What is the appropriate workup and treatment for hyperthyroidism (excessive thyroid hormone production)?

From the Guidelines

Hyperthyroidism workup begins with thyroid function tests, specifically TSH (typically suppressed) and free T4/T3 (typically elevated), and treatment depends on the cause, severity, and patient factors, with antithyroid medications, radioactive iodine ablation, or thyroidectomy being potential options, as recommended by the most recent guidelines 1.

Key Considerations

• The primary screening test for thyroid dysfunction is the serum TSH test, with multiple tests done over a 3- to 6-month interval to confirm or rule out abnormal findings 1.
• Treatment for hyperthyroidism is generally recommended for patients with a TSH level that is undetectable or less than 0.1 mIU/L, particularly those with overt Graves disease or nodular thyroid disease 1.
• Beta-blockers, such as propranolol, can help control sympathetic symptoms in patients with hyperthyroidism, including those with thyrotoxicosis or symptomatic hyperthyroidism 1.
• Thyroid storm requires aggressive management with high-dose antithyroid drugs, beta-blockers, corticosteroids, and supportive care, with treatment not delayed for test results 1.

Treatment Options

• Antithyroid medications, such as methimazole or propylthiouracil, are first-line treatments for Graves' disease, with beta-blockers used to control sympathetic symptoms.
• Radioactive iodine ablation or thyroidectomy are definitive treatment options for Graves' disease and toxic nodular disease.
• Patients on antithyroid medications require monitoring for side effects, including agranulocytosis, hepatotoxicity, and rash, with regular thyroid function tests performed every 4-6 weeks initially, then every 3 months once stable.

From the FDA Drug Label

Propylthiouracil inhibits the synthesis of thyroid hormones and thus is effective in the treatment of hyperthyroidism. The appropriate treatment for hyperthyroidism includes the use of propylthiouracil, which inhibits the synthesis of thyroid hormones.

• The drug is effective in treating hyperthyroidism by inhibiting the synthesis of thyroid hormones.
• It does not inactivate existing thyroxine and triiodothyronine.
• Propylthiouracil may also be effective in treating thyroid storm by inhibiting the conversion of thyroxine to triiodothyronine in peripheral tissues. However, the FDA drug label does not provide information on the appropriate workup for hyperthyroidism. 2

From the Research

Diagnosis of Hyperthyroidism

• Hyperthyroidism is a condition where the thyroid gland produces and secretes inappropriately high amounts of thyroid hormone, which can lead to thyrotoxicosis 3.
• The diagnosis can be made based on clinical findings and confirmed with biochemical tests and imaging techniques, including ultrasound and radioactive iodine uptake scans 3.
• Overt hyperthyroidism is defined as a low or undetectable thyrotropin (TSH) level with elevated triiodothyronine (T3) or thyroxine (T4) values, whereas subclinical hyperthyroidism is defined as low or undetectable TSH with normal T3 and T4 levels 4.

Treatment Options for Hyperthyroidism

• Management options for hyperthyroidism include anti-thyroid medications, radioactive iodine, and surgery 3.
• Anti-thyroid medications, such as methimazole (MMI) and propylthiouracil (PTU), are used to inhibit the synthesis of thyroid hormone and can be used as the primary treatment for hyperthyroidism or as a preparation before radioiodine therapy or thyroidectomy 5.
• Radioactive iodine is a successful treatment for hyperthyroidism, but should not be used in Graves' disease with ophthalmic manifestations 3, 6.
• Surgery, including total thyroidectomy or thyroid lobectomy, is considered for those who have a concurrent cancer, are pregnant, have compressive symptoms, or have Graves' disease with ophthalmic manifestations 3, 6.

Considerations for Treatment

• The choice of treatment depends on the underlying diagnosis, the presence of contraindications to a particular treatment modality, the severity of hyperthyroidism, and the patient's preference 7.
• Patients with subclinical hyperthyroidism may not always require treatment, but close monitoring is needed to prevent disease complications or progression to overt hyperthyroidism 4.
• Treatment for subclinical hyperthyroidism is recommended for patients 65 years or older with TSH levels lower than 0.10 mIU/L, symptomatic patients, or those with cardiac or osteoporotic risk factors 4.

Cardiovascular Considerations

• Hyperthyroidism can impact the cardiovascular system, and common manifestations include hypertension and tachycardia 3.
• Early treatment of cardiovascular manifestations, along with treatment of the hyperthyroidism, can prevent significant cardiovascular events 3.
• Beta blockers can be used to treat cardiovascular manifestations, such as tachycardia and hypertension 3.