Surgery, thyroid disease

Falk SA. Thyroid disease Endocrinology, surgery, nuclear medicine, and radiotherapy. 2nd ed. Philadelphia Lippincott-Raven Publishers, 1997. 

The major therapies available for Graves disease are surgery, thyroid-suppressant drugs, and radioactive iodine in sufficient dosage to destroy the gland. Ipodate—an iodine-containing x-ray contrast material—and beta-blockers are of value in severe thyrotoxicosis. 

Studies on thyroid tissue obtained at surgery of Benign thyroid disease Malignant thyroid disease... 

L0W-T3 syndrome is the principal and most common alteration ofTH metabolism found in patients known to have another (i.e., non thyroidal) disease. Regarding cardiac disorders, low-T3 syndrome has been documented in patients with various heart diseases including congestive HF (Hamilton et al., 1990) and acute myocardial infarction (Friberg et al, 2002), as well as after cardiac surgery in both adults and children (Holland et al., 1991 Murzi et al, 1995). The incidence of low-T3 syndrome increases with the severity of the disease and afflicts up to 20—30% of the total cardiac population (Hamilton et al., 1990 lervasi et al, 2003). Several factors contribute to thyroid abnormalities (1) inhibition of the activity of Type 1 deiodinase (2) decreased transport of T4 into tissues and probably (3) reduced activity of Type 2 deiodinase, believed to be responsible for local cellular demand for T3. 

Large doses of iodide inhibit the synthesis and release of thyroid hormones. Serum T4 levels may be reduced within 24 hours, and the effects may last for 2 to 3 weeks. Iodides are used most commonly in Graves disease patients prior to surgery and to quickly reduce hormone release in patients with thyroid storm. Potassium iodide is administered either as a saturated solution (SSKI) that contains 38 mg iodide per drop or as Lugol s solution, which contains 6.3 mg iodide per drop. The typical starting dose is 120 to 400 mg/day. Iodide therapy should start 7 to 14 days prior to surgery. Iodide should not be... 

Iodides are often used as adjunctive therapy to prepare a patient with Graves disease for surgery, to acutely inhibit thyroid hormone release and quickly attain the euthyroid state in severely thyrotoxic patients with cardiac decompensation, or to inhibit thyroid hormone release after RAI therapy. 

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. 

In the adult population, the prevalence of overt hypothyroidism is 19 per 1000 women and 1 per 1000 men with annual incidence of overt hypothyroidism is 4 per 1000 women and 0.6 per 1000 men. Subclinical hypothyroidism is also more common in women, the incidence increases with age, with up to 10% of women older than 60 years having an increased thyroid-stimulating hormone concentration. Subclinical hypothyroidism is more common in people who have been treated for hyperthyroidism with radioactive iodine or surgery, and in those with organ-specific autoimmune diseases, such as pernicious anaemia, type 1 diabetes mellitus, or Addison s disease. 

Other reported side effects include vomiting, salivation, lacrimation, shivering, skin rash, and an interaction with thyroid preparations that may lead to hypertension and tachycardia. Ketamine also may raise intracranial pressure and elevate pulmonary vascular resistance, especially in children with trauma or congenital heart disease. Increases in intraocular pressure also may occur, and vigilance is required if ketamine is used in ocular surgery. 

Thyroid scans with 1l]I are useful in determining the activity of thyroid nodules in the intact thyroid gland. A nonradioactive, cold nodule indicates a higher risk of thyroid carcinoma, but the scan alone is not recommended as a technique of selecting patients for surgery. After removal of a thyroid carcinoma, a scan of the neck may demonstrate areas of increased activity in the cervical lymph nodes and other organs, indicating metastatic disease. 

The use of iodine has been held responsible for the increasing frequency of relapse of Graves disease in the USA. Treatment of more severe cases of iodine-induced hyperthyroidism can be difficult, as thyroid synthesis inhibitors are not immediately active and 131I cannot be used because of low thyroid uptake. The carefully supervised combination of perchlorate and methimazole is effective (40), but surgery has also occasionally been advocated. 

There is an increased incidence of late hypothyroidism in patients with autoimmune hyperthyroidism, but the risk increases markedly after extensive thyroid surgery and especially after I treatment. Analysis of the cumulative incidence of hjrpothjroidism shows two phases an early phase of radiation death of thyroid cells, depending on the I dosage and occurring during the first 1-2 years after treatment a second period of a lower (0.5-3.5% per year) but hfe-long risk of developing hypothyroidism for a variety of reasons (natural history of the disease, autoimmune processes) (see Table 1) (12-14). 

---