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Hyperthyroidism

Hyperthyroidism

Definition

Hyperthyroidism is the overproduction of thyroid hormones by an overactive thyroid gland.

Description

Located in the front of the neck, the thyroid gland produces the hormones thyroxine (T4) and triiodothyro-nine (T3) that regulate the body's metabolic rate by helping to form protein ribonucleic acid (RNA) and increasing oxygen absorption in every cell. In turn, the production of these hormones is controlled by a thyroid-stimulating hormone (TSH) that is produced by the pituitary gland. When production of the thyroid hormones increases despite the level of TSH being produced, hyperthyroidism occurs. The excessive amount of thyroid hormones in the blood increases the body's metabolism, creating both mental and physical symptoms.

The term hyperthyroidism covers any disease that results in an overabundance of thyroid hormone. Other names for hyperthyroidism, or specific diseases within the category, include Graves' disease, diffuse toxic goiter, Basedow's disease, Parry's disease, and thyrotoxicosis. Hyperthyroidism affects 2.5 million people in the United States, but could affect up to 4.5 million people because more than half of the people with thyroid disease don't know they have it. Although it occurs at all ages, hyperthyroidism is most likely to occur after the age of 15. There is a form of hyperthyroidism called neonatal Graves' disease, which occurs in infants born of mothers with Graves' disease. Occult hyperthyroidism may occur in patients over age 65 and is characterized by a distinct lack of typical symptoms. Diffuse toxic goiter occurs in as many as 80% of patients with hyperthyroidism.

Causes & symptoms

Hyperthyroidism is often associated with the body's production of auto-antibodies in the blood that cause the thyroid to grow and secrete excess thyroid hormone. This condition, as well as other forms of hyperthyroidism, may be inherited. Regardless of the cause, hyperthyroidism produces the same symptoms, including weight loss with increased appetite, shortness of breath and fatigue, intolerance to heat, heart palpitations (strong, very fast heartbeats), increased frequency of bowel movements, weak muscles, tremors, anxiety , and difficulty sleeping. Women also may notice decreased menstrual flow and irregular menstrual cycles.

Patients with Graves' disease often have a goiter (visible enlargement of the thyroid gland), although as many as ten percent do not. These patients also may have bulging eyes. Thyroid storm, a serious form of hyperthyroidism, may show up as sudden and acute symptoms, some of which mimic typical hyperthyroidism but with the addition of fever , substantial weakness, extreme restlessness, confusion, emotional swings or psychosis, and perhaps even coma.

Diagnosis

Physicians will look for physical signs and symptoms indicated by patient history. On inspection, the physician may note symptoms such as a goiter or eye-bulging. Other symptoms or family history may be clues to a diagnosis of hyperthyroidism. An elevated basal (lowest range of normal) body temperature above 98.6 degrees Fahrenheit (37 degrees centigrade) may be an indication of a heightened basal metabolic rate (which measures the energy used to maintain vitality) and hyperthyroidism. A simple blood test can be performed to determine the amount of thyroid hormone in the patient's blood. The diagnosis usually is straightforward with this combination of clinical history, physical examination, and routine blood hormone tests. Radioimmunoassay, or a test to show concentrations of thyroid hormones with the use of a radioisotope (a chemical element capable of radioactive or atomic transformations) mixed with fluid samples, helps confirm the diagnosis. A thyroid scan is a nuclear medicine procedure involving injection of a radioisotope dye that will tag the thyroid and help produce a clear image of inflammation or involvement of the entire thyroid.

Other tests can determine thyroid function and thyroid-stimulating hormone levels. Ultrasonography (a test whereby high-frequency sound waves (ultrasound) are bounced off tissues and echoes are converted to pictures (sonograms), computed tomography or (CT) scan (an x-ray computer procedure that produces a detailed picture of a cross-section of the body), and magnetic resonance imaging (MRI) (an x-ray technique that produces a detailed image of the inner body using a powerful magnet, radio waves, and a computer) may provide visual confirmation of a diagnosis or help to determine the extent of involvement.

Treatment

Alternative treatments for hyperthyroidism include nutritional therapy, herbal therapy, and homeopathy , the use of tiny doses of diluted and harmless remedies to catalyze healing.

Nutritional therapy

Consumption of such foods as broccoli, Brussels sprouts, cabbage, cauliflower, kale, rutabagas, spinach, turnips, peaches, and pears can help naturally suppress thyroid hormone production. Dairy products and any stimulants such as tea, coffee, soda, and other caffeinated drinks should be avoided. Under the supervision of a trained physician, high dosages of certain vitamin/mineral combinations can help alleviate hyperthyroidism.

Homeopathy

An experienced homeopath may give patients specific remedies tailored to their overall personality profile as well as their specific symptoms. Symptomatic treatments may include Iodium or Natrum muriaticum.

Other therapies

Other alternative treatments that may help relieve hyperthyroidism symptoms include traditional Chinese medicine and Western herbal medicine. Stress reduction techniques such as meditation also may prove beneficial. Patients should contact experienced herbalists for specific preparations and treatment.

Allopathic treatment

Allopathy is the theory or system of medical practice that combats disease by use of remedies that produce

SYMPTOMS OF HYPERTHYROIDISM
Symptoms
Goiter
Weight loss with increased appetite
Trembling hands
Heightened blood pressure
Excessive nervousness
Increased bowel movements
Accelerated heart rate

effects different from those produced by the disease. Treatment will depend on the specific disease and individual circumstances such as age, severity of disease, and other conditions affecting a patient's health.

Antithyroid drugs

Antithyroid drugs often are administered to help the patient's body cease overproduction of thyroid hormones. In 2004, some drugs used to interfere with the thyroid gland's uptake of iodine were propylthiouracil (PTU) and methimazole (Tapazole®). Medication may work for young adults, pregnant women, and others. Women who are pregnant should be treated with the lowest dose required to maintain thyroid function in order to minimize the risk of hypothyroidism (underactive thyroid gland function) in the infant.

Radioactive iodine

Radioactive iodine often is prescribed to damage cells that make thyroid hormone. The cells need iodine to make the hormone, so they will absorb any iodine found in the body. The patient may take an iodine capsule daily for several weeks, resulting in the eventual shrinkage of the thyroid, reduced hormone production, and a return to normal blood levels. A single large oral dose of radioactive iodine simplifies treatment but should only be given to patients who are not of reproductive age or are not planning to have children, since a large amount can concentrate in the reproductive organs (gonads).

Surgery

Patients treated with thyroidectomy, or surgery involving of partial or total removal of the thyroid, most often suffer from large goiter and have suffered relapses, even after repeated attempts to address the disease through drug therapy with iodine. Following thyroidectomy or iodine therapy, patients must be carefully monitored for years to watch for signs of hypothyroidism, or insufficient production of thyroid hormones. Hypothyroidism can occur as a complication of thyroid production suppression.

Expected results

Hyperthyroidism generally is treatable and carries a good prognosis. Most patients lead normal lives with proper treatment. The majority of patients who receive radioactive iodine report feeling better within about three to six weeks of treatment. Thyroid storm, however, can be life-threatening and can lead to heart, liver, or kidney failure. Some patients who undergo radioactive iodine treatment or surgery become hypothyroid.

Prevention

There are no known prevention methods for hyperthyroidism, since its causes are either inherited or not completely understood. The best prevention tactic is knowledge of family history and close attention to symptoms and signs of the disease. Careful attention to prescribed therapy can prevent complications of the disease.

Resources

BOOKS

The Burton Goldberg Group. Alternative Medicine. Puyallup, WA: Future Medicine Publishing Inc., 1994.

Zand, Janet, Allan N. Spreen, and James B. LaValle. "Hyperthyroidism." Smart Medicine for Healthier Living. Garden City Park, NY: Avery Publishing Group, 1999.

PERIODICALS

Lazarus, John H. "Hyperthyroidism." The Lancet 340 (February 1, 1997): 339342.

"Thyroid Disorders; Facts to Know." NWHRC Health CenterThyroid Disorders (March 2, 2004).

"Thyroid Disorders; Treatment." NWHRC Health CenterThyroid Disorders (March 2, 2004).

ORGANIZATIONS

The Thyroid Foundation of America. 350 Ruth Sleeper Hall RSL 350, Parkman Street, Boston, MA 02114. (800) 8328321. <http://www.clark.net/pub/tfa>.

OTHER

"Endocrine disorder and endocrine surgery." Endocrine Web. <http://www.endocrineweb.com>.

Mai Tran

Teresa G. Odle

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Hyperthyroidism

Hyperthyroidism

Definition

Hyperthyroidism is the overproduction of thyroid hormones by an overactive thyroid.

Description

The term hyperthyroidism covers any disease which results in overabundance of thyroid hormone. Other names for hyperthyroidism, or specific diseases within the category, include Graves' disease, diffuse toxic goiter, Basedow's disease, Parry's disease, and thyrotoxicosis.

Located in the front of the neck, the thyroid gland produces the hormones thyroxin (T4) and triiodothyronine (T3), which regulate the body's metabolic rate by helping to form protein ribonucleic acid (RNA) and increasing oxygen absorption in every cell. In turn, the production of these hormones is controlled by thyroid-stimulating hormone (TSH) that is produced by the pituitary gland. When production of the thyroid hormones increases despite the level of TSH being produced, hyperthyroidism occurs. The excessive amount of thyroid hormones in the blood increases the body's metabolism, creating both mental and physical symptoms.

Demographics

Only about 5 percent of all individuals with hyperthyroidism are younger than 15 years of age. About five times as many girls as boys develop hyperthyroidism. Almost all cases of pediatric hyperthyroidism are the form called Graves' disease. There is a form of hyperthyroidism called neonatal Graves' disease, which occurs in infants born of mothers with Graves' disease. Children with other conditions, such as trisomy 21, Addison's disease, diabetes, systemic lupus erythematosus, rheumatoid arthritis, myasthenia gravis, vitiligo, pernicious anemia, and immune thrombocytopenic purpura are more likely to develop Graves' disease.

Causes and symptoms

Hyperthyroidism is often associated with the body's production of autoantibodies in the blood which causes the thyroid to grow and secrete excess thyroid hormone. This condition, as well as other forms of hyperthyroidism, may be inherited. Regardless of the cause, hyperthyroidism produces the same symptoms, including weight loss with increased appetite, shortness of breath and fatigue, intolerance to heat, heart palpitations, increased frequency of bowel movements, weak muscles, tremors, anxiety , and difficulty sleeping. Adolescent girls may also notice decreased menstrual flow and irregular menstrual cycles.

Patients with Graves' disease often have a goiter (visible enlargement of the thyroid gland), although as many as 10 percent do not. These patients may also have bulging eyes. Thyroid storm, a serious form of hyperthyroidism, may show up as sudden and acute symptoms, some of which mimic typical hyperthyroidism, as well as the addition of fever , substantial weakness, extreme restlessness, confusion, emotional swings or psychosis, or coma. Fortunately, such a fulminant course of Graves' disease is rare in children and adolescents.

Babies with neonatal Graves' disease may suffer from prematurity , airway obstruction, and heart failure. Death occurs in as many as 16 percent of these babies, and other complications from which survivors may suffer include craniosynostosis (early closure of the sutures of the skull, which can result in compression of the growing brain), and developmental delay .

When to call the doctor

Parents should contact a child's pediatrician if the child shows the following symptoms: rapid weight loss, shortness of breath, intolerance to heat, heart palpitations, increased frequency of bowel movements, weak muscles, tremors, anxiety, and difficulty sleeping. An enlarged thyroid gland, seen as a bulge in the neck, should be examined by a doctor.

Diagnosis

Physicians will look for physical signs and symptoms indicated by patient history. On inspection, the physician may note symptoms such as a goiter or eye bulging. Other symptoms or family history may be clues to a diagnosis of hyperthyroidism. An elevated body temperature (basal body temperature) above 98.6°F (37°C) may be an indication of a heightened metabolic rate (basal metabolic rate) and hyperthyroidism. A simple blood test can be performed to determine the amount of thyroid hormone in the patient's blood. The diagnosis is usually straightforward with this combination of clinical history, physical examination, and routine blood hormone tests. Radioimmunoassay (a test to show concentrations of thyroid hormones with the use of a radioisotope mixed with fluid samples) helps confirm the diagnosis. A thyroid scan is a nuclear medicine procedure involving injection of a radioisotope dye, which tags the thyroid and helps produce a clear image of inflammation or involvement of the entire thyroid. Other tests can determine thyroid function and thyroid-stimulating hormone levels. Ultrasonography, computed tomography scans (CT scan), and magnetic resonance imaging (MRI) may provide visual confirmation of a diagnosis or help to determine the extent of involvement.

Treatment

Treatment depends on the specific disease and individual circumstances such as age, severity of disease, and other conditions affecting a patient's health.

Antithyroid drugs

Antithyroid drugs are often administered to help the patient's body cease overproduction of thyroid hormones. This medication may work for young adults, pregnant women, and others. Women who are pregnant should be treated with the lowest dose required to maintain thyroid function in order to minimize the risk of hypothyroidism in the infant.

Radioactive iodine

Radioactive iodine is often prescribed to damage cells that make thyroid hormone. The cells need iodine to make the hormone, so they absorb any iodine found in the body. The patient may take an iodine capsule daily for several weeks, resulting in the eventual shrinkage of the thyroid, reduced hormone production, and a return to normal blood levels. Some patients may receive a single larger oral dose of radioactive iodine to treat the disease more quickly. This should only be done for patients who are not of reproductive age or are not planning to have children, since a large amount can concentrate in the reproductive organs (gonads).

Surgery

Some patients may undergo surgery to treat hyperthyroidism. Most commonly, patients treated with thyroidectomy, in the form of partial or total removal of the thyroid, suffer from large goiter and have suffered relapses, even after repeated attempts to address the disease through drug therapy. Some patients may be candidates for surgery because they were not good candidates for iodine therapy or refused iodine administration. Patients receiving thyroidectomy or iodine therapy must be carefully monitored for years to watch for signs of hypothyroidism (insufficient production of thyroid hormones), which can occur as a complication of thyroid production suppression.

KEY TERMS

Goiter Chronic enlargement of the thyroid gland.

Gonads Organs that produce gametes (eggs or sperm), i.e. the ovaries and testes.

Palpitations Rapid and forceful heartbeat.

Radioisotope One of two or more atoms with the same number of protons but a different number of neutrons with a nuclear composition. In nuclear scanning, radioactive isotopes are used as a diagnostic agent.

Thyroidectomy Surgical removal of all or part of the thyroid gland.

Prognosis

Hyperthyroidism is generally treatable and carries a good prognosis. Most patients lead normal lives with proper treatment. Thyroid storm, however, can be life-threatening and can lead to heart, liver, or kidney failure. Luckily, this form of fulminant hyperthyroidism is rare in children and adolescents.

Prevention

As of 2004 there are no known prevention methods for hyperthyroidism; its causes are either inherited or not completely understood. The best prevention tactic is knowledge of family history and close attention to symptoms and signs of the disease. Careful attention to prescribed therapy can prevent complications of the disease.

Parental concerns

Parents should be aware that hyperthyroidism is very rare in young children. However, once diagnosed, the condition needs short- and long-term treatment, with regular follow-up visits to the doctor.

Resources

BOOKS

"Hyperthyroidism." In Nelson Textbook of Pediatrics. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2004.

PERIODICALS

Hanna, C. E. "Adolescent Thyroid Disorders." Adolescent Medicine 13 (February 2002): 1335.

ORGANIZATIONS

Thyroid Foundation of America. 350 Ruth Sleeper Hall, RSL 350, Parkman St., Boston, MA 02114. Web site: <www.clark.net/pub/tfa>.

Teresa Norris, RN Rosalyn Carson-DeWitt, MD

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"Hyperthyroidism." Gale Encyclopedia of Children's Health: Infancy through Adolescence. . Retrieved October 16, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/hyperthyroidism-0

Hyperthyroidism

Hyperthyroidism

Definition

Hyperthyroidism is the overproduction of thyroid hormones by an overactive thyroid.

Description

Located in the front of the neck, the thyroid gland produces the hormones thyroxine (T4) and triiodothyronine (T3) that regulate the body's metabolic rate by helping to form protein ribonucleic acid (RNA) and increasing oxygen absorption in every cell. In turn, the production of these hormones are controlled by thyroid-stimulating hormone (TSH) that is produced by the pituitary gland. When production of the thyroid hormones increases despite the level of TSH being produced, hyperthyroidism occurs. The excessive amount of thyroid hormones in the blood increases the body's metabolism, creating both mental and physical symptoms.

The term hyperthyroidism covers any disease which results in overabundance of thyroid hormone. Other names for hyperthyroidism, or specific diseases within the category, include Graves' disease, diffuse toxic goiter, Basedow's disease, Parry's disease, and thyrotoxicosis. The disease is 10 times more common in women than in men, and the annual incidence of hyperthyroidism in the United States is about one per 1,000 women. Although it occurs at all ages, hyperthyroidism is most likely to occur after the age of 15. There is a form of hyperthyroidism called Neonatal Grave's disease, which occurs in infants born of mothers with Graves' disease. Occult hyperthyroidism may occur in patients over 65 and is characterized by a distinct lack of typical symptoms. Diffuse toxic goiter occurs in as many as 80% of patients with hyperthyroidism.

Causes and symptoms

Hyperthyroidism is often associated with the body's production of autoantibodies in the blood which cause the thyroid to grow and secrete excess thyroid hormone. This condition, as well as other forms of hyperthyroidism, may be inherited. Regardless of the cause, hyperthyroidism produces the same symptoms, including weight loss with increased appetite, shortness of breath and fatigue, intolerance to heat, heart palpitations, increased frequency of bowel movements, weak muscles, tremors, anxiety, and difficulty sleeping. Women may also notice decreased menstrual flow and irregular menstrual cycles.

Patients with Graves' disease often have a goiter (visible enlargement of the thyroid gland), although as many as 10% do not. These patients may also have bulging eyes. Thyroid storm, a serious form of hyperthyroidism, may show up as sudden and acute symptoms, some of which mimic typical hyperthyroidism, as well as the addition of fever, substantial weakness, extreme restlessness, confusion, emotional swings or psychosis, and perhaps even coma.

Diagnosis

Physicians will look for physical signs and symptoms indicated by patient history. On inspection, the physician may note symptoms such as a goiter or eye bulging. Other symptoms or family history may be clues to a diagnosis of hyperthyroidism. An elevated body temperature (basal body temperature) above 98.6 °F (37 °C) may be an indication of a heightened metabolic rate (basal metabolic rate) and hyperthyroidism. A simple blood test can be performed to determine the amount of thyroid hormone in the patient's blood. The diagnosis is usually straightforward with this combination of clinical history, physical examination, and routine blood hormone tests. Radioimmunoassay, or a test to show concentrations of thyroid hormones with the use of a radioisotope mixed with fluid samples, helps confirm the diagnosis. A thyroid scan is a nuclear medicine procedure involving injection of a radioisotope dye which will tag the thyroid and help produce a clear image of inflammation or involvement of the entire thyroid. Other tests can determine thyroid function and thyroid-stimulating hormone levels. Ultrasonography, computed tomography scans (CT scan), and magnetic resonance imaging (MRI) may provide visual confirmation of a diagnosis or help to determine the extent of involvement.

Treatment

Treatment will depend on the specific disease and individual circumstances such as age, severity of disease, and other conditions affecting a patient's health.

Antithyroid drugs

Antithyroid drugs are often administered to help the patient's body cease overproduction of thyroid hormones. This medication may work for young adults, pregnant women, and others. Women who are pregnant should be treated with the lowest dose required to maintain thyroid function in order to minimize the risk of hypothyroidism in the infant.

Radioactive iodine

Radioactive iodine is often prescribed to damage cells that make thyroid hormone. The cells need iodine to make the hormone, so they will absorb any iodine found in the body. The patient may take an iodine capsule daily for several weeks, resulting in the eventual shrinkage of the thyroid in size, reduced hormone production and a return to normal blood levels. Some patients may receive a single larger oral dose of radioactive iodine to treat the disease more quickly. This should only be done for patients who are not of reproductive age or are not planning to have children, since a large amount can concentrate in the reproductive organs (gonads).

Surgery

Some patients may undergo surgery to treat hyperthyroidism. Most commonly, patients treated with thyroidectomy, in the form of partial or total removal of the thyroid, suffer from large goiter and have suffered relapses, even after repeated attempts to address the disease through drug therapy. Some patients may be candidates for surgery because they were not good candidates for iodine therapy, or refused iodine administration. Patients receiving thyroidectomy or iodine therapy must be carefully monitored for years to watch for signs of hypothyroidism, or insufficient production of thyroid hormones, which can occur as a complication of thyroid production suppression.

Alternative treatment

Consumption of foods such as broccoli, brussel sprouts, cabbage, cauliflower, kale, rutabagas, spinach, turnips, peaches, and pears can help naturally suppress thyroid hormone production. Caffeinated drinks and dairy products should be avoided. Under the supervision of a trained physician, high dosages of certain vitamin/mineral combinations can help alleviate hyperthyroidism.

Prognosis

Hyperthyroidism is generally treatable and carries a good prognosis. Most patients lead normal lives with proper treatment. Thyroid storm, however, can be life-threatening and can lead to heart, liver, or kidney failure.

Prevention

There are no known prevention methods for hyperthyroidism, since its causes are either inherited or not completely understood. The best prevention tactic is knowledge of family history and close attention to symptoms and signs of the disease. Careful attention to prescribed therapy can prevent complications of the disease.

Resources

ORGANIZATIONS

Thyroid Foundation of America. 350 Ruth Sleeper Hall-RSL 350, Parkman St., Boston, MA. 02114. (800) 832-8321. http://www.clark.net/pub/tfa.

OTHER

"Endocrine Disorder and Endocrine Surgery." Endocrine Web Page. http://www.endocrineweb.com.

KEY TERMS

Goiter Chronic enlargement of the thyroid gland.

Gonads Organs that produce sex cellsthe ovaries and testes.

Palpitations Rapid and forceful heartbeat.

Radioisotope A chemical tagged with radioactive compounds that is injected during a nuclear medicine procedure to highlight organ or tissue.

Thyroidectomy Removal of the thyroid gland.

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hyperthyroidism

hyperthyroidism The classic picture of excessive thyroid activity is that of a patient with Graves' disease — a form of thyrotoxicosis. Robert Graves was a renowned Dublin physician, whose bicentenary was celebrated in 1996. In addition to promoting a radical innovation in medical education — ward rounds with bedside teaching — he wrote in 1835 the first clear description of this disease. In a short paper titled ‘Palpitation of the heart with enlargement of the thyroid gland’, he recognized the defining significance of a ‘triad’ of symptoms: goitre, protruding eyes, and palpitations.

In the UK about 2% of women will suffer from thyroid overactivity (hyperthyroidism). It is ten times less likely among men. The hyperthyroidism of at least 50% of the patients is due to Graves' disease — now known to be an autoimmune condition.

Normally, thyroid activity is subject to positive regulation by thyroid stimulating hormone (TSH), which is secreted from the pituitary and stimulates thyroid growth and function. Very rarely, thyrotoxicosis is caused by excessive production of TSH. Hyperthyroidism of non-autoimmune origin is usually due to either a toxic nodular goitre (‘Plummer's disease’, after a physician at the Mayo Clinic in the 1920s) or a toxic adenoma — a benign tumour in which the cells retain the follicular arrangement characteristic of the thyroid gland. In complete contrast, the overactivity encountered in Graves' disease is due to the aberrant production of autoantibodies, known as thyroid stimulating antibodies. These mimic TSH and persistently stimulate the thyroid follicular cells. These antibodies are unique in having a stimulating as opposed to a blocking action. They were first described in a classic series of studies conducted in the 1950–60s by Adams and Purves in the University of Otago.

Thyroid overactivity results in the secretion of excessive amounts of thyroid hormones into the bloodstream. As a consequence, the clinical symptoms are the exaggerated effects of thyroid hormones on peripheral tissues. The basal metabolic rate increases and the effects of some other hormones — notably adrenaline — are potentiated. The symptoms include persistent weight loss despite a healthy appetite, sweating, hand tremor, and often a goitre. The patient is agitated, fatigues easily, and is intolerant of heat. Adrenaline potentiation is most seriously manifested by atrial fibrillation (a fast, irregular heartbeat). Some symptoms are additionally indicative of an autoimmune origin of the hyperthyroidism — Graves' disease. These include eye signs, which range from protruding eyes (exophthalmos) to — in very rare cases — optic nerve compression with loss of vision. There can also be a characteristic thickening of the skin over the lower legs and on the tops of the feet or big toes. If there is a goitre, it is a diffuse enlargement and an isotope scan shows that the entire gland is uniformly overactive.

A hyperthyroid patient may be rendered euthyroid (hormone levels within normal limits) with antithyroid drugs, for example carbimazole, which inhibit the biosynthesis of thyroid hormones. After treatment for 12–18 months, spontaneous remissions occur in about half the patients with Graves' disease, so that if the antithyroid drugs are withdrawn the symptoms do not recur. This is typical of the ‘waxing and waning’ of some autoimmune conditions, and remissions were described without specific treatment in the early nineteenth-century reports. By contrast, spontaneous remission will not occur in patients suffering from hyperthyroidism of non-autoimmune origin. If remission is not achieved, long-term treatment usually requires partial or total elimination of the thyroid. This is achieved either by the use of radioiodine or by surgical removal (thyroidectomy).

N. J. Marshall


See also goitre; hormones; hypothyroidism; thyroid.

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Hyperthyroidism

HYPERTHYROIDISM

Hyperthyroidism is the condition that reflects excessive concentrations of thyroid hormones, due to any cause. The resulting hypermetabolic state causes increased heat production and accelerates many of the bodies' processes. Common causes are Graves' disease, hyperfunctioning benign thyroid tumors, and thyroid inflammations. Untreated, patients may have severe and progressive disability that includes weight loss, muscle weakness, loss of mineral from their bones, and increased risk for dangerous heart arrhythmias. Available treatments include one of several "antithyroid drugs," such as methimazole and propylthiouracil, that prevent overproduction of thyroid hormones, and radioctive iodine (I-131) treatment or surgery, which either destroy or remove the thyroid tissue.

Martin I. Surks

(see also: Goiter; Hypothyroidism; Thyroid Disorders; Thyroid Function Tests )

Bibliography

Wartofsky, L. (1999). "Hyperthyroidism." In Atlas of Clinical Endocrinology, Vol. 1: Thyroid Diseases, ed.M. I. Surks. Philadelphia, PA: Current Medicine.

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hyperthyroidism

hy·per·thy·roid·ism / ˌhīpərˈ[unvoicedth]īroiˌdizəm/ • n. Med. overactivity of the thyroid gland, resulting in a rapid heartbeat and an increased rate of metabolism. Also called thyrotoxicosis. DERIVATIVES: hy·per·thy·roid adj. hy·per·thy·roid·ic / -[unvoicedth]īˈroidik/ adj.

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hyperthyroidism

hyperthyroidism (hy-per-th'y-roid-izm) n. overactivity of the thyroid gland, either due to a tumour, overgrowth of the gland, or Graves' disease. apathetic h. a condition seen in patients with thyrotoxicosis, characterized by slow atrial fibrillation and depressive illness. See thyrotoxicosis.

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hyperthyroidism

hyperthyroidism Excessive production of thyroid hormone, with enlargement of the thyroid gland. Symptoms include protrusion of the eyeballs, rapid heart rate, high blood pressure, accelerated metabolism, and weight loss. See also hypothyroidism

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"hyperthyroidism." World Encyclopedia. . Encyclopedia.com. (October 16, 2017). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/hyperthyroidism

"hyperthyroidism." World Encyclopedia. . Retrieved October 16, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/hyperthyroidism

hyperthyroidism

hyperthyroidism Overactivity of the thyroid gland. This condition causes an increase in basal metabolic rate, with such symptoms as rapid pulse and weight loss. It is sometimes associated with a goitre. Compare hypothyroidism.

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"hyperthyroidism." A Dictionary of Biology. . Encyclopedia.com. 16 Oct. 2017 <http://www.encyclopedia.com>.

"hyperthyroidism." A Dictionary of Biology. . Encyclopedia.com. (October 16, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/hyperthyroidism

"hyperthyroidism." A Dictionary of Biology. . Retrieved October 16, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/hyperthyroidism

hyperthyroidism

hyperthyroidism: see thyroid gland.

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"hyperthyroidism." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 16 Oct. 2017 <http://www.encyclopedia.com>.

"hyperthyroidism." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (October 16, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/hyperthyroidism

"hyperthyroidism." The Columbia Encyclopedia, 6th ed.. . Retrieved October 16, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/hyperthyroidism

hyperthyroidism

hyperthyroidism See thyrotoxicosis.

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"hyperthyroidism." A Dictionary of Food and Nutrition. . Encyclopedia.com. 16 Oct. 2017 <http://www.encyclopedia.com>.

"hyperthyroidism." A Dictionary of Food and Nutrition. . Encyclopedia.com. (October 16, 2017). http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/hyperthyroidism

"hyperthyroidism." A Dictionary of Food and Nutrition. . Retrieved October 16, 2017 from Encyclopedia.com: http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/hyperthyroidism