Can a patient with biochemical hyperthyroidism who is clinically euthyroid undergo a thyroidectomy (thyroid removal surgery)?

From the Guidelines

A patient with biochemical hyperthyroidism who is clinically euthyroid can proceed with thyroidectomy, but preoperative optimization is crucial to minimize risks. The patient should be treated with beta-blockers, such as propranolol 20-40mg three times daily or atenolol 25-50mg once daily, starting 1-2 weeks before surgery to prevent perioperative thyroid storm, as recommended by the U.S. Preventive Services Task Force 1. Additionally, consider adding antithyroid medications like methimazole (10-30mg daily) or propylthiouracil (100-300mg daily in divided doses) if the biochemical hyperthyroidism is significant (free T4 >50% above normal range). Preoperative iodine preparation with Lugol's solution (3-5 drops three times daily) for 7-10 days before surgery can reduce thyroid vascularity and decrease surgical bleeding. It is essential to ensure the patient has recent thyroid function tests (within 4 weeks), a normal ECG, and adequate hydration before proceeding, as the treatment of thyroid dysfunction has not been well-studied, and the harms of treatment, including false-positive results, labeling, and overdiagnosis and overtreatment, should be considered 1. The anesthesiologist should be informed about the patient's thyroid status to prepare for potential hemodynamic instability. This approach is necessary because even biochemical hyperthyroidism without clinical symptoms carries risks during surgery, including increased risk of arrhythmias, hemodynamic instability, and thyroid storm under the stress of surgery and anesthesia.

Some key considerations for the preoperative optimization include:

• Recent thyroid function tests (within 4 weeks) to assess the severity of biochemical hyperthyroidism
• Normal ECG to evaluate cardiac function and potential risks
• Adequate hydration to prevent complications during surgery
• Informing the anesthesiologist about the patient's thyroid status to prepare for potential hemodynamic instability
• Using beta-blockers and antithyroid medications as needed to minimize risks during surgery, as the effects of treatment of thyroid dysfunction on important clinical outcomes may be independent of any known intermediate outcomes 1.

The primary goal of preoperative optimization is to minimize the risks associated with thyroidectomy in patients with biochemical hyperthyroidism, while also considering the potential harms of treatment, including false-positive results, labeling, and overdiagnosis and overtreatment 1.

From the FDA Drug Label

In patients with Graves’ disease with hyperthyroidism or toxic multinodular goiter for whom surgery or radioactive iodine therapy is not an appropriate treatment option. To ameliorate symptoms of hyperthyroidism in preparation for thyroidectomy or radioactive iodine therapy. The patient has biochemical hyperthyroidism and is clinically euthyroid, which suggests that the hyperthyroidism is being managed.

• Thyroidectomy can proceed as methimazole is used to ameliorate symptoms of hyperthyroidism in preparation for thyroidectomy 2.
• The fact that the patient is clinically euthyroid indicates that the hyperthyroidism is being adequately controlled, making it possible to proceed with the surgery.

From the Research

Thyroidectomy for Biochemically Hyperthyroid Patients

• The decision to proceed with thyroidectomy for a patient with biochemical hyperthyroidism who is clinically euthyroid can be made based on several factors, including the severity of hyperthyroidism and the patient's overall health status 3, 4.
• Studies have shown that thyroidectomy can be safely performed in patients with mild to moderate biochemical hyperthyroidism, with no significant increase in adverse outcomes 3, 4.
• However, it is still recommended to attempt to achieve a euthyroid state whenever possible prior to thyroid surgery, as this can reduce the risk of complications and improve outcomes 3, 5.

Management of Hyperthyroidism

• Hyperthyroidism can be managed with anti-thyroid medications, radioactive iodine, or surgery, depending on the underlying cause and severity of the condition 5, 6.
• Anti-thyroid medications, such as methimazole and propylthiouracil, can be used to inhibit the synthesis of thyroid hormone and are often used as the primary treatment for hyperthyroidism or as a preparation before radioiodine therapy or thyroidectomy 7.
• Beta blockers can be used to manage cardiovascular manifestations of hyperthyroidism, such as hypertension and tachycardia 5.

Surgical Treatment of Hyperthyroidism

• Thyroidectomy is a safe and effective treatment for hyperthyroidism, and can be performed in patients with uncontrolled hyperthyroidism without increasing the risk of thyroid storm 4.
• The choice of surgical treatment depends on the underlying diagnosis, the presence of contraindications to a particular treatment modality, and the patient's preference 6.
• Surgery can be considered for patients who have a concurrent cancer, are pregnant, have compressive symptoms, or have Graves' disease with ophthalmic manifestations 5.