What is the thyroid gland?
The thyroid gland is a small, butterfly-shaped gland located in the base of the neck just below the Adam’s apple. Although relatively small, the thyroid gland influences the function of many of the body’s most important organs, including the heart, brain, liver, kidneys and skin. Ensuring that the thyroid gland is healthy and functioning properly is important to the body’s overall well- being.
Signs & Symptoms
Hyperthyroidism
When hyperthyroidism develops, a goiter (enlargement of the thyroid) is usually present and may be associated with some or many of the following features:
- Fast heart rate, often more than 100 beats per minute
- Becoming anxious, irritable, argumentative
- Trembling hands
- Weight loss, despite eating the same amount or even more than usual
- Intolerance of warm temperatures and increased likelihood to perspire
- Loss of scalp hair
- Tendency of fingernails to separate from the nail bed
- Muscle weakness, especially of the upper arms and thighs
- Loose and frequent bowel movements
- Smooth skin
- Change in menstrual pattern
- Increased likelihood for miscarriage
- Prominent “stare” of the eyes
- Protrusion of the eyes, with or without double vision (in patients with Graves’ disease)
- Irregular heart rhythm, especially in patients older than 60 years of age
- Accelerated loss of calcium from bones, which increases the risk of osteoporosis and fractures
Hypothyroidism
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.
- Pervasive fatigue
- Drowsiness
- Forgetfulness
- Difficulty with learning
- Dry, brittle hair and nails
- Dry, itchy skin
- Puffy face
- Constipation
- Sore muscles
- Weight gain and fluid retention
- Heavy and/or irregular menstrual flow
- Increased frequency of miscarriages
- Increased sensitivity to many medications
Hashimoto’s Thyroiditis
Hashimoto’s thyroiditis may not cause symptoms for many years and remain undiagnosed until an enlarged thyroid gland or abnormal blood tests are discovered as part of a routine examination. When symptoms do develop, they are either related to local pressure effects in the neck caused by the goiter itself, or to the low levels of thyroid hormone. The first sign of this disease may be painless swelling in the lower front of the neck. This enlargement may eventually become easily visible. It may be associated with an uncomfortable pressure sensation in the lower neck. This pressure on surrounding structures may cause additional symptoms, including difficulty swallowing.
Although many of the features associated with thyroid hormone deficiency occur commonly in patients without thyroid disease, patients with Hashimoto’s thyroiditis who develop hypothyroidism are more likely to experience the following:
- Fatigue
- Drowsiness
- Forgetfulness
- Difficulty with learning
- Dry, brittle hair and nails
- Dry, itchy skin
- Puffy face
- Constipation
- Sore muscles
- Weight gain
- Heavy menstrual flow
- Increased frequency of miscarriages
- Increased sensitivity to many medications
The thyroid enlargement and/or hypothyroidism caused by Hashimoto’s thyroiditis progresses in many patients, causing a slow worsening of symptoms. Therefore, patients with either of these findings should be recognized and adequately treated with thyroid hormone. Optimal treatment with thyroid hormone will eliminate any symptoms due to thyroid hormone deficiency, usually prevent further thyroid enlargement, and may sometimes cause shrinkage of an enlarged thyroid gland.
Thyroid Nodule
Most patients with thyroid nodules have no symptoms whatsoever. Many are found by chance to have a lump in the thyroid gland on a routine physical exam or an imaging study of the neck done for unrelated reasons (CT or MRI scan of spine or chest, carotid ultrasound, etc.). In addition, a substantial number 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. Obviously, finding a lump in the neck should be brought to the attention of your physician, even in the absence of symptoms.
Family History
A familiar place to look for thyroid disorder signs and symptoms is your family tree. If you have a first degree relative (a parent, sibling, or child) with thyroid disease, you would benefit from thyroid evaluation. Women are more prominent thyroid patients than men; however, the gene pool runs through both.
According to a national survey by the American Association of Clinical Endocrinologists (AACE), more than three-fourths (76%) of the population do not know that thyroid disease runs in families.
Other Reasons to Consider a Thyroid Evaluation
Prescription Medications
If you are taking Lithium, Amiodarone, Antithyroid drugs (either PTU or Tapazole), or Levothyroxine, you should consider a thyroid evaluation.
Radiation Therapy to the Head or Neck
If you have had any of the following radiation therapies, you should consider a thyroid evaluation: radiation therapy for tonsils, radiation therapy for an enlarged thymus, or radiation therapy for acne.
Chernobyl
If you have leaved near Chernobyl at the time (1986) of the nuclear accident, you should consider a thyroid evaluation.
Conditions
Hyperthyroidism
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 ten 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.
Hypothyroidism
Hypothyroidism (underactivity of the thyroid gland) occurs when the thyroid gland produces less than the normal amount of thyroid hormone. The result is the “slowing down” of many bodily functions. Although hypothyroidism may be temporary, it usually is a permanent condition. Of the nearly 25 million people suffering from a thyroid condition, most have hypothyroidism.
Hashimoto’s Thyroiditis
Hashimoto’s thyroiditis (also called autoimmune or chronic lymphocytic thyroiditis) is the most common thyroid disease in the United States. It is an inherited condition that affects approximately 14 million Americans and is about seven times more common in women than in men. Hashimoto’s thyroiditis is characterized by the production of immune cells and autoantibodies by the body’s immune system, which can damage thyroid cells and compromise their ability to make thyroid hormone. Hypothyroidism occurs if the amount of thyroid hormone, which can be produced, is not enough for the body’s needs. The thyroid gland may also enlarge, forming a goiter.
Thyroid Nodules
The thyroid gland is located in the lower front of the neck, above the collarbones, and below the voice box (larynx). 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 six percent of women and one to two percent of men. They are 10 times as common in older individuals than in younger ones. 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).
Treatment
Hyperthyroidism
Before the development of current treatment options, the death rate from severe hyperthyroidism was as high as 50 percent. Now several effective treatments are available and, with proper management, death from hyperthyroidism is rare. Deciding which treatment is best depends on what caused the hyperthyroidism, its severity, and other conditions present. A physician who is experienced in the management of thyroid diseases can confidently diagnose the cause of hyperthyroidism and prescribe and manage the best treatment program for each patient.
Antithyroid Drugs
In the United States, two drugs are available for treating hyperthyroidism: propylthiouracil (PTU) and methimazole (Tapazole). These medications control hyperthyroidism by slowing thyroid hormone production, and are frequently used for several months after the initial diagnosis of hyperthyroidism to normalize the thyroid hormone levels. Some patients with hyperthyroidism caused by Graves’ disease experience a spontaneous or natural remission of hyperthyroidism after a 12- to 18-month course of treatment with these drugs, and may sometimes avoid permanent underactivity of the thyroid (hypothyroidism), which often occurs as a result of using the other methods of treating hyperthyroidism. Unfortunately, the remission is frequently only temporary, with the hyperthyroidism recurring after several months or years off medication and requiring additional treatment, so relatively few patients are treated solely with antithyroid medication in the United States.
Antithyroid drugs may cause an allergic reaction in about five percent of patients who use them. This usually occurs during the first six weeks of drug treatment. Such a reaction may include rash or hives; but after discontinuing use of the drug, the symptoms resolve within one to two weeks and there is no permanent damage.
A more serious effect, but occurring in only about one in 250-500 patients during the first four to eight weeks of treatment, is a rapid decrease of white blood cells in the bloodstream. This could increase susceptibility to serious infection. Symptoms such as a sore throat, infection, or fever should be reported promptly to your physician, and a blood cell count should be done immediately. In nearly every case, when a person stops using the medication, the white blood cell count returns to normal. Very rarely, antithyroid drugs may cause severe liver problems, which can be detected by monitoring blood tests or joint problems characterized by joint pain and/or swelling. Your physician should be contacted if there is yellowing of the skin (“jaundice”), fever, loss of appetite, or abdominal pain.
Radioactive Iodine Treatment
Iodine is an essential ingredient 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 quite hungry for iodine, it was discovered in the 1940’s that the thyroid could be “tricked” into destroying itself by simply feeding it radioactive iodine. The radioactive iodine is given by mouth, usually in capsule form, and is quickly absorbed from the bowel. It then enters the thyroid cells from the bloodstream and gradually destroys them. Maximal benefit is usually noted within three to six months.
It is not possible to eliminate “just the right amount” of the diseased thyroid gland, since radioiodine eventually damages all thyroid cells. Therefore, most endocrinologists strive to completely destroy the diseased 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. Although every effort is made to calculate the correct dose of radioiodine for each patient, not every treatment will successfully correct the hyperthyroidism, particularly if the goiter is quite large and a second dose of radioactive iodine is occasionally needed.
Thousands of patients have received radioiodine treatment, including former President of the United States George Bush and his wife, Barbara. The treatment appears to be a very safe, simple, and reliably effective one. Because of this, it is considered by most thyroid specialists in the United States to be the treatment of choice for hyperthyroidism cases caused by overproduction of thyroid hormone.
Surgical Removal of the Thyroid
Operating to remove most of the thyroid gland may occasionally be recommended in certain situations, such as a pregnant woman with severe uncontrolled disease in whom radioiodine would not be safe for the baby. Surgery usually leads to permanent hypothyroidism and lifelong thyroid hormone replacement therapy.