Williams, in comprehensive handbook of iodine, 2009. Effect of iodide on nicotinamide adenine dinucleotide. Prevention and treatment of iodineinduced thyrotoxicosis. Abstractthe inhibitory effect of supraphysiological iodide concentrations on thyroid hormone synthesis wolffchaikoff effect and on thyrocyte proliferation is largely known as iodine autoregulation. Its iodine content was initially low, but rose to a normal value of 0. Unlike thyrotoxicosis, hypothyroidism is related to a persistent wolffchaikoff effect and often has a vague presentation. The study, that was later referred to as the wolffchaikoff wc effect says that iodine intake of. Jan wolff and israel lyon chaikoff at the university of california berkeley, is a presumed reduction in thyroid hormone levels caused by ingestion of a large amount of iodine.
To prevent the development of hypothyroidism after exposure to excessive iodine, an escape from the acute wolffchaikoff effect should occur. The wolff chaikoff effect has been used as a treatment principle against hyperthyroidism especially thyroid storm by infusion of a large amount of iodine to suppress the thyroid gland. At the other end of the spectrum, iodineinduced thyrotoxicosis, known as the jodbasedow phenomenon, can also occur, especially in. Without preconceived ideas, it is easily explained inorganic, nonradioactive iodine is safe. Hosam al tamimi at jordan university of science and technology.
Icri mumbai case 1 a 15 yearold unconscious boy is admitted to the emergency room. However, iodine does not occur in the free state in nature. Transarterial chemoembolization tace is the standard of care for patients with an intermediate or advanced stage of hepatocellular carcinoma hcc and compensated liver cirrhosis. Overall, hyperthyroidism is basedoe by an increase in resting heart rate, blood volume, stroke volume, myocardial contractility, and ejection fraction. Iodine intake has a negative effect on the expression of nis and high doses of iodide block thyroid hormone synthesis via inhibition of organification wolffchaikoff effect 3437. We report a case of erythema nodosum treated with potassium iodide with the development of profound hypothyroidism secondary to exogenous intake of iodide. Thus tsh diminished the blocking effect ofa given intrathyroidal iodide concentration. In most individuals, very high iodine intakes transiently and paradoxically inhibit thyroid hormone production, termed the acute wolffchaikoff effect wolff and chaikoff 1948. Wolffchaikoff effect an overview sciencedirect topics. Pdf the wolffchaikoff effect ameliorates heat stress in.
Although other adrenergic blockers can be used, high doses of propranolol decrease t4 t3 conversion, and the doses can be easily adjusted. According to the authors a twostep wolffchaikoff effect has been induced. He also had multiple follicular and papillary thyroid carcinomas with a metastatic lesion in the lumbar vertebrae. The developing thyroid is inordinately sensitive to the inhibitory effect of excess iodide the wolffchaikoff effect wolff and chaikoff, 1948 with the subsequent development of goiter andor hypothyroidism roti and vagenakis, 2000. He and his colleagues were pioneers in the use of radioactive iodine to investigate thyroid function.
Effects of amiodarone on thyroid function annals of. Under high doses of iodide the glands reaccumulated thyroglobulin. The adaptation to the initial inhibitory effect the escape from the wolffchaikoff effect occurs as a result of. Normally, this is only temporary, and after a short disruption there is an escape and thyroid function returns to normal after a few days, even if high iodine. November december pages finally, medications such as amiodarone may induce hypothyroidism mediated by efecti wolff. The physician on duty is participating in a clinical trial and after an initial assessment the considers the patient suitable for the study. Recommended articles citing articles 0 references 1. However, hyperthyroidism has not been reported as one of its complications.
Thyroid function tests revealed a thyroid stimulating hormone tsh level of 0. Mechanism of action wolff chaikoff effect inhibition of. Excess iodide transiently inhibits thyroid iodide organification,a phenomenon known as the wolffchaikoff effect. A perspective view of sodium iodide symporter research and. She has not medical problems, but some of her family members have similar symptoms and require medication. Errors in modern thyroid endocrinology jeffrey dach md. The adaptation to the initial inhibitory effect the escape from the wolffchaikoff effect occurs as a result of decreased iodide transport. Acute myocardial infarction as the first presentation of. However, this inhibitory effect wolffchaikoff effect lasts only 1014 days, followed by the socalled escape phenomenon 6. The current study aimed to examine the wc on thermophysiology of rats exposed to. A rapid thyrosuppressive mechanism wolff chaikoff phenomenon. Thyroperoxidase requires h 2 o 2 to catalyze the biosynthesis of thyroxine residues on thyroglobulin. Iodineinduced hypothyroidism mary ann liebert, inc. He is believed to be an immunemediated disorder rather than representing the direct effect of an altered thyroid state on the central nervous system.
Failure to escape the wolffchaikoff effect can result in iodineinduced hypothyroidism in susceptible individuals. Medical options include therapy with thionamides, perchlorate, and prednisone. In 1948, wolff and chaikoff reported that organic binding of iodide in the thyroid was decreased when plasma iodide levels were elevated acute wolffchaikoff effect, and that adaptation or escape from the acute effect occurred in approximately 2 days, in the presence of. The acute wolffchaikoff effect, a transient reduction in thyroid hormone synthesis after exposure to high amounts of iodine, was first described by drs jan wolff and israel lyon chaikoff in 1948.
Hypothyroidism is a common condition of thyroid hormone deficiency, which is readily diagnosed and managed but potentially fatal in severe cases if untreated. Jan wolff and israel lyon chaikoff at the university of california, is a presumed reduction in thyroid hormone levels caused by ingestion of a. A systems biology approach to propose a new mechanism of. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a pdf plugin installed and enabled in your browser.
Findarticles is a cbs interactive portal that lets you find articles about any topic, by searching in our network of news and technology sites, including cbs news, cnet, and others. The findings of recent studies support the idea that blockade of iodine organification during the wolffchaikoff effect is mainly attributable to the inhibition of nadph oxidase activity leading to decreased generation of. Pdf the wolffchaikoff effect ameliorates heat stress in rats. Escape from the acute wolffchaikoff effect is associated. The acute wolffchaikoff effect lasts for few a days and then, through the socalled escape phenomenon, the. They next demonstrated that this inhibitory effect of excess iodide was transient, lasting from 2650 h. Selenium ameliorates toxic effect of iodine in nod mice autoimmune prone antibody levels gradually decrease. Marine drugs free download as powerpoint presentation. Hypothyroidism wolffchaikoff effect occurs frequently. However, the molecular mechanisms by which iodide modulates thyroid function remain unclear. As with all other halogens, when freed from its compounds iodine forms diatomic molecules i2. Download pdf check for updates get permissions abstractexcerpt.
Thyroid hormones and moderate exposure to perchlorate. Rapid regulation of thyroid sodiumiodide symporter. Studies since the 1970s have highlighted that direct iodide. Atsdr principles of pediatric environmental health. Israel lyon chaikoff 2 july 1902, london, uk 25 january 1966, berkeley, california was a canadianamerican physiologist and biochemist, known for the wolffchaikoff effect. The wolff chaikoff effect is an effective means of rejecting a large quantity of imbibed iodide, and therefore preventing the thyroid from synthesizing large quantities of thyroid hormone. Jan wolff and israel lyon chaikoff at the university of california berkeley, is a presumed reduction in thyroid. On examination, she is noted to have exophthalmos, an enlarged nontender goiter, hyperreflexia, and a tremor when her arms are outstretched. Thyroid cancer tc is the most common endocrine malignancy and in most countries, incidence rates are increasing. The wolff chaikoff effect is an effective means of rejecting a large quantity of imbibed iodide, and therefore preventing the. Risk of iodineinduced thyrotoxicosis after coronary angiography. In 1948, wolff and chaikoff reported that injection of iodine in rats almost completely inhibited organification thyroglobulin iodination in the thyroid gland. Iodide inhibits the generation of h 2 o 2, and consequently the synthesis of thyroid hormones wolffchaikoff effect. The wolffchaikoff effect was also overcome by the presence of a hydrogen peroxidegenerating system, such as glucoseglucoseoxidase or tyramine.
The rarity of iodide goiter in the face of the extensive exposure of a great many patients to iodide has not been satisfactorily explained. Wolff and chaikoff reported in 1948 that organic binding of iodide which later was shown to be mediated by tpo in the rat thyroid in vivo was blocked when iodide plasma levels reached a critical high threshold, a phenomenon known as the acute wolffchaikoff effect. Escape from the acute wolffchaikoff effect is associated with a. In susceptible individuals amiodarone may precipitate or exacerbate preexisting organspecific autoimmunity14. It is known that the prolonged use of iodides can lead to hypothyroidism, termed the wolffchaikoff effect. In 1948, wolff and chaikoff reported that organic binding of iodide in the thyroid was. Chemically, iodine is the least reactive of the halogens, and the most electropositive halogen after astatine. Hyperthyroidism secondary to hysterosalpingography. Effect of excess iodine intake on thyroid on human health. Iodine and its compounds are primarily used in medicine, photography, and dyes. A second effect involves inhibition of iodine organification in the thyroid gland, thereby diminishing thyroid hormone biosynthesis, a phenomenon called the wolffchaikoff effect. Acidsuppressive drugs, such as proton pump inhibitors ppis or histamine2 receptor antagonists h2asare recommended algorithm for the treatment of convulsion in patients wartofsmy thyroid storm. Rescue preoperative treatment with lugols solution in.
Download acrobat pdf file 171kb supplementary appendix. This acute wolffchaikoff effect results in an increase in intrathyroid iodine concentration within 2448 h and a decrease in thyroid hormone synthesis in normal rats. Pdf effect of excess iodine intake on thyroid on human. We read with interest the article by johnson and rapini in a recent issue of the archives 1 on transient primary hypothyroidism induced by iodine application in an elderly woman.
Zimmermann, valeria galetti, iodine intake as a risk factor for thyroid cancer. If your provider is having you use lugols solution or ioderal, or cant tell you exactly how many milligrams you are taking daily, i recommend that you think twice. We report the case of a 33yearold euthyroid woman who presented to our hospital with palpitation, hand tremor, fatigue, and excessive sweating after hsg. Wolffchaikoff effect and cause partial inhibition of tg proteolysis. Iodinated contrast medium exposure during computed.
Ki essentially saturates the iodide transport mechanism of the thyroid by inhibiting the intrathyroid organification of iodide acute wolffchaikoff effect, by dilution and by promoting excretion and thus, reducing the amount of committed dose to the thyroid gland, its. Graves disease a 41yearold woman presents to her primary care physician with weight and hair loss, diarrhea, nervousness, and eye pressure. After a total thyroidectomy, he became slightly hypothyroid, and the lumbar lesion began to incorporate 1i by scintigraphy. Wolffchaikoff effect the delay allows the antithyroid drug to prevent the excess iodine from being incorporated into new hormone. High doses of iodine can paradoxically suppress thyroid function wolffchaikoff effect. Large doses of stable iodine acutely inhibit thyroid hormone synthesis wolffchaikoff effect and thyroid hormone release. In 1948, wolff and chaikoff reported that injection of iodine in rats almost. Although differences in population iodine intake are a determinant of benign thyroid disorders, the role of iodine intake in tc remains uncertain. Scribd is the worlds largest social reading and publishing site. This csem focuses on principles of pediatric environmental health and serves as a companion piece to the pediatric exposure history csem. Direct toxic effect of the drug on thyroidal cells12. Patients with graves hyperthyroidism are more sensitive to the inhibitory effect of pharmacologic doses of. Thyroidectomy is effective and is the only measure that consistently allows continued use of amiodarone.
This case study also serves to explicate further some of the background principles that form the bases for the pediatric environmental medicine practices found in the pediatric exposure history csem. The h 2 o 2 generator is a calciumdependent nicotinamide adenine dinucleotide phosphate nadph oxidase involving the flavoprotein duox2. Abstract exposure to excessive amounts of iodine blocks the activity of the enzyme thyroid peroxidase tpoa phenomenon known as wolf chaikoff effect. Jan wolff and israel lyon chaikoff at the university of california, is a presumed reduction in thyroid hormone levels. In a study on screening for hypothyroidism in hamburg, west germany, in a series of 91509 neonates, the determination of thyrotropin levels was done by the radioimmunologic thyrotropin neonatal dry.1336 1152 526 902 927 1116 346 726 55 102 307 1275 922 440 1531 459 1349 1093 168 44 423 1223 1158 513 1476 111 1537 255 341 319 1273 623 1246 994 320 408 415 947 303 1064 1164 932 439 970 1221 477 453