The Change of Thyroid Hormone by Short-term Antithyroid Drug Treatment for Preoperative Euthyroidism in TSH-secreting Pituitary Adenoma

Abstract

Preoperative euthyroidism is needed to minimize the risk of intraoperative and postoperative complications, such as thyroid storm by surgery. Antithyroid drugs or steroid hormones are commonly used in primary hyperthyroidism for euthyroidism. However, there is no definite consensus for the preoperative management of a TSH secreting pituitary adenoma for the restoration of euthyroidism. Antithyroid drugs are not used for long-term the management of a TSH secreting pituitary adenoma, as they may cause rapid growth and greater invasiveness of the tumor due to a feedback mechanism, but they can be used for short-term management before neurosurgery. We experienced one case of a TSH secreting pituitary adenoma, which showed rapid free thyroid hormone increase due to the short term administration of antithyroid drugs for only 10 days. A somatostatin analogue, octreotide at a dose of 0.1 mg, twice a day, was then tried. About 4 weeks later, her serum TSH and free T4 had normalized, with a concomitant clinical improvement. She subsequently underwent an uncomplicated trans-sphenoidal resection of the pituitary adenoma. Antithyroid drugs can induce a rapid thyroid hormone increase, but can only be used for a short-term period, so they should be administered with caution or their use reconsidered (J Kor Soc Endocrinol 20:261～267, 2005).