Division of Endocrinology, Clínica Stella Maris, Lima, Peru.
Division of Endocrinology, Hospital Nacional Guillermo Almenara Irigoyen, Lima, Peru.
Endokrynol Pol. 2021;72(6):650-660. doi: 10.5603/EP.a2021.0093. Epub 2021 Dec 2.
Hypothyroidism is an endocrine disorder whose management raises many challenges in clinical practice. Its standard treatment is levothyroxine (LT4). The goal of the treatment is to normalize signs and symptoms, as well as to achieve thyroid-stimulating hormone (TSH) concentrations within the reference range, on an individual basis. It is known that 5-10% of hypothyroid patients remain symptomatic, despite achieving the target TSH levels, which, in turn, affects their quality of life. After ruling out other causes of non-thyroid origin for this persistence, it is suggested that these patients could benefit from the use of liothyronine (LT3), added to LT4, especially if polymorphism of the deiodinase 2 (D2) genes is documented. There exist a variety of LT3 preparations, whose concentrations vary from 5 to 50 ug, with the recommended LT4/LT3 ratio of 13:1-20:1. The goals of combination therapy should be to achieve a physiological ratio of free triiodothyronine/free thyroxine (FT3/FT4) and non-suppression of TSH. Because there is currently no guide that makes evidence-based recommendations on the use of LT3 in primary hypothyroidism, more clinical studies are needed to be able to identify hypothyroid patients who may benefit from the use of LT3, by identifying new biomarkers.
甲状腺功能减退症是一种内分泌紊乱，其管理在临床实践中带来了许多挑战。其标准治疗方法是左甲状腺素（LT4）。治疗的目标是根据个体情况，使体征和症状正常化，并使促甲状腺激素（TSH）浓度达到参考范围内。已知，尽管达到了目标 TSH 水平，但 5-10%的甲状腺功能减退症患者仍有症状，这反过来又影响了他们的生活质量。在排除了这种持续存在的非甲状腺来源的其他原因后，建议这些患者可以从使用左甲状腺素（LT3）中受益，LT3 可与 LT4 联合使用，特别是如果记录了脱碘酶 2（D2）基因的多态性。存在各种 LT3 制剂，其浓度从 5 到 50ug 不等，推荐的 LT4/LT3 比例为 13:1-20:1。联合治疗的目标应该是实现游离三碘甲状腺原氨酸/游离甲状腺素（FT3/FT4）的生理比例和 TSH 不被抑制。因为目前没有关于在原发性甲状腺功能减退症中使用 LT3 的指南，因此需要更多的临床研究来确定可能受益于 LT3 治疗的甲状腺功能减退症患者，通过识别新的生物标志物。
