Hyperthyroidism surgery

Three common treatment modalities are used in the management of hyperthyroidism surgery, antithyroid medications, and radioactive iodine (RAI) (Table 73-5). The overall therapeutic objectives are to eliminate the excess thyroid hormone and minimize the symptoms and long-term consequences of hyperthyroidism. Therapy must be individuahzed based on the type and severity of hyperthyroidism, patient age and gender, existence of nonthyroidal con-... 

Complications of surgery include persistent or recurrent hyperthyroidism (0.6% to 18%), hypothyroidism (up to about 49%), hypoparathyroidism (up to 4%), and vocal cord abnormalities (up to 5%). The frequent occurrence of hypothyroidism requires periodic follow-up for identification and treatment. 

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. 

After therapy (thionamides, RAI, or surgery) for hyperthyroidism has been initiated, patients should be evaluated on a monthly basis until they reach a euthyroid condition. 

Prealbumin (trans- thyretin) 2-3 Binds triiodothyronine and to a lesser extent thyroxine carrier for retinolbinding protein Kidney dysfunction Cirrhosis, hepatitis, stress, inflammation, surgery, hyperthyroidism, cystic fibrosis, kidney dysfunction, zinc deficiency... 

The complications following surgery include haemorrhage, wound infection, recurrent laryngeal nerve damage, and transient (up to 20% of cases) or permanent (2%) hypocalcaemia. After near-total thyroidectomy relapse of hyperthyroidism should be rare, and this operation has largely replaced the older approach of sub-total thyroidectomy which had higher relapse rates. 

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. 

The most serious complication of hyperthyroidism is thyroid storm (thyrotoxic crisis). This is an acute exacerbation of hyperthyroidism with marked tachycardia, fever, mental status changes and haemodynamic collapse. It is usually precipitated by acute illness, trauma, parturition or surgery, especially of the thyroid gland. The mortality rate is 20-30%, even with aggressive treatment, due to cardiac failure, arrhythmias or hyperthermia. 

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. 

Leukemia does not occur more often in patients treated with 131I for hyperthyroidism than in similar patients treated by surgery. After use of the high doses used in the treatment of thyroid cancer there was a definite increase in the incidence of leukemia (18). 

Pregnancy. If a pregnant woman has hyperthyroidism (2/1000 pregnancies) she should be treated with the smallest possible amount of these drugs because they cross the placenta with overtreatment fetal goitre occurs. Surgery in the second trimester may be preferred to continued drug therapy. 

Preparation of hyperthyroid patients for surgery can be satisfactorily achieved by making them euthyroid with one of the above drugs plus a P-adrenoceptor blocker for comfort (see below) and safety, and adding iodide for 7-10 days before operation (not sooner) to reduce the surgically inconvenient vascularity of the gland. 

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). 

The thioamides are often used as primary therapy for hyperthyroidism. They are also used as adjunctive therapy to achieve euthyroidism in patients prior to surgery or radioactive iodine therapy. The thioamides primarily inhibit... 

Hyperthyroidism (excessive production of thyroid hormones) asually requires surgery, but before. surgery the patient mu.st be prepared by preliminary abolition of the hyper-thyroidi.sm through the use of antithyroid drugs. Thiourea and related eompounds. show an antithyroid activity, but they arc too toxic for clinical use. The more useful drugs are 2-thiouracil derivatives and a closely related 2-thioimidazolc derivative. All of these appear to have a similar mechanism of action (i.c.. prevention of the iodination of the precursors of thyroxine and triiodothyronine). The main difference in the compounds lies in their relative toxieities. 

Acute symptomatic hypocalcemia may be seen in hospitalized patients for various reasons. Rapid remineralization of bone after surgery for primary hyperparathyroidism (hungry bone syndrome), treatment for hyperthyroidism, or treatment for hematological malignancy may result in hypocalcemia. Acute hemorrhagic or edematous pancreatitis is frequently complicated by hypocalcemia. Vitamin D deficiency may also be associated with hypocalcemia because of impaired intestinal absorption of calcium and skeletal resistance to PTH. Osteomalacia and rickets are discussed in a later section of this chapter. 

Ljunggren JG, Torring O, Wallin G, et al. Quahty of life aspects and costs in treatment of Graves hyperthyroidism with antithyroid drugs, surgery, or radioiodine Results from a prospective, randomized study. Thyroid 1998 8 653-659. 

Yusho and Yu-Cheng Exposures. In a case-control study of the Taiwan Yu-Cheng cohort, 795 exposed subjects and 693 sex- and age-matched controls were interviewed for information about health and medical history (Guo et al. 1999). The odds ratio (OR) for goiter (men and women combined) was 2.8 (Cl, 1.2-7.1) and 4.0 (Cl, 1.5-13.9) for goiter that was treated with medication or surgery. The ORs for hypothyroidism or hyperthyroidism were not significant (males, 0.95 females, 1.7). 

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