What is the best management for a pregnant patient with symptoms suggestive of hyperthyroidism (excessive thyroid hormone production) and a thyroid scan showing diffuse uptake along with a cold nodule?

From the Guidelines

The best management for a pregnant patient with symptoms of hyperthyroidism and a thyroid scan showing diffuse uptake with a cold nodule is to immediately discontinue the thyroid scan and initiate propylthiouracil (PTU) during the first trimester, switching to methimazole for the second and third trimesters. This approach is based on the most recent and highest quality evidence available, which prioritizes minimizing risks to the developing fetus while treating maternal hyperthyroidism 1.

Key Considerations

• Thyroid scans using radioactive iodine are contraindicated during pregnancy as they can damage the fetal thyroid gland.
• PTU is preferred initially because methimazole has a slightly higher risk of rare congenital abnormalities in the first trimester.
• The cold nodule should be evaluated with ultrasound and fine needle aspiration if indicated, as it may represent thyroid cancer.
• Beta-blockers like propranolol can be used briefly for symptom control.
• The goal is to maintain maternal free T4 in the upper normal range with the lowest possible antithyroid drug dose.

Management and Monitoring

• Monthly thyroid function monitoring is essential.
• An obstetric specialist should be involved in care.
• This approach balances treating maternal hyperthyroidism while minimizing risks to the developing fetus, as untreated hyperthyroidism can lead to pregnancy complications including miscarriage, preeclampsia, and fetal growth restriction 1.

Treatment Options

• Propylthiouracil (PTU) during the first trimester, switching to methimazole for the second and third trimesters.
• Beta-blockers like propranolol for brief symptom control.
• Evaluation and potential treatment of the cold nodule.

This management strategy prioritizes the health and well-being of both the mother and the fetus, minimizing the risks associated with hyperthyroidism and its treatment during pregnancy.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Management of Hyperthyroidism in Pregnancy

The management of hyperthyroidism in a pregnant patient involves several considerations to ensure favorable maternal and fetal outcomes.

• The patient's symptoms, such as tremors and palpitations, and the presence of a diffuse thyromegaly and a cold nodule, suggest hyperthyroidism.
• The thyroid scan showing diffuse uptake by the gland is consistent with Graves' disease, a common cause of hyperthyroidism in pregnancy 2.
• The presence of a cold nodule requires further evaluation, but it is not typically an indication for immediate surgery.

Treatment Options

The treatment options for hyperthyroidism in pregnancy include:

• Antithyroid drugs, such as propylthiouracil (PTU) or methimazole (MMI), which are the main therapeutic form administered in pregnant women 2, 3, 4.
• Radioactive iodine therapy is contraindicated during pregnancy due to the risk of fetal thyroid damage 2.
• Thyroidectomy may be considered in severe cases of hyperthyroidism that are unresponsive to medical therapy, but it is not typically the first line of treatment 2.
• External beam radiation is not a recommended treatment for hyperthyroidism in pregnancy.

Best Management

Based on the available evidence, the best management for this patient would be to start antithyroid drugs, such as PTU, to control the hyperthyroidism, and to monitor the patient's thyroid function and adjust the treatment as needed 2, 3, 4, 5.

• The cold nodule should be evaluated further, but it is not typically an indication for immediate surgery.
• The patient should be monitored closely for any adverse effects of the antithyroid drugs, such as liver damage or agranulocytosis 3, 4.