Hypothyroid goiter

Hypothyroidism Goiter (enlarged thyroid gland), decreased reflexes, intolerance of cold weather, depression... 

Euthyroid or hypothyroid goiter can also complicate lithium therapy, although the goiter is seldom of clinical importance and tends to resolve on withdrawal or with thyroxine treatment. In one ultrasound study, there was a... 

De Wolf D, De Schepper J, Verhaaren H, Deneyer M, Smitz J, Sacre-Smits L. Congenital hypothyroid goiter and amiodarone. Acta Paediatr Scand 1988 77(4) 616-8. 

Neutropenia, hypochromic anemia, osteoporosis, decreased hair and skin pigmentation dermatitis, anorexia, diarrhea Hypothyroid goiter, hypothyroidism... 

Euthyroid goiter or hypothyroid goiter, possibly with increased TSH and reduced thyroxine levels... 

Perchloric acid s corrosive properties and ability to cause tissue oxidation are mechanisms of toxicity. Perchlorate (CIOT) disrupts endocrine homeostasis by competitively inhibiting the transport of iodide (I ) into the thyroid through the sodium iodide symporter. Potential human health risks exist from chronic exposure to perchlorate via drinking water. Such risks may include hypothyroidism, goiter, and mental retardation (if exposure occurs during critical periods in neurodevelopment). 

Iodine Hypothyroid goiter, neuromuscular impairment, deaf-mutism, increased embryonic and postnatal mortality, cognitive impairment, impaired fertility, cretinism (severe cases) Thyrotoxicosis nodular goiter, weight loss, tachycardia, muscle weakness, warm skin Decreased long-term inadequate intake... 

Long-term therapy is contraindicated, because iodides will cross the placenta and into breast milk, causing hypothyroidism (goiter) in the fetus and neonate. Short, intensive therapy for thyrotoxic crisis may be utilized without adverse effects to the fetus. 

Levothyroxine treatment Overt or subclinical hypothyroidism Goiter in euthyroid autoimmunthyroiditis... 

The endocrine implications of iodine deficiency can be largely discussed with regard to the presence of cretinism, neonatal hypothyroidism, goiter rates, thyroid dysfunction... 

Iodine Iodized salt, fish, dairy products Component of thyroid hormones Hypothyroidism, goiter... 

Hypothyroidism, 1471,1473,1485-1489,2423 Hypothyroidism goiters, 2422 Hypoxia, 3706, 3707, 3712, 3722 Hypoxia-inducible factor-1 alpha, 1446 Hypoxia-inducible factor-1-subunit alpha (HIF-la), 1446, 2204 Hypoxic, 1455 Hypusine, 1272 Hyrtios, 727... 

Iodine. Of the 10—20 mg of iodine in the adult body, 70—80 wt % is in the thyroid gland (see Thyroid and antithyroid preparations). The essentiahty of iodine, present in all tissues, depends solely on utilisation by the thyroid gland to produce thyroxine [51-48-9] and related compounds. Well-known consequences of faulty thyroid function are hypothyroidism, hyperthyroidism, and goiter. Dietary iodine is obtained from eating seafoods and kelp and from using iodized salt. 

Myxedema and goiter are the main conditions for which thyroid preparations are indicated. The treatment of cretinism is difficult because it is recognized only at or after birth. Even if this disease could be diagnosed m utero, thyroid hormones do not readily cross the placental barrier. In addition, the fetus, as does a premature infant, rapidly deactivates the thyroid hormones. The halogen-free analogue DlMlT [26384-44-7] (3), which is resistant to fetal deiodinases, may prove useful for fetal hypothyroidism (cretinism). 

Lithium. In the lithium carbonate treatment of certain psychotic states, a low incidence (3.6%) of hypothyroidism and goiter production have been observed as side effects (6,36) (see Psychopharmacologicalagents). It has been proposed that the mechanism of this action is the inhibition of adenyl cyclase. Lithium salts have not found general acceptance in the treatment of hyperthyroidism (see Lithiumand lithium compounds). 

Figure 42-11. Model of iodide metabolism in the thyroid follicle. A follicular cell is shown facing the follicular lumen (top) and the extracellular space (at bottom). Iodide enters the thyroid primarily through a transporter (bottom left). Thyroid hormone synthesis occurs in the follicular space through a series of reactions, many of which are peroxidase-mediated. Thyroid hormones, stored in the colloid in the follicular space, are released from thyroglobulin by hydrolysis inside the thyroid cell. (Tgb, thyroglobulin MIT, monoiodotyrosine DIT, diiodotyro-sine Tj, triiodothyronine T4, tetraiodothyronine.) Asterisks indicate steps or processes that are inherited enzyme deficiencies which cause congenital goiter and often result in hypothyroidism.

Lithium is concentrated in the thyroid gland and can impair thyroid hormone synthesis. Although goiter is uncommon, as many as 30% of patients develop at least transiently elevated thyroid-stimulating hormone values. Lithium-induced hypothyroidism is not usually an indication to discontinue the drug. Patients can be supplemented with levothyroxine if continuation of lithium is desired.30... 

Subtotal thyroidectomy is indicated in patients with very large goiters and thyroid malignancies and those who do not respond or cannot tolerate other therapies. Patients must be euthyroid prior to surgery, and patients often are administered iodide preoperatively to reduce gland vascularity. The overall surgical complication rate is 2.7%. Postoperative hypothyroidism occurs in 10% of patients who undergo subtotal thyroidectomy. 

When lithium is to be used during pregnancy, it should be used at the lowest effective dose in order to avoid floppy infant syndrome, hypothyroidism, and nontoxic goiter in the infant. 

Up to 30% of patients on maintenance lithium therapy develop transiently elevated serum concentrations of thyroid-stimulating hormone, and 5% to 35% of patients develop a goiter and/or hypothyroidism, which is dose-related and more likely to occur in women. This is managed by adding levothyroxine to the regimen. 

There have been occasional case-reports of infants with goiter and hypothyroidism associated with soy-based infant formula consumption (Tuohy, 2003). There has been one case control study, by Fort et al. (1990), which suggested a higher prevalence of soy-based formula feeding in infants with subsequent autoimmune thyroid disease. However, an alternative explanation may be a greater tendency for atopic infants (who may be more likely to be fed soy-based infant formulas) to have such antibodies. 

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. 

Levothyronine has properties of levothyroxine however, it acts faster and binds less with blood proteins. Indications for using levothyronine are the same as with levothyroxine -hypothyroidism, euthyroid goiters, thyroiditis however, its use is considered more appropriate in the first stage of treatment. Synonyms of this drug are tibon, cinomel, tertroxin, and others. 

Methimazole is excreted in breast milk and can cause hypothyroidism and goiter in the newborn child. 

Biosynthetic defects in thyroid hormonogenesis may also result in an inability of the thyroid gland to produce sufficient hormone and may be due to inherited enzymatic deficiencies or the ingestion of natural or therapeutically administered antithyroid agents. An example in the latter category is lithium, widely used to treat psychiatric disorders and associated with the development of hypothyroidism and goiter. It is concentrated by the thyroid, where it inhibits thyroidal I uptake, incorpora-... 

In adults, the signs and symptoms of hypothyroidism include somnolence, slow mentation, dryness and loss of hair, increased fluid in body cavities (e.g., the pericardial sac), low metabolic rate, tendency to gain weight, hyperlipidemia, subnormal temperature, cold intolerance, bradycardia, reduced systolic and increased diastolic pulse pressure, hoarseness, muscle weakness, slow return of muscle to the neutral position after a tendon jerk, constipation, menstrual abnormalities, infertility, and sometimes myxedema (hard edema of subcutaneous tissue with increased content of proteoglycans in the fluid). A goiter (i.e., enlargement of the thyroid gland) may be present. 

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