Benvenga Salvatore, Di Bari Flavia, Granese Roberta, Antonelli Alessandro
Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy.
Master Program on Childhood, Adolescent and Women's Endocrine Health, University of Messina, Messina, Italy.
Front Endocrinol (Lausanne). 2017 Sep 29;8:250. doi: 10.3389/fendo.2017.00250. eCollection 2017.
About one-fifth of patients treated with levothyroxine have serum thyrotropin (TSH) above target concentrations but, in approximately 15% of them, the cause of this TSH insufficient normalization remains unknown. We report the cases of two regularly menstruating women with known thyroid disease who had TSH levels consistently >3 mU/L (and sometimes above target levels) during mid-cycle, but consistently lower serum levels during the follicular and luteal phases of menstrual cycle. A major TSH release by the thyrotrophs in response to high circulating levels of estradiol (E2) at mid-cycle may increase levels of TSH compared to other phases of the cycle. The increased TSH can be misinterpreted as refractory hypothyroidism if the woman is under L-T4 replacement therapy or as subclinical hypothyroidism if the woman is not. Our findings might have important implications for diagnosis and management of thyroid disease, suggesting to request serum TSH measurements outside of the periovulatory days.
接受左甲状腺素治疗的患者中约五分之一的血清促甲状腺激素（TSH）高于目标浓度，但其中约15%的患者TSH未充分正常化的原因仍不明。我们报告了两名患有甲状腺疾病且月经规律的女性病例，她们在月经周期中期TSH水平持续>3 mU/L（有时高于目标水平），但在月经周期的卵泡期和黄体期血清水平持续较低。促甲状腺细胞在月经周期中期对高循环水平的雌二醇（E2）作出反应而大量释放TSH，这可能导致与月经周期其他阶段相比TSH水平升高。如果该女性接受左甲状腺素替代治疗，升高的TSH可能被误解为难治性甲状腺功能减退症；如果未接受治疗，则可能被误解为亚临床甲状腺功能减退症。我们的研究结果可能对甲状腺疾病的诊断和管理具有重要意义，建议在排卵期以外的时间进行血清TSH测量。
