Hyperthyroidism toxic nodule

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. 

Radioactive iodine ( 1) Cure of hyperthyroidism Most cost effective Permanent hypothyroidism almost inevitable Might worsen ophthalmopathy Pregnancy must be deferred for 6-12 months no breast-feeding Small potential risk of exacerbation of hyperthyroidism Best treatment for toxic nodules and toxic multinodular goiter... 

U patients with solitary autonomously functioning nodules were examined. None was removed surgically. 7 of these patients were also hyperthyroid and in 5 of these the toxic nodule had measurable iodine stores with count rates ranging from 400 to 1000 per 100 seconds. The other 2 toxic nodules had undetectable stable iodine stores despite good radioiodine uptake. On the other hand, the contralateral suppressed lobe had detectable iodine stores in 3 but not in 4 of the toxic patients. 

The common causes of thyrotoxicosis are shown in Table 41-6.29,30 Thyrotoxicosis can be related to the presence or absence of excess hormone production (hyperthyroidism). Graves disease is the most common cause of hyperthyroidism. Thyrotoxicosis in the elderly is more likely due to toxic thyroid nodules or multinodular goiter than to Graves disease. Excessive intake of thyroid hormone may be due to overtreatment with prescribed therapy. Surreptitious use of thyroid hormones also may occur, especially in health professionals or as a self-remedy for obesity. Thyroid hormones can be obtained easily without a prescription from health food stores or Internet sources. 

An autonomous thyroid nodule (toxic adenoma) is a discrete thyroid mass whose function is independent of pituitary control. Hyperthyroidism usually occurs with larger nodules (i.e., those greater than 3 cm in diameter). 

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. 

In older patients toxic multinodular goiter typically presents as longstanding asymptomatic multinodular goiters. Functional autonomy of the nodules develops over time by an unknown mechanism and causes the disease to move from the nontoxic to the toxic phase. The onset of hyperthyroidism is gradual, and the symptoms are usually milder than those of Graves disease. 

The treatment aims to correct the symptoms experienced by the patient due to the presence of a toxic adenoma or toxic multinodular goiter. There are two types of symptoms functional ones, which relate to hyperthyroidism and mechanical ones, which are due to the pressure exerted by the goiter or nodule, irrespective of the functional impairment caused. 

From a functional point of view, euthyroid diffuse goiter and hypofunctional thyroid nodules have to be discerned from hyperthyroid conditions, mainly toxic adenoma and toxic multinodular goiter. 

TOXIC NODULAR GOITER. Growth of thyroid nodules sometimes occurs without TSH simulation. In some cases, there may be escape of thyroid hormone production from the control of the pituitary then, the uncontrolled nodules are described as having become autonomous. This condition is more likely to be found in older persons who may have cardiovascular disorders as a consequence, but have none of the other characteristics of hyperthyroidism. 

In the presence of thyroid disease, and in areas with endemic iodine deficiency, suddenly raising daily iodine intake may precipitate hyperthyroidism, and this has been the subject of some concern as salt iodization efforts proceed with fledgling quality assurance. This effect is felt to be related in part to autonomous nodules in the gland that synthesize and release excess thyroid hormone. The exact prevalence of iodine-induced hyperthyroidism in deficient areas is not clear. Many coim-tries initiating salt iodization programs have reported increases in the incidence of toxic nodular goitre and iodine-induced thyrotoxicosis, usually in older people. While this may be a significant clinical problem, the risk is estimated to be between 0.01 and 0.06% and must be... 

---