Toxic multinodular goiter

TOXIC UNINODULAR GOITER TOXIC MULTINODULAR GOITER... 

Toxic Uninodular Goiter Toxic Multinodular Goiter... 

Functionally, the state may be compensated up to a certain degree of iodine deficiency and for a considerable period of time, described in clinical terms as euthyroid diffuse or nodular goiter. Functional failure follows only in the presence of severe iodine deficiency, and hypothyroidism may then develop. Much more frequently and somewhat paradoxically, hyperthyroidism ensues after many years of iodine depletion. Rarely, hyperthyroidism may be found in cases of diffuse goiter, which are then termed as diffuse thyroid autonomy. Fiowever, hyperthyroidism frequendy occurs in conjunction with uninodular (toxic adenoma) and multinodular goiters (toxic multinodular goiter). 

Graves disease Hot nodule and toxic multinodular goiter Etiology ... 

Fuhrer D, Krohn K, Paschke R (2005) Toxic Adenoma and toxic Multinodular Goiter. In Braverman, LE Utiger (Hrsg.) RD (eds) Lippincott Williams Wilkins, ISBN 0-7817-5047-4, The Thyroid, 508-518... 

Hyperthyroidism (thyrotoxicosis), defined as excessive thyroid activity, causes a state of thyroid hormone excess (thyrotoxicosis) characterized by an increased metabolic rate, increase in body temperature, sweating, tachycardia, tremor, nervousness, increased appetite and loss of weight. Common causes of hyperthyroidism are toxic multinodular goiter, toxic adenoma or diffuse toxic goitre ( Graves disease). Antithyroid diugs (methimazol, carbimazole, propylthiouracil) block thyroid hormone production and are hence suitable for the treatment of hyperthyroidism. 

Primary hyperthyroidism Graves disease Toxic multinodular goiter... 

RAI is the agent of choice for Graves disease, toxic autonomous nodules, and toxic multinodular goiters. Pregnancy is an absolute contraindication to the use of RAI. 

Gabriel, E. M., Bergert, E. R., Grant, C. S., van Heerden, J. A., Thompson, G. B., and Morris, J. C. (1999) GermUne polymorphism of codon 727 of human thyroid-stimulating hormone receptor is associated with toxic multinodular goiter. J. Clin. Endocrinol. Metab. 84, 3328-3335. 

III.b.1.6. Radioactive iodine. Radioactive iodine (Iodine-131) is a radioactive isotope of iodine, usually taken in an oral solution formulation as sodium 1. Given orally as sodium I, radioactive iodine is rapidly absorbed, concentrated and stored in the thyroid follicles. The therapeutic effect depends on beta-ray emission and destruction of thyroid parenchyma manifests some weeks after treatment. It is relatively safe, cheap, painless and avoids side effects associated with surgery. It is widely regarded as the treatment of choice in adults with toxic multinodular goiter, toxic nodule and people who relapse after a course of antithyroid medication. 

The manifestations of hyperthyroidism depend on the severity of the disease, the age of the patient, the presence or absence of extrathyroidal manifestations, and the specific disorder producing the thyrotoxicosis. Of the various types of hyperthyroidism, only two are common Graves disease and toxic multinodular goiter. Less common causes include toxic adenoma and postpartum thyroiditis, among others. 

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. 

Thyrotoxic crisis, thyroid storm, or accelerated hyperthyroidism is an extreme accentuation of thyrotoxicosis. Although uncommon, this serious complication of hyperthyroidism usually occurs in association with Grave s disease and occasionally with toxic multinodular goiter. 

Toxic multinodular goiter Constitutive activation of adenylyl cyclase [31]... 

Germline polymorphism of codon 727 of human thyroid-stimulating hormone receptor is associated with toxic multinodular goiter. J Clin Endocrinol Metab 84 3328-3335... 

Thyroid disorders. Disturbances in thyroid metabolism can occur at any level of the hypothalams-pituitary-thyroid-peripheral tissue axis. Several of these disorders have been discussed previously. Hyperthyroidism is more prevalent in women than men. The three most common causes of hyperthyroidism are Graves hyperthyroidism, toxic multinodular goiter, and toxic adenoma. The clinical features of hyperthyroidism include hyperkinesis, weight loss, cardiac anomalies (e.g., atrial fibrillation), fatigue, weakness, sweating, palpitations, and nervousness. The typical biochemical laboratory parameters are increased serum free T4 and decreased serum TSH. 

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... 

Siegel RD, Lee SL. Toxic nodular goiter. Toxic adenoma and toxic multinodular goiter. Endocrinol Metab CUn North Am 1998 27 151-168. 

In mild and moderate ID, the prevalence rate of circulating thyroid autoantibodies in the population is also high (Laurberg et ai, 1998 Pedersen et aL, 2003). In such areas, non toxic and toxic multinodular goiters are prevalent and overall hyperthyroidism is more common than hypothyroidism (Laurberg et ai, 1999). Results from areas with severe ID are fimited and might, in some cases, be influenced by the general immunosuppressive effect of malnutrition, which may occur simultaneously (Salabe et al., 1982). 

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. 

The treatment of hyperthyroidism requires differentiation between the various types of hyperthyroidism (Table 81.1). Toxic adenoma and toxic multinodular goiter are the most common causes of hyperthyroidism in iodine-deficient countries, as opposed to Graves disease, which is... 

Patients with toxic adenoma or toxic multinodular goiter, in the absence of symptoms and with TSH well in the euthyroid range, may be monitored without therapy. The therapy can frequently be postponed for many years to a later stage. 

Once the diagnosis and indication for treatment have been established, there are three main options for treating patients with toxic adenoma or toxic multinodular goiter ... 

The main use of antithyroid drugs in toxic adenoma and toxic multinodular goiter is therefore to attain a euthyroid state before the patient may undergo other modes of therapy. Another use is to block iodine uptake prior to the exposure to radiographic contrast agents in patients at risk of iodine-induced hyperthyroidism. 

Combination with levothyroxine, a common practice in treating Graves disease, is prohibited in toxic adenoma and toxic multinodular goiter. 

As for the efficiency of radioiodine treatment, elimination of hyperthyroidism has been reported to be achieved in approximately 90% of the patients with toxic adenoma and 60-80% of patients with toxic multinodular goiter (Dietlein et ai, 2004 Ferrari et al., 1996 Hegedus et ai, 2003 Le Moli et al, 1999 Nygaard et al., 1999 Reiners and Schneider, 2002). 

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