In hyperthyroidism

Catecholamine receptors are well estabUshed to be altered by a variety of homologous and heterologous influences (104). Thus, in hyperthyroidism, there is an increased level of sympathetic activity associated with increased expression of a- and P-adrenoceptors. 

The selective uptake of iodide ion by the thyroid gland is the basis of radioiodine treatment in hyperthyroidism, mainly with although various other radioactive isotopes ate also used (40,41). With a half-life of eight days, the decay of this isotope produces high energy P-particles which cause selective destmction within a 2 mm sphere of their origin. The y-rays also emitted are not absorbed by the thyroid tissue and are employed for external scanning. 

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. 

Different effects seen among diseases increased risk seen in hyperthyroidism, rheumatoid arthritis, and Crohn s disease but reduced risks seen in ulcerative colitis and possibly adult-onset type 1 diabetes. Limited mechanistic research. 

Carbimazole is an antithyroid drug indicated in hyperthyroidism. It is usually administered as 15 mg daily in the morning. Carbimazole tends to cause agranulocytosis and therefore patients are advised to report immediately any signs of infections, such as sore throat. 

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. 

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