Hyperthyroidism iodine

Table 4. Iodine Induced Hyperthyroidism Iodine supplementation for endemic iodine-deficiency goiter...

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. 

Hyperthyroidism may be treated in several ways. One of these is interference with the synthesis of the thyroid hormones, possibly by removal of iodine. Thiourea and cyclic thioureas have this effect and of such cyclic compounds, thiouracil (1030 R = H), its 6-alkyl derivatives (1030 R = Me or Pr) and thiobarbital (1031) are effective thyroid drugs. Today only propylthiouracil (1030 R = Pr) is widely used, probably because it has fewer side effects than the others (71MI21302). The thiouracils are made by the Principal Synthesis from a /3-oxo ester (1032 R = H, Me, Pr, etc.) and thiourea (45JA2197) their fine structures are experimentally based (64AF1004). 

Antithyroid drugp or thyroid antagonists are used to treat hyperthyroidism. In addition to the antithyroid drugs, hyperthyroidism may be treated by the administration of strong iodine solutions, use of radioactive iodine (131I), or by surgical removal of some or almost all of the tiiyroid gland (subtotal thyroidectomy). 

Before a patient starts therapy with an antithyroid drug, die nurse obtains a history of the symptoms of hyperthyroidism. It is important to include vital signs, weight, and a notation regarding the outward symptoms of die hyperthyroidism (see Table 51-1) in the physical assessment. If die patient is prescribed an iodine solution, it is essential that die nurse take a careful allergy history, particularly to iodine or seafood (which contains iodine). 

Iodine excess (including radiocontrast, amiodarone) Thyrotoxicosis without hyperthyroidism Subacute thyroiditis Silent (painless) thyroiditis... 

In the hyperthyroid patient, relieving signs and symptoms and achieving a euthyroid state are the desired outcomes. The method of achieving these outcomes may change over time with the use of antithyroid drugs versus radioactive iodine. 

An elevated 24-hour radioactive iodine uptake (RAIU) indicates true hyperthyroidism the patient s thyroid gland is overproducing T4, T3, or both (normal RAIU 10% to 30%). Conversely, a low RAIU indicates that the excess thyroid hormone is not a consequence of thyroid gland hyperfunction but is likely caused by thyroiditis or hormone ingestion. 

Toxic adenomas may result in hyperthyroidism with larger nodules. Because there may be isolated elevation of serum T3 with autonomously functioning nodules, a T3 level must be measured to rule out T3 toxicosis if the T4 level is normal. After a radioiodine scan demonstrates that the toxic thyroid adenoma collects more radioiodine than the surrounding tissue, independent function is documented by failure of the autonomous nodule to decrease its iodine uptake during exogenous T3 administration. 

Blockers are usually used as adjunctive therapy with antithyroid drugs, RAI, or iodides when treating Graves disease or toxic nodules in preparation for surgery or in thyroid storm. /3-Blockers are primary therapy only for thyroiditis and iodine-induced hyperthyroidism. 

Peptides in Human Urine (Skarzynski and Samecka-Keller), 5, 107 Protein Bound Iodine (Chaney), I, 82 Radioactive Iodine-131 in the Diagnosis of Hyperthyroidism, Blood Plasma Levels of (Silver), 1, 111 Transaminase Activities of Serum and Body Fluids, the Clinical Significance of Alterations in (Wroblew-ski), 1, 314... 

Amiodarone (Figure 8.2) is an efficacious drug that causes a number of side-effects. The presence of iodine in the molecule is unusual and hypo- and hyperthyroidism have been reported in patients. Although the loss of iodine is relatively slow the relatively large daily dose size and long half-life of the drug and its de-ethylated metabolite suggest that the presence of iodine in the molecule is responsible for its toxicity [3]. 

In older patients with goiter due to iodine deficiency there is a risk of provoking hyperthyroidism by increasing iodine intake (p. 247) During chronic maximal stimulation, thyroid follicles can become independent of TSH stimulation ( autonomic tissue"). If the iodine supply is increased, thyroid hormone production increases while TSH secretion decreases due to feedback inhibition. The activity of autonomic tissue, however, persists at a high level thyroxine is released in excess, resulting in iodine-induced hyperthyroidism. 

Short-term thyroid suppression (C). Iodine in high dosage (> 6000 pg/d) exerts a transient "thyrostatic effect in hyperthyroid, but usually not in euthyroid, individuals. Since release is also blocked, the effect develops more rapidly than does that of thioamides. 

Blood Plasma Levels of Radioactive Iodine-131 in the Diagnosis of Hyperthyroidism Solomon Silver... 

Drugs used for hyperthyroidism can be classified as drugs that suppress thyroid hormone synthesis in the anterior lobe of the hypophysis, and they consist of diiodotyrosine and iodine, as well as drugs that suppress thyroid hormone synthesis in thyroid glands (propylthiouracil, methylthiouracil, methimazole, and carbimazole). 

Hyperthyroidism Long-term therapy may lead to disease remission. Also used to ameliorate hyperthyroidism in preparation for subtotal thyroidectomy or radioactive iodine therapy. 

Hyperthyroidism is characterized by an enhanced sympathetic activity, especially in the heart. The salutary inhibition of jS-adrenoceptors under these conditions can be achieved by all jS-blocker alike. Some of the clinically used compounds are able to reduce the conversion (de-iodination) of thyroxine (T4) to the active 3,5,3 -Triiodothyronine (T3)... 

Radio-iodine, I, diffusely kills thyroid cells resulting in eventual and inevitable hypothyroidism which often makes substitution with thyroxine necessary. Administered as capsules it is an effective oral treatment for hyperthyroidism. Patient should not be pregnant or become pregnant in the month following treatment. Breast-feeding is contraindicated. Painful radiation thyroiditis may occur. 

Pretreatment with antithyroid drugs is necessary to avoid the risk of thyroid storm (exacerbation of hyperthyroidism with fever and tachycardia) in the following groups the elderly, people with cardiac disease, and people with severe hyperthyroidism. Antithyroid drugs should be stopped at least 4 days before radioactive iodine is given, and restarted no sooner than 3 days after, to permit uptake of the iodine into the thyroid gland. Antithyroid drugs can usually be stopped after 2-6 weeks as the radioactive iodine takes effect. 

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