Thyroidectomy

Antithyroid drugp or thyroid antagonists are used to treat hyperthyroidism. In addition to the antithyroid drugs, hyperthyroidism may be treated by the administration of strong iodine solutions, use of radioactive iodine (131I), or by surgical removal of some or almost all of the tiiyroid gland (subtotal thyroidectomy). 

Subtotal thyroidectomy is indicated in patients with very large goiters and thyroid malignancies and those who do not respond or cannot tolerate other therapies. Patients must be euthyroid prior to surgery, and patients often are administered iodide preoperatively to reduce gland vascularity. The overall surgical complication rate is 2.7%. Postoperative hypothyroidism occurs in 10% of patients who undergo subtotal thyroidectomy. 

A patient becomes markedly tetanic following a recent thyroidectomy This symptom can be rapidly reversed by the administration of... 

A 29-year-old female who takes levothyroxine following her thyroidectomy becomes pregnant If the dosage is not changed, she will become... 

A 36-year-olcl male has had a thyroidectomy and now requires maintenance therapy Which of the following is the drug of choice ... 

The answer is c. (Hardman, p 15230 Administration of intravenous CaG would immediately correct the tetany that might occur in a patient in whom a thyroidectomy was recently performed. Parathyroid hormone would act more slowly but could be given for its future stabilizing effect. Long-term control of a patient after a thyroidectomy can be obtained with vitamin D and dietary therapy Calcitonin is a hypocalcemic antagonist of parathyroid hormone. Plicamycin (mithramycin) is used to treat Paget s disease and hypercalcemia. The dose employed is about one-tenth the amount used for plicamycin s cytotoxic action. 

TSH is approved for medical use as a diagnostic aid in the detection of thyroid cancer/thyroid remnants in post-thyroidectomy patients. Thyroid cancer is relatively rare, exhibiting highest... 

Rozman, K., T. Rozman, and H. Greim. 1984. Effect of thyroidectomy and thyroxine on 2,3,7,8-tetrachlorod-ibenzo-p-dioxin (TCDD) induced toxicity. Toxicol. Appl. Pharmacol. 72 372-376. 

If thyroidectomy is planned, propylthiouracil (PTU) or methimazole (MMI) is usually given until the patient is biochemically euthyroid (usually 6 to 8 weeks), followed by the addition of iodides (500 mg/day) for 10 to 14 days before surgery to decrease the vascularity of the gland. Levothy-roxine may be added to maintain the euthyroid state while the thiona-mides are continued. 

Yarbrough JD, Grimley JM, Thottassery JV. 1992. Mirex-induced adaptive liver growth in rats subjected to thyroidectomy. Hepatology 15(5) 923-927. 

Figure 16.14 Effect of thyroidectomy on survival of rats during starvation. Thyroidectomy protects rats from starvation that is, the number or rats surviving prolonged starvation is much larger when the thyroid gland is removed (Goldberg et al. 1978).

Hyperthyroidism Long-term therapy may lead to disease remission. Also used to ameliorate hyperthyroidism in preparation for subtotal thyroidectomy or radioactive iodine therapy. 

Propylthiouracil is also used when thyroidectomy is contraindicated or not advisable. 

TSH is approved for medical use as a diagnostic aid in the detection of thyroid cancer/thyroid remnants in post-thyroidectomy patients. Thyroid cancer is relatively rare, exhibiting the highest incidence in adults, particularly females. First-line treatment is surgical removal of all or most of the thyroid gland (thyroidectomy). This is followed by thyroid hormone suppression therapy, which entails administration of T3 or T4 at levels sufficient to maintain low seum TSH levels through the negative feedback mechanism mentioned earlier. TSH suppression is required... 

Three main modalities of therapy should be considered for patients with thyrotoxicosis, namely, medical therapy, surgical thyroidectomy, and radioiodine. The choice between these therapies should be dictated by the clinical nature of the disease, the patient s general health, her desire for pregnancy or need to care for young children, and overall patient preference. Treatment is initially monitored by free thyroxine (T4) values, as suppression of thyroid-stimulating hormone (TSH) may persist for months despite adequate management. 

Surgery is usually a near-total thyroidectomy, with main indications being suspected coexistent thyroid carcinoma, solitary toxic nodule, large goiter, failed medical treatment, patient preference and occasionally in pregnancy if adverse effects from antithyroid dmgs occur. 

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. 

The 3-blockers significantly reduce the peripheral manifestations of hyperthyroidism, particularly elevated heart rate, increased cardiac output, and muscle tremors. Although the 3-blockers can improve the clinical status of the hyperthyroid patient, the patient remains biochemically hyperthyroid. The 3-blockers should not be used as the sole form of therapy in hyperthyroidism. They are most logically employed in the management of hyperthyroid crisis, in the preoperative preparation for thyroidectomy, and during the initial period of administration of specific antithyroid drugs (see Chapter 65). 

Evaluating recurrent or residual follicular cell tumors (treated previously by thyroidectomy and radioiodine ablation) when serum thyroglobulin >10 ng/ml and 2 1 whole-body scan is negative (October 2003) Detecting pretreatment metastases in newly diagnosed cervical cancer after negative conventional imaging (January 2005)... 

The hormones of adrenal glands, thyroid and pancreas exert various effects on the metabolism of drugs. Adrenalectomy of certain species e.g. rat impairs the metabolism of certain drugs, which can be reversed by administration of cortisone or prednisolone. Administration of ACTH, adrenaline or thyroxine impairs the hepatic microsomal metabolism of drugs. Thyroidectomy reduces the... 

It is used in hyperthyroidism due to Graves disease, prior to surgical treatment of hyperthyroidism i.e., thyroidectomy. It is also used in the treatment of paroxysmal tachycardia and intractable congestive cardiac failure. 

Iodine is used in thyroid storm, hyperthyroidism, preoperatively before thyroidectomy and prophylaxis of endemic goitre. Iodine is also useful as antiseptic and in expectorants. 

Radioactive iodine is indicated in hyperthyroidism due to Graves disease or toxic nodular goitre and also used as palliative therapy after thyroidectomy for papillary carcinoma of thyroid. 

Clifton, K.H. and Crowley, J.J. (1978). Effects of radiation type and dose and the rate of glucocorticoids, gonadectomy, and thyroidectomy in mammary tumor induction in mammotrophic-secreting pituitary tumor-grafted rats, Cancer Res. 38,1507. 

Hypothyroidism, a condition in which the circulating concentrations of thyroid hormones are too low, is the most prevalent thyroid disease. Primary hypothyroidism, the commonest form, is an autoimmune disease (Hashimoto s thyroiditis) often associated with goitre. Like other autoimmune diseases, it is more prevalent in women (4 per 1000) than in men (1 per 1000). Other causes include thyroidectomy, radioac tive ablation and, in some countries, iodine deficiency. Hypothyroidism can also be caused by several drugs, including lithium, interleukin-2 and interferon. Secondary hypothyroidism is a disease caused by decreased secretion of TSH by the pituitary. 

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