What is the initial workup and management of hyperthyroidism?

From the Guidelines

The initial workup of hyperthyroidism should include a comprehensive history and physical examination, followed by laboratory testing of thyroid function (TSH, free T4, and free T3) to confirm the diagnosis, as recommended by the most recent guidelines 1. The diagnosis of hyperthyroidism is typically made based on symptoms such as heat intolerance, tachycardia, anxiety, and weight loss, as well as laboratory tests showing low TSH levels and elevated free T4 and free T3 levels. Additional tests, such as thyroid antibodies (anti-TPO, TSI, TRAb), can help determine the etiology of hyperthyroidism, with Graves' disease being a common cause 1. Thyroid imaging, such as ultrasound or radioactive iodine uptake scan, can also be useful in assessing gland structure and function, particularly in cases where toxic adenoma or multinodular goiter is suspected 1. Management of hyperthyroidism typically begins with beta-blockers, such as propranolol (20-40mg every 6-8 hours) or atenolol (25-50mg daily), to control adrenergic symptoms. For definitive treatment, antithyroid medications, such as methimazole, are often preferred, with treatment continuing for 12-18 months and regular monitoring of thyroid function every 4-6 weeks initially, then every 2-3 months 1. Alternative definitive treatments, such as radioactive iodine ablation or thyroidectomy, may be considered for patients with large goiters, compressive symptoms, or those failing medical therapy, with the goal of restoring euthyroidism while minimizing complications. Some key points to consider in the management of hyperthyroidism include:

• The importance of regular monitoring of thyroid function to adjust treatment as needed
• The potential risks and benefits of different treatment options, including antithyroid medications, radioactive iodine ablation, and thyroidectomy
• The need to consider patient factors, such as age, pregnancy status, and comorbidities, when selecting a treatment approach
• The goal of restoring euthyroidism while minimizing complications and improving quality of life.

From the FDA Drug Label

Thyroid function tests should be monitored periodically during therapy Once clinical evidence of hyperthyroidism has resolved, the finding of a rising serum TSH indicates that a lower maintenance dose of methimazole should be employed.

The initial workup and management of hyperthyroidism involves monitoring thyroid function tests periodically during therapy.

• Thyroid function tests should be used to guide the adjustment of the maintenance dose of methimazole.
• A rising serum TSH indicates that a lower maintenance dose of methimazole should be employed 2. The provided drug labels do not explicitly outline the initial workup for hyperthyroidism, only the management with methimazole and the monitoring of thyroid function during therapy.

From the Research

Initial Workup of Hyperthyroidism

The initial workup of hyperthyroidism involves confirming the clinical suspicion with biochemical tests, including low TSH, high free thyroxine (FT4), or high free tri-iodothyonine (FT3) 3. Once hyperthyroidism is confirmed, a nosological diagnosis is necessary to determine the underlying cause of the condition.

Diagnostic Tools

Helpful tools for determining the cause of hyperthyroidism include:

• TSH-receptor antibodies
• Thyroid peroxidase antibodies
• Thyroid ultrasonography
• Scintigraphy 3, 4

Causes of Hyperthyroidism

Hyperthyroidism can be caused by:

• Graves' hyperthyroidism (70%)
• Toxic nodular goitre (16%)
• Subacute granulomatous thyroiditis (3%)
• Drugs (9%) such as amiodarone, tyrosine kinase inhibitors, and immune checkpoint inhibitors 3
• Thyroiditis, which can cause thyrotoxicosis without hyperthyroidism 4

Management of Hyperthyroidism

The management of hyperthyroidism depends on the underlying cause and may include:

• Antithyroid drugs, which are the preferred treatment for Graves' hyperthyroidism 3, 4
• Radioactive iodine ablation, which is commonly used for toxic nodular goitre and autonomous thyroid nodules 5, 6
• Thyroidectomy, which may be necessary for large goitres or nodules causing compressive symptoms 5, 6
• Supportive care for thyrotoxicosis caused by thyroiditis 5, 4

Special Considerations

Special attention is needed for patients with hyperthyroidism who are:

• Pregnant
• Have COVID-19
• Have other complications such as atrial fibrillation, thyrotoxic periodic paralysis, and thyroid storm 3