Thyroid insufficiency

Thyroid-stimulating hormone can be used clinically to test thyroid function but has not found practical apphcation in the treatment of human thyroid insufficiency. Direct replacement therapy with thyroid hormone is easy and effective, owing to a simple molecular stmcture. TSH has been used in the veterinary treatment of hypothyroidism, and preparations of TSH ate produced by Cooper Animal Health, Inc. and Armour Pharmaceuticals. 

Consensus Statement 2. American Thyroid Association statement on early maternal thyroidal insufficiency Recognition, clinical management and research directions. Thyroid 2005 15 77. 

Scott et al. 1982). Thyroid insufficiency can cause considerably plumage changes in chickens. In the Brown Leghorn male, the testes remain small and free of spermatozoa, the comb decreases in size, and the male plumage is lost (Underwood 1981). Iodine deficiency appears rapidly when poultry diets contain goitrogenic substances (McDowell 1992, Kroupova et al. 1997). 

Trimester-specific reference intervals for thyroid functions are especially important, since thyroid insufficiency may... 

The mean UIE of the pregnant women, in the first trimester of gestation, was under the critical level of 200 pg/1 (15% of them were in severe deficiency), while 21.4% of their newborns had TSH over 5mU/l. These data, which are worse than that of the last decade (Enguix et al., 1995), describe the researched zone as in area of a moderate deficiency, based on the criteria of the WHO (2001). One quarter of the pregnant women had their fT4 lower than the tenth percentile. Seven of them (11.2%) were hypothyroid, but none showed clinical evidence about their thyroid insufficiency. A similar observation was referred to by... 

This is further indicated by evidence of the relation of maternal thyroxine levels to the risk of cretinism and the psychomotor defect from studies in Papua New Guinea (26). The subsequent lack of fetal thyroid hormones due to the inadequate supply of iodine in iodine deficiency would exacerbate the effects of maternal thyroid insufficiency and the combination of effects, which were represented experimentally in the sheep by maternal thyroidectomy before conception (21) combined with fetal thyroidectomy at 98 days (12), might be expected to produce the multiple defects of neurological cretinism. 

If the necessary iodine input is insufficient the thyroid gland enlarges in an attempt to gamer more iodine addition of 0.01% Nal to table salt (iodized salt) prevents this condition. Tincture of iodine is a useful antiseptic. 

Primary or secondary adrenal cortical insufficiency, congenital adrenal hyperplasia, nonsuppressive thyroiditis, hypercalcemia associated with cancer... 

Patients with autoimmune adrenal insufficiency may have other autoimmune disorders such as type 1 diabetes mel-litus and autoimmune thyroiditis. 

Corticosteroids are generally recommended, but there is no convincing evidence of adrenocortical insufficiency in thyroid storm their benefits may be attributed to their antipyretic action and stabilization of blood pressure. 

The Mann et al. (1985) study is limited in that too few animals were used, organs other than the liver were not adequately evaluated, and only males were studied. Although an adequate acute-duration oral study would be useful to corroborate or refute the thyroid effects seen in the Mann et al. (1985) study, this does not represent a data need, since an acute oral MRL has been derived. Ingestion of contaminated drinking water is expected to be the predominant route of exposure for individuals living in the vicinity of hazardous waste sites. However, acute-duration inhalation and dermal studies in animals are needed to assess the potential toxicity of di- -octylphthalate following exposure via these routes because there are insufficient pharmacokinetic data available to support the extrapolation of data obtained after oral administration to other routes of exposure. 

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. 

Clinical use of amiodarone is limited because of its high toxicity, which consists of cardiac block, bradycardia, cardiac insufficiency, damaged thyroid gland function, neuropathology, and increased sensitivity to light, all of which significantly limit use of amiodarona, and it is only used in therapy for extremely serious tachyarrhythmias such as reoccurring ventricular fibrillation and hemodynamic unstable ventricular tachycardia, and only under supervision of a physician in a clinical situation. Synonyms of amiodarone are cordarone, rythmarone, and others. 

Diseases associated with thyroid glands are the result of either excess production of thyroid hormone (hyperthyroidism), or its insufficiency (hypothyroidism). Both cases can result in a goiter. 

Endocrine disorders Primary or secondary adrenal cortical insufficiency (hydrocortisone or cortisone is the drug of choice synthetic analogs may be used in conjunction with mineralocorticoids in infancy, mineralocorticoid supplementation is important) congenital adrenal hyperplasia nonsuppurative thyroiditis hypercalcemia associated with cancer. 

Endocrine disorders Thyroid hormone therapy in patients with concomitant diabetes mellitus or insipidus or adrenal insufficiency (Addison disease) exacerbates the intensity of their symptoms. 

Autoimmune polyglandular syndrome-Chron c autoimmune thyroiditis may occur in association with other autoimmune disorders. Treat patients with concomitant adrenal insufficiency with replacement glucocorticoids prior to initiation of treatment. Failure to do so may precipitate an acute adrenal crisis when thyroid hormone therapy is initiated. Patients with diabetes mellitus may require upward adjustments of their antidiabetic therapeutic regimens. Nontoxic diffuse goiter or nodular thyroid disease Use caution when administering levothyroxine to patients with nontoxic diffuse goiter or nodular thyroid disease in order to prevent precipitation of thyrotoxicosis. If the serum TSH is already suppressed, do not administer levothyroxine. 

A normal rate of thyroid hormone synthesis depends on an adequate dietary intake of iodine. Iodine is naturally present in water and soil, although some soils contain very low amounts. As a result, seafood is a more reliable source of iodine than crop plants. Approximately 1.6 billion people in more than 100 countries live in areas where natural sources of dietary iodine intake are marginal or insufficient. A minimum of 60 j.g of elemental iodine is required each day for thyroid hormone synthesis, and at least 100 j.g/day is required to eliminate thyroid follicular cell hyperplasia and thyroid enlargement (i.e., iodine deficiency goiter). 

In patients with longstanding hypothyroidism and those with ischemic heart disease, rapid correction of hypothyroidism may precipitate angina, cardiac arrhythmias, or other adverse effects. For these patients, replacement therapy should be started at low initial doses, followed by slow titration to full replacement as tolerated over several months. If hypothyroidism and some degree of adrenal insufficiency coexist, an appropriate adjustment of the corticosteroid replacement must be initiated prior to thyroid hormone replacement therapy. This prevents acute adrenocortical insufficiency that could otherwise arise from a thyroid hormone-induced increase in the metabolic clearance rate of adrenocortical hormones. 

An adequate dietary intake of iodine is essential to prevent hypothyroidism. In many areas of the world, dietary iodine intake is insufficient and must be supplemented. There is another element in which a dietary intake may be insufficient that is also associated with thyroid hormone metabolism. This element is... 

Contraindications to interferon alfa therapy include hepatic decompensation, autoimmune disease, and history of cardiac arrhythmia. Caution is advised in the setting of psychiatric disease, epilepsy, thyroid disease, ischemic cardiac disease, severe renal insufficiency, and cytopenia. Alfa interferons are abortifacient in primates and should not be administered in pregnancy. Potential drug-drug interactions include increased theophylline levels and increased methadone levels. Co-administration with didanosine is not recommended because of a risk of hepatic failure, and co-administration with zidovudine may exacerbate cytopenias. 

---