Goitre

Iodine occurs to a minute extent (less than 0.001 %) in sea water, but is found in greater concentration, combined in organic form, in certain seaweeds, in oysters and in cod livers. Crude Chile saltpetre, or caliche contains small amounts of sodium iodate, NalOj. from which iodine can be obtained (see below). Some insoluble iodides, for example liiose of silver and mercury(II), occur in Mexico. Iodine is found in the human body in the compound thyroxin in the thyroid gland deficiency of iodine in diet causes enlargement of this gland (goitre). 

J. F. McClendon, Iodine and the Incidence of Goitre, University of Minnesota Press, Minneapolis, 1939. 

Potassium iodide introduced as a remedy for goitre by J.-F. Coindet (Switzerland), the efficacy of extracts... 

Hyperthyroidism (thyrotoxicosis), defined as excessive thyroid activity, causes a state of thyroid hormone excess (thyrotoxicosis) characterized by an increased metabolic rate, increase in body temperature, sweating, tachycardia, tremor, nervousness, increased appetite and loss of weight. Common causes of hyperthyroidism are toxic multinodular goiter, toxic adenoma or diffuse toxic goitre ( Graves disease). Antithyroid diugs (methimazol, carbimazole, propylthiouracil) block thyroid hormone production and are hence suitable for the treatment of hyperthyroidism. 

Thyroid autonomy appears as a solitary toxic nodule or toxic multinodular goitre. In toxic thyroid, the nodule s synthesis and secretion of thyroid hormones is autonomous from the thyroid-stimulating hormone (TSH), which is produced in the pituitary gland. Accordingly TSH is suppressed and the extranodular thyroid tissue is functionally downregulated. Thyroid autonomy occurs frequently in iodine-deficient countries, whereas it is much less common in iodine-sufficient areas. Constitu-tively activating mutations in the TSH receptor and in the Gs a protein are the major molecular aetiology of toxic thyroid nodules. 

Several trace elements are essential for a healthy life. One example is iodine, which is needed to make the thyroid hormone. An iodine deficiency leads to goitre. This disease was once called Derbyshire throat as it was once common in that county. Goitre was common in inland areas where the soil is low in iodine and access to seafood is poor. 

Ermans AM, Nbulamoko NM, Delange F, et al., eds. 1980. Role of cassava in the etiology of endemic goitre and cretinism. Ottawa, Canada International Development Research Centre, 1-182. 

Clinically she had a fixed stare and swelling at the front of the neck (goitre). The diagnosis of thyrotoxicosis was confirmed by the results of a blood test which showed an undetectable concentration of TSH but markedly raised T3 result. The very low TSH is due to a normal negative feedback response to the raised tri-iodothyronine concentration. 

Iodine is essential in the mammalian diet to produce the thyroid hormone thyroxine deficiency in humans causes goitre. Collectively, deficiencies of iodine, iron, zinc and vitamin A in humans are thought to be at least as widespread and debilitating as calorie deficiencies (Welch and Graham, 1999). The main source of iodine in soils is oceanic salts rather than parent rock, and so deficiency is most widespread in areas remote from the sea (Fuge, 1996). In principle deficiency is easily corrected with dairy supplements. However in practice this is not always feasible. Addition of iodate to irrigation water has successfully corrected widespread iodine deficiency in parts of China where the usual methods of supplementation had failed (Cao et al., 1994 Jiang et al 1997). However there is not much information on the behaviour of iodine in soil and water systems. 

A deficiency of iodine results iu insufficient synthesis of thyroxine and a low plasma level, so that secretion of TSH is increased in an attempt to stimulate synthesis but this results in enlargement of the thyroid gland (goitre). Iodine deficiency in pregnancy impairs brain development in the foetus, causing mental retardation (known as cretinism). Indeed iodine deficiency is one of the major public health issues worldwide an estimated 200 million people are affected. 

A list of minerals, sources and a summary of some roles are given in Table 15.4. Shortage of some of these minerals in the diet causes well-known and well-defined deficiency diseases such as anaemia, due to lack of iron, and goitre, due to lack of iodine. As with vitamins, partial deficiencies... 

Many of the adverse effects of lithium can be ascribed to the action of lithium on adenylate cyclase, the key enz)nne that links many hormones and neurotransmitters with their intracellular actions. Thus antidiuretic hormone and thyroid-stimulating-hormone-sensitive adenylate cyclases are inhibited by therapeutic concentrations of the drug, which frequently leads to enhanced diuresis, h)rpoth)n oidism and even goitre. Aldosterone synthesis is increased following chronic lithium treatment and is probably a secondary consequence of the enhanced diuresis caused by the inhibition of antidiuretic-hormone-sensitive adenylate cyclase in the kidney. There is also evidence that chronic lithium treatment causes an increase in serum parathyroid hormone levels and, with this, a rise in calcium and magnesium concentrations. A decrease in plasma phosphate and in bone mineralization can also be attributed to the effects of the drug on parathyroid activity. Whether these changes are of any clinical consequence is unclear. 

Smith AG et al Goitre and wasting induced in hamsters by hexachlorobenzene. Arch Toxicol 60 343-349, 1987... 

Bedello PG, Goitre M, Roncarolo G Contact dermatitis to rhodium. Contact Derm 17 111-112, 1987... 

The onset of effect of these drugs is slow 2-A weeks is required before stored hormons are depleted and clinical signs of improvement are observed. Short-term treatment is indicated to prepare patients for surgery or radioiodine therapy, while long-term treatment is indicated for cases inappropriate for surgery or radioactive modalities or where medical therapy alone is used. Usually the patient is advised to continue treatment for 1-2 years spontaneous remission occurs in about 50% of cases treated in this way. There is no way to predict remission confidently, however hormone levels, TSAb titer, and goitre size are useful guides. 

Evidence from three randomized controlled trials suggests that the optimal duration of treatment for the titration regimen is 12-18 months, and for the block-replace regimen is 6-12 months. However, people frequently relapse when treatment is stopped. People most likely to achieve remission are those with mild disease and small goitres. This approach is sometimes more convenient for the patient, with greater stability of thyroid function, though it cannot be used in pregnancy. 

Iodides should not be used alone since the normal gland will escape from iodide blockade in 2-8 weeks. Chronic use in pregnancy is not recommended because it crosses placenta and cause fetal goitre. Iodide treatment results in high intrathyroidal iodide content that can delay the onset of thioamide therapy or delay the use for radioactive iodine therapy for weeks if not months. Adverse effects include Hodism which is rare and reversible. The clinical symptoms are acneiform rash, sialadenitis, mucous membrane ulceration, conjuctivitis, rhinor-rhoea, metallic taste and rarely anaphylactoid reaction. 

Countries affected by iodine deficiency require to develop national programmes to assess the extent and severity of the problem. Once an IDD control programme is initiated monitoring and evaluation are required. There are three major components needed to meet this goal, namely determination of thyroid size and goitre prevalence, the determination of urinary iodine excretion, and the measurement of thyroid function, including serum TSH levels. 

Based on goitre prevalence (TGR), median UIE level, and the proportion of population with TSH > 5 mU/1, populations can be classified as having no... 

The therapeutic strategy should rely on preventative measures. Endemic goitre and endemic cretinism as well as more subtle deficits of neurological function associated with iodine deficiency have been shown to be prevented with adequate iodine prophylaxis. Adequate and continuous supply is the key to successful prevention programmes. 

It may not be amiss also to notice, that the author of the present volume first employed the hydriodate of potash, as a remedy for goitre, in the year 1816 after having previously ascertained, by experiments upon himself, that it was not poisonous in small doses, as had been... 

Coindet, J.-F., Decouverte d un nouveau remade contre le goitre, Ann. 

Reber, Burkkard, Le docteur Coindet. L Emploi de 1 iode contre le goitre... 

Figure 9. Chromatograms of blank sample (a), standard mixture (b), sample of thyroid from the control group (c), and sample of thyroid of a patient with diagnosed nodular goitre (d) [22].

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