碘缺乏病病区经食盐加碘后甲状腺功能亢进患病率升高的病因分析

目的 探讨在碘缺乏病(IDD)病区经碘盐防治后，甲状腺功能亢进(甲亢)患病率升高的原因及其可能的发病机制。方法 对来自于海陆丰地区(IDD高发区)的甲状腺疾病患者的临床资料进行统计分析，其中包括58例地方性结节型甲状腺肿患者和经^131I治疗的255例甲亢患者。结果 该地区甲亢患者绝大多数是在5年以上患有地方性结节型甲状腺肿的基础上发生的。未合并甲亢的地方性结节型甲状腺肿患者的甲状腺功能、血清甲状腺激素水平及甲状腺过氧化物酶抗体(TPOAb)水平均正常；而合并甲亢者血清甲状腺激素和TPOAb水平明显升高，经^131I治疗后，甲状腺功能恢复正常，但血清TPOAb仍维持高水平。结论 在IDD病区推行碘盐后．甲亢患病率增加的原因是部分原有的地方性结节型甲状腺肿患者在补碘后诱发了甲亢。其可能的发病机制是这部分患者存在甲状腺自身免疫缺陷。

Study of pathogenesis of increasing incidence of hyperthyroidism after administration of iodized salt in iodine deficiency disorders region

Objective To study etiology and possible mechanism of increasing incidence of hyperthyroidism after administration of salt iodization in iodine deficiency disorders(IDD) region.Methods Fifty eight patients with endemic multinodular goiter (EMG) and 255 with hyperthyroidism receiving 131 I therapy referred from two known IDD regions (Haifeng and Lufeng) underwent SPECT scans and serum test in our department. All images and laboratory data were analyzed.Results The statistical results of analysis showed the majority of hyperthyroidism ensued from EMG with a 5 (or more)-year history. Compared with the normal thyroid function, serum thyroid hormone (FT 3, FT 4) and titer of TPOAb in EMG patients without hyperthyroidism, the serum levels of thyroid hormone and TPOAb increased significantly in EMG patients with hyperthyroidism, even after 131 I therapy.Conclusions The increasing incidence of hyperthyroidism in IDD regions after salt iodization can be attributed to the occurrence of iodine-induced hyperthyroidism in some EMG patients and the autoimmune deficiency may be the possible pathogenesis.