperthyroidism.
Sometimes the thyroid can’t meet your body’s demands for thyroid hormone, even though TSH levels increase. As your body slows down, you may feel cold, tired and even depressed. You may gain weight, even though you’re eating less and exercising. There could be a number of reasons why your thyroid is not performing well. For example, if your body isn’t getting enough iodine, your thyroid can’t make enough thyroid hormone, but it will try to respond to rising TSH levels by working harder and harder anyway.
In its earliest stage, hypothyroidism may cause few symptoms, since the body has the ability to partially compensate for a failing thyroid gland by increasing the stimulation to it, much like pressing down on the accelerator when climbing a hill to keep the car going the same speed. As thyroid hormone production decreases and the body’s metabolism slows, a variety of features may result.
Characteristic symptoms and physical signs can signal hypothyroidism. However, the condition may develop so slowly that many patients do not realize that their body has changed, so it is critically important to perform diagnostic laboratory tests to confirm the diagnosis and to determine the cause of hypothyroidism.
Hypothyroidism is generally treated with a daily medication. There are multiple types of thyroid medication. Not everyone respond the same to each medication, and not every medication is appropriate for a particular type of thyroid disease An experienced physician can prescribe the correct form and dosage to return the thyroid balance to normal. Thyroid hormone acts very slowly in some parts of the body, so it may take several months after treatment for some features to improve.
It is extremely important that women planning to become pregnant are kept well adjusted, since hypothyroidism can affect the development of the baby. During pregnancy, thyroid hormone replacement requirements often change, so more frequent monitoring is necessary. Various medications and supplements (particularly iron) may affect the absorption of thyroid hormone; therefore, the levels may need more frequent monitoring during illness or change in medication and supplements. Thyroid hormone is critical for normal brain development in babies.
Since most cases of hypothyroidism are permanent and often progressive, it is usually necessary to treat this condition throughout one’s lifetime. Periodic monitoring of laboratory levels and clinical status are necessary to ensure that the proper dose is being given, since medication doses may have to be adjusted from time to time. Optimal adjustment of thyroid hormone dosage is critical, since the body is very sensitive to even small changes in thyroid hormone levels.
Hyperthyroidism develops when the body is exposed to excessive amounts of thyroid hormone. This disorder occurs in almost one percent of all Americans and affects women five to 10 times more often than men. In its mildest form, hyperthyroidism may not cause recognizable symptoms. More often, however, the symptoms are discomforting, disabling or even life-threatening.
When hyperthyroidism develops, a goiter (enlargement of the thyroid) is usually (but not always) present and may be associated with some or many of the following features:
Characteristic symptoms and physical signs of the disease can be detected by a trained physician. In addition, tests can be used to confirm the diagnosis and to determine the cause.
Two drugs are available for treating hyperthyroidism: propylthiouracil (PTU) and methimazole. Except for early pregnancy, methimazole is preferred. These medications control hyperthyroidism by slowing thyroid hormone production. They may take several months to normalize thyroid hormone levels.
Radioactive Iodine Treatment
Iodine is an essential in the production of thyroid hormone. Each molecule of thyroid hormone contains either four (T4) or three (T3) molecules of iodine. Since most overactive thyroid glands are hungry for iodine, it was discovered that the thyroid could be “tricked” into destroying itself by feeding it radioactive iodine. The radioactive iodine is given by mouth, usually in capsule form. Maximal benefit is usually noted within 3-6 months. Most physicians strive to completely destroy the thyroid gland with a single dose of radioiodine. This results in the intentional development of an underactive thyroid state (hypothyroidism), which is easily, predictably and inexpensively corrected by lifelong daily use of oral thyroid hormone replacement therapy.
Thousands of patients have received radioiodine treatment. The treatment is a very safe, simple and reliably effective. Because of this, it is considered by most thyroid specialists to be the treatment of choice for hyperthyroidism cases caused by overproduction of thyroid hormone.
Surgical Removal of the Thyroid
Although seldom used now as the preferred treatment for hyperthyroidism, surgically removing most(or all) of the thyroid gland may be recommended in certain situations. Surgery usually leads to permanent hypothyroidism and lifelong thyroid hormone replacement therapy.
A drug from the class of beta-adrenergic blocking agents (which decrease the effects of excess thyroid hormone) can temporarily control hyperthyroid symptoms until other therapies take effect. In cases where hyperthyroidism is caused by thyroiditis or excessive ingestion of either iodine or thyroid hormone, this may be the only type of treatment required. Also, iodine drops are prescribed when hyperthyroidism is severe or prior to undergoing surgery for Graves’ disease.
Thyroid disease is more common than diabetes or heart disease. As many as 30 million Americans are affected by thyroid disease – and more than half of those people remain undiagnosed. Women are five times more likely than men to suffer from hypothyroidism.
The thyroid gland produces thyroid hormone, which controls virtually every cell, tissue and organ in the body. Untreated thyroid disease may lead to elevated cholesterol levels and subsequent heart disease, as well as infertility and osteoporosis. Research also shows that there is a strong genetic link between thyroid disease and other autoimmune diseases, including types of diabetes, arthritis and anemia. Simply put, if your thyroid gland isn’t working properly, neither are you.
First, you must recognize the symptoms and risk factors of thyroid disease. Since many symptoms may be hidden or mimic other diseases and conditions, the best way to know for sure is to ask your doctor.
A thyroid nodule is a lump in or on the thyroid gland. Thyroid nodules are common, but are usually not diagnosed. They are detected in about 6% percent of women and 1-2% of men. They are 10 times as common in older people. Sometimes several nodules will develop in the same person. Any time a lump is discovered in thyroid tissue, the possibility of malignancy (cancer) must be considered. Fortunately, the vast majority of thyroid nodules are benign (not cancerous).
Nodules can be caused by a simple overgrowth of “normal” thyroid tissue, fluid-filled cysts, inflammation (thyroiditis), or a tumor (either benign or cancerous).
Most patients with thyroid nodules have no symptoms. Many are found by chance on a routine physical exam or an imaging study of the neck done for unrelated reasons. A substantial number of nodules are first noticed by patients or those they know who see a lump in the front portion of the neck, which may or may not cause symptoms, such as a vague pressure sensation or discomfort when swallowing. Finding a lump in the neck should be brought to the attention of your physician, even in the absence of symptoms.
Most patients who appear to have benign nodules require no specific treatment and can be followed by their physician. Some physicians prescribe thyroid medications with hopes of preventing nodule growth or reducing the size of cold nodules, while radioiodine may be used to treat hot nodules. If cancer is suspected, surgical treatment is recommended. The primary goal of therapy is to remove all thyroid nodules that are cancerous and, if malignancy is confirmed, remove the rest of the thyroid gland along with any abnormal lymph nodes. If surgery is not recommended, it is important to have regular follow-up of the nodule.