What is the best diagnostic approach and treatment for hyperthyroidism?

From the Guidelines

The best scan to evaluate hyperthyroidism is a thyroid ultrasound, as it can confirm the presence of nodules and evaluate for suspicious features of malignancy, and can be used in conjunction with a radioactive iodine uptake scan to determine the cause of hyperthyroidism. According to the American College of Radiology 1, ultrasound (US) is the best imaging study to evaluate thyroid morphology and can be a helpful adjunct study to a radioiodine uptake. US can confirm the presence of nodules and evaluate for suspicious features of malignancy, and can also provide thyroid dimensions for planning radioactive iodine (RAI) treatment.

Some key points to consider when evaluating hyperthyroidism include:

• Measuring thyroid-stimulating hormone (TSH) and free thyroid hormones (T4 and T3) to confirm hyperthyroidism
• Using thyroid antibodies (TSI or TRAb) to diagnose Graves' disease
• Utilizing a radioactive iodine uptake scan to determine the cause of hyperthyroidism
• Considering thyroid ultrasound to evaluate thyroid morphology and confirm the presence of nodules
• Evaluating for suspicious features of malignancy using ultrasound

It's also important to note that treatment for hyperthyroidism depends on the cause, patient age, and comorbidities, and may include antithyroid medications, radioactive iodine ablation, or thyroidectomy. Regular monitoring of thyroid function is essential during treatment, with liver function and complete blood count monitoring for patients on antithyroid drugs due to potential side effects. Patients should be educated about symptoms of agranulocytosis (fever, sore throat) which requires immediate medical attention. Treatment duration with antithyroid drugs is typically 12-18 months for Graves' disease, with approximately 30-50% achieving remission.

From the FDA Drug Label

Thyroid function tests should be monitored periodically during therapy The best diagnostic approach for hyperthyroidism is to monitor thyroid function tests periodically during therapy.

• Thyroid function tests are the primary method for evaluating hyperthyroidism. There is no information about the best scan to evaluate hyperthyroidism in the provided drug labels 2 2.

From the Research

Diagnostic Approaches for Hyperthyroidism

• The radioactive iodine uptake test and thyroid scintiscanning are used to identify the cause of hyperthyroidism and aid in the selection of the I-131 dose in treatment 3.
• Thyroid scintiscanning is used to identify normal and ectopic thyroid tissue, diagnose the cause of hyperthyroidism, and evaluate selected patients with thyroid nodules 3.
• Ultrasonography and radionuclide imaging using [99mTc]Pertechnetate or radioactive iodine isotopes are essential tools in the diagnostic workup of hyperthyroidism 4.
• Color duplex sonography and ultrasound elastography may add important information to find the cause of the hormone excess 4.
• Hybrid imaging using SPECT/-(CT) or PET-based methods, such as 124Iodine-PET/CT or 124Iodine-PET/ultrasound, may be used to localize ectopic thyroid tissue or in multinodular goiter 4.

Treatment of Hyperthyroidism

• Radioactive iodine treatment can be effective in eliminating hyperthyroidism due to Graves' disease, with a success rate of over 90% 5.
• The goal of radioactive iodine treatment is to achieve hypothyroidism within 3-6 months of administration 5.
• Ablative approaches using radioiodine are increasingly proposed for the treatment of Graves' disease, but their ophthalmologic and biological autoimmune responses remain controversial 6.
• Radioiodine thyroid ablation can be effective in eradicating Graves' hyperthyroidism, but may be accompanied by Graves' ophthalmopathy occurrence, particularly in patients with early hypothyroidism and high pretreatment TSH-receptor antibodies 6.

Special Considerations

• Subacute thyroiditis, ectopic hyperthyroidism, and iodine-induced hyperthyroidism may have low radioactive iodine uptake and require different diagnostic and treatment approaches 7.
• Amiodarone-associated hyperthyroidism may be challenging to assess and treat, and [99mTc]MIBI imaging may be useful in this context 4.