What preparation is required before a patient undergoes a subtotal thyroidectomy?

A patient undergoing a subtotal thyroidectomy may require specific treatment in preparation for the operation to decrease the risk of potential complications. This treatment may vary, depending on whether the operation is an elective procedure scheduled in advance, or an urgent procedure that must be performed in the setting of severe or life-threatening hyperthyroidism.

Patients undergoing elective procedures are usually started on treatment with an antithyroid drug several weeks before a planned operation. Treatment with an antithyroid drug helps to block the production of new molecules of thyroid hormone, decreasing the total amount of thyroid hormone present in the thyroid gland. This may help to decrease the risk of releasing a large amount of thyroid hormone into the bloodstream during the course of surgery. Patients undergoing elective procedures may also be treated with an agent called potassium iodide starting approximately two weeks before a planned operation. Potassium iodide acts to shrink blood vessels in the thyroid gland that may grow and expand with progressive enlargement in the setting of Graves’ disease. This may help to decrease the amount of bleeding that occurs when thyroid tissue is removed during the course of surgery. Potassium iodide also works to block the secretion of thyroid hormone from the thyroid gland. It is usually administered as a liquid in the form of a preparation called saturated solution of potassium iodide. Drops of this preparation are usually taken three times a day in a glass of juice.

Patients undergoing urgent procedures are usually started on treatment with high doses of a beta blocker, a glucocorticoid, and an iodinated contrast agent. These medications work together to block the conversion of T4 to T3. This may help to decrease the risk associated with exposure to excess amounts of the more active form of thyroid hormone.