Medical Management of Hyperthyroidism PDF

11/7/23, 2:11 PM Realizeit for Student Medical Management Appropriate treatment of hyperthyroidism depends on the underlying cause and often consists of a combination of therapies, including antithyroid agents, radioactive iodine, and surgery. Treatment of hyperthyroidism is directed toward reduci...

11/7/23, 2:11 PM Realizeit for Student Medical Management Appropriate treatment of hyperthyroidism depends on the underlying cause and often consists of a combination of therapies, including antithyroid agents, radioactive iodine, and surgery. Treatment of hyperthyroidism is directed toward reducing thyroid hyperactivity to relieve symptoms and preventing complications. The use of radioactive iodine is the most common form of treatment for Graves disease. Beta-adrenergic blocking agents (e.g., propranolol, atenolol, metoprolol) are used as adjunctive therapy for symptomatic relief, particularly in transient thyroiditis (Lee & Khardori, 2018). The three treatments (radioactive iodine therapy, antithyroid medications [e.g., thionamides], and surgery) share the same complications: relapse or recurrent hyperthyroidism and permanent hypothyroidism. The rate of relapse increases in patients who have had very severe disease, a long history of dysfunction, ocular and cardiac symptoms, large goiter, or relapse after previous treatment. Patients with Graves disease may sustain remission for up to 12 to 18 months but often experience recurrence within 12 months of treatment (Lee & Khardori, 2018). Radioactive Iodine Therapy Radioactive iodine has been used to treat toxic adenomas, toxic multinodular goiter, and most varieties of thyrotoxicosis and is considered the treatment of choice because a single dose is effective in treating 80% to 90% of cases (Bauerle & Clutter, 2019). Radioactive iodine is contraindicated during pregnancy because it crosses the placenta. Women of childbearing age should be given a pregnancy test 48 hours before administration of radioactive iodine. They should also be instructed to not conceive for at least 6 months following treatment. In addition, breastfeeding for up to 6 weeks prior to radioactive iodine treatment is contraindicated (Lee & Khardori, 2018). The goal of radioactive iodine therapy (131I) is to eliminate the hyperthyroid state with the administration of sufficient radiation in a single dose (Lee & Khardori, 2018). Almost all of the iodine that enters and is retained in the body becomes concentrated in the thyroid gland. Therefore, the radioactive isotope of iodine is concentrated in the thyroid gland, where it destroys thyroid cells without jeopardizing other radiosensitive tissues. Over a period of several weeks, thyroid cells exposed to the radioactive iodine are destroyed, resulting in reduction of the hyperthyroid state and inevitably hypothyroidism. The use of an ablative dose of radioactive iodine initially causes an acute release of thyroid hormone from the thyroid gland and may cause increased symptoms. The patient is observed for signs of thyroid storm (see Chart 45-6), a life-threatening condition manifested by cardiac arrhythmias, fever, and neurologic impairment (Norris, 2019) which may lead to heart failure, circulatory collapse and https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZMyySaAjt8dTx3FnIrt15HOKniKu5nqplgCFS7%2bEIEJ2a… 1/3 11/7/23, 2:11 PM Realizeit for Student dangerous elevation of body temperature, all related to the increase in metabolism. Beta-blockers are used to control these symptoms. Thyroid hormone replacement is started 4 to 18 weeks after the antithyroid medications have been stopped based on the results of thyroid function tests. TSH measurements can be misleading in the early months following treatment with radioactive iodine. Therefore, serum free T4 is the principal test measured at 3 to 6 weeks following administration of radioactive iodine and then every 1 to 2 months until normal thyroid function is established. If TSH and free T4 are both persistently low, the total T3 then must be measured to differentiate between persistent hyperthyroidism (T3 elevated) or transient hypothyroidism (T3 normal or low). Once a normal thyroid state has been established, TSH should be measured every 6 to 12 months for life (Fischbach & Fischbach, 2018). A major advantage of treatment with radioactive iodine is that it avoids many of the side effects associated with antithyroid medications. However, some patients may elect to be treated with antithyroid medications rather than radioactive iodine for a variety of reasons, including fear of radiation. Patients who receive radioactive iodine should be informed that they can contaminate their household and other people through saliva, urine, or radiation emitting from their body. They should avoid sexual contact, sleeping in the same bed with other people, having close contact with children and pregnant women, and sharing utensils and cups. The patient should follow the instructions provided regarding the time restrictions for these cautions because they are dose related (Fischbach & Fischbach, 2018). Adjunctive Therapy Additional medications may be necessary. Potassium iodide (SSKI) may be used in combination with antithyroid agents or beta-adrenergic blockers to prepare the patient with hyperthyroidism for surgery. The drugs reduce the effects of hyperthyroidism quickly and help to prevent the onset of thyroid storm. The usual dosage for SSKI is 5 drops every 6 hours. The usual dose of propylthiouracil https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZMyySaAjt8dTx3FnIrt15HOKniKu5nqplgCFS7%2bEIEJ2a… 2/3 11/7/23, 2:11 PM Realizeit for Student is 200 mg every 6 hours and the usual dose of propranolol is 60 to 80 mg orally every 6 hours to prevent tachycardia. The patient will need to continue to take the propylthiouracil and any cardiac medication until the free T4 and T3 levels are near normal (Bauerle & Clutter, 2019). https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZMyySaAjt8dTx3FnIrt15HOKniKu5nqplgCFS7%2bEIEJ2a… 3/3