Information for behavioral health providers in primary care. This is roughly 50fold higher than the daily recommended iodine intake for adults. Pdf 150 microg iodine are daily required for thyroid hormone synthesis. Iodideinduced hyperthyroidism within four hours of iodide load. A typical iodinated contrast study confers approximately 500. Pdf to summarize the mechanisms of iodineinduced hypothyroidism and. Although amiodarone is regarded as a highly effective antiarrhythmic agent, its use may lead to alterations in thyroid gland function andor thyroid hormone metabolism, partly because of its rich iodine content. Signs and symptoms vary between people and may include irritability, muscle weakness, sleeping problems. Here is a brief outline about certain foods for hyperthyroidism that should be. Primary care physicians 2018 thyroid patient care resolutions. Type 2 amiodaroneinduced hyperthyroidism resembles a destructive thyroiditis, where increased amounts of thyroid hormone are released iv contrast agents for ct scans. Dietary sources high in iodine, such as kelp, if taken in extreme abundance, can introduce too much iodine into the body and create an iodine induced hyperthyroidism.
Summary iodineinduced thyroid dysfunction may be subclinical or overt. Since the initial description by coindet in 1821 18 and the subsequent definition by breuer and kocher in 1904, iodineinduced hyperthyroidism has been reported in pa. See iodineinduced thyroid dysfunction and thyroid hormone synthesis and physiology. Hyperthyroidism is an excessive concentration of thyroid hormones. Cases of acute iodine poisoning are rare and are usually caused by doses of many grams. Iodineinduced hyperthyroidisman old clinical entity that is still. Type ii amiodarone induced thyrotoxicosis is a destructive thyroiditis caused by a direct toxic effect of amiodarone on thyrocytes. Nonbioavailable iodine may be liberated to free iodide, particularly with increased halftimes in the body i. Iodide induced hyperthyroidism iodide induced hyperthyroidism is not a single etiologic entity. Finally, based on studies of iodineinduced thyroid dysfunction associated with amiodarone use, 10 hyperthyroidism following administration of iodinated contrastmedium hyperthyroidism is likely to be more prevalent in iodinedeficient regions, and hypothyroidism in iodinesufficient areas. Amiodaroneinduced toxic nodular goiter, a form of iodineinduced thyrotoxicosis, was described in europe where large nodular goiters are more prevalent than in the united states.
Hypothyroidism can easily be treated with a thyroid hormone supplement taken once a day see hypothyroidism brochure. The iodine deficiency disorders thyroid disease manager. This phenomenon is thus iodineinduced hyperthyroidism, typically presenting in a. Iodine is an essential element for thyroid hormone synthesis. Iodineinduced hyperthyroidism is usually seen in patients who already have an underlying abnormal thyroid gland. Iodideinduced hyperthyroidism iodideinduced hyperthyroidism is not a single etiologic entity.
The main causes are related to autoimmune and neoplastic pathology. Most cases of iodine induced hyperthyroidism are selflimited and resolve when. Type 1 ait ait 1 is a form of iodineinduced hyperthyroidism. The use of iodine for goiter still was not used as it was seen as toxic and or irrational. Recognition of the association between iodine excess and iodineinduced hypothyroidism or hyperthyroidism is important in the differential diagnosis of patients who present without a known cause of thyroid dysfunction. This exposure leads to excess thyroid hormone synthesis and release, similar to iodine induced hyperthyroidism in patients receiving excess iodine from other sources. Up to date information on idd can be obtained by visiting the website of the iodine global network. Balance is important in all aspects of life, especially nutrition. The condition resolved after povidone iodine was replaced by a iodine free antiseptic solution.
However, it might be caused due to a longterm topical exposure iodine solution dressing or by intravenous administration of iodinecontaining substances. Topical iodine and hyperthyroidism annals of internal. Iodine deficiency early in life can make people more vulnerable to iodineinduced hyperthyroidism later on. Iodine deficiency disorders and the therapeutic use of iodine in patients with hyperthyroidism are discussed separately. Iodine in the treatment of hyperthyroidism uptodate. Hyperthyroidism is an excessive concentration of thyroid hormones in tissues causing a characteristic clinical state. This can cause big problems in developing countries, where a lot of people have preexisting iodine deficiencies and governments or ngos start an iodine supplementation scheme. The autoimmune disorder graves disease comprises 85% of all cases of hyperthyroidism.
In the united states, the overall prevalence of hyperthyroidism is 1. Iodine induced thyrotoxicosis following povidineiodine dressings. Pdf iodine excess and hyperthyroidism researchgate. Contrast induced hyperthyroidism due to iodine excess. Her tsh remains low but the free thyroxine and free triiodothyronine have improved. Amiodarone cordarone is a commonly prescribed medication for the management of both atrial and ventricular arrhythmias. Iodineinduced hyperthyroidism can also result from high iodine intakes, usually when iodine is administered to treat iodine deficiency. Unforunately, each 200 mg tablet of amiodarone contains 74. Prevention of iodineinduced thyrotoxicosis in highrisk patients is important, as treatment with thyrostatic drugs is hindered by the high iodide concentrations and complications are more frequent than in other forms of thyrotoxicosis. Iodineinduced hyperthyroidism can last from one month to 18 months and is treated by discontinuing iodine and, if indicated, administering a. The effects of iodine toxicity may persist for months.
In cases of established hyperthyroidism, administration of icm is contraindicated. Iodine is an element that is needed for the production of thyroid hormone. Radioactive iodine has been used to treat patients for hyperthyroidism for over 60 years and has been shown. The jodbasedow effect also jodbasedow syndrome and jodbasedow phenomenon is hyperthyroidism following administration of iodine or iodide, either as a dietary supplement or as iodinated contrast for medical imaging.
Most cases of iodineinduced hyperthyroidism are selflimited and resolve when. Guidelines by the us institute of medicine recommend a daily iodine intake of 150. Hyperthyroidism induced by topical iodine endocrinologia y. This exposure leads to excess thyroid hormone synthesis and release, similar to iodineinduced hyperthyroidism in patients receiving excess iodine from other sources. In this phase, serum total t4 tt4, free t4 ft4, and reverse t3 rt3 levels. A better understanding of this geographic variation. The disease is much more common in women than in men 8. Despite antithyroid drug therapy, some patients demonstrated refractory hyperthyroidism. Both iodine deficiency and excess can cause thyroid dysfunction. No free triiodothyronine ft3 and free thyroxine ft4 levels were ordered at. Iodine induced hyperthyroidism is frequently observed in patients affected by euthyroid iodine deficient goiter when suddenly exposed. Iodineinduced thyroid dysfunction may be subclinical or overt. Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormones by the thyroid gland.
Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause and therefore includes hyperthyroidism. The body does not make iodine, so it is an essential part of your diet. We wish to report what may be the first described case of iodineinduced hyperthyroidism resulting from cutaneous absorption of a topical preparation. The prevalence of iodineinduced hyperthyroidism is lower in iodinesufficient geographic areas such as north america, 22. Hence, a proper hyperthyroidism diet plays a key role in reversing the condition. Scintigraphic manifestations of thyrotoxicosis radiographics. The iodinecontaining drug most commonly associated with iodineinduced hyperthyroidism is amiodarone, an antiarrhythmic cardiac drug used for refractory arrhythmias.
While iodine deficiency plagues much of the world, consuming too much iodine can also be a concern. Tu sum up, a case of subclinical hyperthyroidism induced by excess topical iodine is reported in a patient with no prior thyroid disease. This is the most acute effect of iodine on thyroid status, occurring within hours of the start of therapy. Hyperthyroidism has been described as elevated serum free t3 andor free t4 levels with decreased thyrotropin tsh concentrations.
Iodineinduced hyperthyroidisman old clinical entity that. Lack of iodine can lead to a disorder of the thyroid gland called as hypothyroidism. Hyperthyroidism thyrotoxicosis is a group of disorders characterized by increased free t 4 andor t 3. The radioactive iodine assessment should help to distinguish graves hyperthyroidism from iodineinduced hyperthyroidism. Iodideinduced hyperthyroidism within four hours of.
Iodine induced thyrotoxicosis following povidineiodine. Studies have also shown that excessive iodine intakes cause thyroiditis and thyroid papillary cancer 2,59. If your thyroid is too active, it makes more thyroid hormones than your body needs. In hyperthyroid patients, iodine acutely inhibits hormonal secretion, but the responsible mechanisms are uncertain. Since the initial description by coindet in 1821 18 and the subsequent definition by breuer and kocher in 1904, iodine induced hyperthyroidism has been reported in pa. A young woman, brenda, was found to have essentially no urinary iodine excretion, indicating iodine deficiency. Hyperthyroidism and iodine deficiency thyroid center. How should iodineinduced and amiodaroneinduced thyrotoxicosis be managed. A proper diet aims at easing the symptoms of hyperthyroidism and it basically comprises of reduced iodine intake as it helps to reverse iodineinduced hyperthyroidism in many cases.
Hyperthyroidism is more common in women, people with other thyroid problems, and those over 60 years old. The mechanism for amiodaroneinduced hyperthyroidism and. Iodineinduced hyperthyroidism definition of iodine. Excess iodine in the contrast material used for ct scans may cause an increased production of thyroid hormone. Prevention and treatment of iodineinduced thyrotoxicosis. Jacques department of intensive care, the st george hospital, kogarah, new south wales abstract a 40yearold woman was admitted to the intensive care unit after a radical resection of a recurrent abdominal malignancy.
Specifically, patients treated with antithyroid drugs for graves disease are prone to develop iodineinduced hyperthyroidism. The clinical signs of the disease are the classical signs of any form of hyperthyroidism, but the treatment. Type ii amiodaroneinduced thyrotoxicosis is a destructive thyroiditis caused. Certain medications, such as amiodarone cordarone, which is used in the treatment of heart problems, contain a large amount of iodine and may be associated with thyroid function.
Iodine induced hyperthyroidism the jodbasedow phenomenon was first described in the early 1800s, when thyrotoxicosis was observed to be more common among patients with endemic goiter treated with iodine supplementation than in individuals without goiter. The thyroid gland has the capacity and holds the machinery to handle the iodine efficiently when the availability of iodine becomes scarce, as well as when iodine is available in excessive quantities. Iodine is vital for the development of our brain cells and for the regulation and production of the thyroid hormones. Hyperthyroidism overactive thyroid symptoms, treatment. Iodineinduced hyperthyroidism increased susceptibility of the thyroid gland to nuclear radiation. These include how fast you burn calories and how fast your heart beats. In 1972, however, iodine thyrotoxicosis was first reported from an iodinesufficient area 3. Most cases of iodineinduced hyperthyroidism are selflimited and resolve when exposure ceases.
Pdf iodineinduced thyroid dysfunction researchgate. Increased prevalence of hyperthyroidism as an early and. Patients treated with amiodarone may manifest altered thyroid hormone profile without thyroid dysfunction, or they may present with clinically significant amiodaroneinduced. Hyperthyroidism is an excessive concentration of thyroid hormones in tissues caused by increased synthesis of thyroid hormones, exces sive release of preformed thyroid hormones, or an endogenous or. Amiodarone induced hyperthyroidism was considered but was thought to be unlikely as the drug was stopped a year ago.
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