Preoperative Preparation in Hyperthyroidism and Surgery in the Hyperthyroid State.

Abstract

Hyperthyroidism is a clinical condition that develops due to the excessive production and secretion of thyroid hormones by the thyroid gland, leading to an elevated concentration of thyroid hormones in tissues. Hyperthyroidism is characterized by low TSH and elevated T3 and/or T4, with the most common causes being Graves' disease, toxic multinodular goiter, and solitary toxic adenoma. T3 is the peripherally active form of thyroid hormone, affecting nearly each tissue and system. The most prominent aspects of hyperthyroidism are related to the cardiovascular system. The treatment of hyperthyroidism includes three options: antithyroid drugs (ATDs), radioactive iodine therapy (RAI), and surgery. Among these treatment modalities, surgery is considered as the most effective one. For patients who are candidates for surgery, preoperative preparation is required to ensure that the thyroidectomy can be performed under optimal conditions. Preoperative preparation should be a combination therapy aimed at preventing the synthesis, secretion, and peripheral effects of thyroid hormones from the thyroid gland. Medications that can be used in this treatment include thionamides, beta-blockers, iodine, corticosteroids, cholestyramine, perchlorate, lithium, and therapeutic plasma exchange. These treatment options can be combined based on the patient's condition. While it is recommended that patients be made euthyroid through preoperative antithyroid treatment to prevent the feared complication, which is the thyroid storm, the supporting evidence is limited. Preoperative treatment does not prevent against thyroid storm whether the patient is euthyroid or hyperthyroid during surgery. Whether surgery should be delayed until biochemical euthyroidism is achieved in hyperthyroid patients remains a topic of debate. Recent studies suggest that thyroidectomy can be safely performed during the hyperthyroid phase by experienced anesthesiologists and surgeons without precipitating thyroid storm or increasing intraoperative and postoperative complications. Although achieving the euthyroid state before surgery is ideal in hyperthyroid patients, it is not always possible. Factors such as allergies to medications, drug side effects, treatment-resistant disease, patient noncompliance, and the urgency of definitive treatment are critical in determining whether hyperthyroidism can be controlled preoperatively. When surgery is necessary in hyperthyroid patients without achieving euthyroidism, the patient's overall condition and comorbidities should be evaluated together by the anesthesiologist, surgeon and endocrinologist, with particular attention to stabilizing the cardiovascular system. We believe that in hyperthyroid patients who are cardiovascularly stable during the hyperthyroid phase, thyroid surgery may not need to be delayed and can be performed safely.