先天性甲状腺功能低下症儿童服药及停药后观察时限的研究

目的:探讨先天性甲状腺功能低下症(CH)儿童治疗服药及停药所需观察时限,为安全停药提供客观依据。方法:对确诊的1 144例CH患儿予以左旋甲状腺素钠治疗,定期复查体格发育及智力发育,甲状腺B超,血T 3、T 4、TSH。左旋甲状腺素钠维持剂量较小(15.0~16.6μg/d)且所有指标持续正常者在2~3岁后试停药,并在停药后1个月、2个月、10个月时随访复查。仍维持正常的儿童予以永久停药;若在停药观察期间患儿血TSH出现异常则视具体情况给予重新服药或继续观察。结果:157例停药观察儿童经随访重新服药15例(9.55%),最终停药142例(确诊为暂时性CH)。本组共有48例患儿在随访期间血TSH出现不同程度的异常。在停药1个月后出现异常有40例(25.48%),在2个月时出现异常的有7例(4.46%),仅1例在10个月后始出现异常。结论:在经甲状腺素药物规范治疗2~3年后,较小剂量的药物仍能维持血T 3、T 4、TSH正常,生长发育和甲状腺检查均无异常的CH儿童应停药观察。停药观察时限应为2~3个月,若血T 3、T 4、TSH仍处于正常范围,则可安全停药。在随访中若出现明显的异常则应继续药物治疗。

Observation time for drug administration and withdrawal in the treatment of children with congenital hypothyroidism

OBJECTIVE: To study the best observation time for drug administration and withdrawal in the treatment of children with transient congenital hypothyroidism,seeking an objective basis for the safe drug withdrawal. METHODS: Levothyroxine was prescribed for 1 144 children diagnosed with congenital hypothyroidism (CH) and according to the results levothyroxine was adjusted to a maintenance dosage. Examinations were performed periodically including physical and mental development, thyroid ultrasonography,and blood levels of T3, T4, TSH. For the patients with a small maintenance dosage of levothyroxine (15.0 - 16.6 g/d) and all the examinations normal, levothyroxine was withdrawn at 2 - 3 years, and the children were followed up and reexamined after 1 month, 2 months, and 10 months, respectively. Permanent drug withdrawal was determined for children with all the examinations normal. Once abnormal TSH occurred, levothyroxine was prescribed again, and followed up continuously. RESULT: Levothyroxine was withdrawn from 157 children. During the follow up, for 15 children (9.55%) levothyroxine were prescribed continuously, and for 142 children permanent drug withdrawal (confirmed with transient CH) was determined. Abnormal TSH of various degrees was detected in 48 cases: 25.48 % (40/157),4.46 % (7/157), and 0.64 % (1/157) were detected at 1, 2 and 10 months after drug withdrawal, respectively. In 15 children levothyroxine was prescribed again for the remarkably high TSH, and the other 33 with mildly abnormal TSH finished the treatment since TSH normalized during follow-up. CONCLUSION: After 2 - 3 years of regular treatment, levothyroxine can be withdrawn from children with normal T3, T4, TSH, physical and mental development, and thyroid function. The best observation time for drug withdrawal should be 2 - 3 months. If T3, T4 and TSH levels are in the normal range, drug can be withdrawn safely. Once abnormal results were detected during follow-up, levothyroxine should be administrated continuously.