甲状腺功能减退症的诊治

Diagnosis and management of hypothyroidism

摘要:

甲状腺功能减退症（甲减）是由多种原因引起的甲状腺激素合成、分泌或生物效应不足所致的一种全身代谢减低综合征。原发性甲减是其中最常见的类型，主要由自身免疫甲状腺炎如桥本病所致，其他原因包括由于中枢促甲状腺激素释放激素（TRH）或促甲状腺激素（TSH）不足、甲状腺手术或放射性碘治疗导致的甲减。甲状腺激素的测定，包括TSH和游离甲状腺素（FT4）等，是甲减诊断的主要手段。甲减的诊断可分为临床（TSH高，FT4低）或亚临床甲减（TSH高，FT4正常）。甲减治疗的目的是纠正甲状腺功能不足，减轻症状，避免进展至粘液性水肿。甲减通常采用合成的左甲状腺素治疗。尽管典型甲减的诊断、治疗在临床上较为简单，但有相当部分患者治疗并未达到最优化，即使甲状腺功能指标正常仍感觉生活质量较差。本文简述了甲减的病因、分类、诊断和治疗。对部分患者治疗效果不佳的可能原因及优化措施亦进行了讨论。

Abstract:

Hypothyroidism is a systemic metabolic disorder resulting from inadequate production of thyroid hormone (TH) or inadequate action of TH to target tissues. Primary hypothyroidism, as the principal type, is mainly caused by Hashimoto￠s thyroiditis, while, other causes include central deficiency of thyrotropin-releasing hormone or thyroid-stimulating hormone (TSH), or the outcome after the thyroid surgery or radioiodine therapy for hyperthyroidism. It is difficult to diagnose thyroid diseases based only on symptoms, but manifestation of these symptoms could be an indicator for thyroid function evaluation. Evaluations of TSH and free thyroxine (FT4) is used to diagnose overt hypothyroidism (high TSH with low FT4 levels) and subclinical hypothyroidism (high TSH with normal FT4 levels). The goal to treat hypothyroidism is to relieve symptoms and avoid progression to myxedema. Hypothyroidism is usually treated with synthetic levothyroxine. Although the diagnosis and treatment of hypothyroidism is often considered simple, there are large numbers of people with hypothyroidism who are suboptimally treated. Even in those people with biochemically euthyroid on levothyroxine replacement, there is a significant proportion who report poorer quality of life. This review summarized etiology and types of hypothyroidism, including subclinical disease, and diagnosis and current treatment for hypothyroidism. The reasons for suboptimal treatment and potential solutions were also discussed.