Wiebel J, Kuhn N, Stahnke N, Willig R P
Monatsschr Kinderheilkd (1902). 1976 Sep;129(9):667-72.
According to more recent knowledge L-thyroxine alone is recommended for thyroid hormone replacement therapy, no longer the combination of L-thyroxine and triiodothyronin, since L-thyroxine is converted to triiodothyronine in the periphery of the body. Additional application of triiodothyronine causes unphysiological elevations of blood levels of triiodothyronine. When changing from the combined thyroid hormone therapy to treatment with L-thyroxine alone it is enough in most cases to replace the previous amount of L-thyroxine only; previous recommendations for the dosage of thyroid hormone were rather high. Average requirements of adults for L-thyroxine are around 170 mug per day. Children need about 90--100 mug per m2 body surface per day. -- When hypothyroidism is suspected in newborns or infants no protracted diagnostic procedures are justified with respect to brain development and its requirement of thyroid hormone during this period of life. Replacement therapy should be started within 1--2 days. The exact diagnosis can be established later, for instance during the third day of life when a temporary interuption of treatment for diagnostic purposes has no longer such negative effect on normal brain development. As long as physiological doses of L-thyroxine are used no side effects are to be expected for patients who later turn out to be euthyroid. -- Following exclusion of hyperthyroidism goitres in children and adolescents equally need thyroid hormone replacement therapy to reduce the size or prevent further enlargement or even the development of nodules within the gland. The dosage for this is about half to three quarters of the full replacement dose. The nature of thyroid nodules should be investigated, even surgically, since malignancies can develop in children and juveniles as well as in adults.
根据最新的认识，甲状腺激素替代疗法仅推荐使用左甲状腺素，不再使用左甲状腺素与三碘甲状腺原氨酸的组合，因为左甲状腺素在人体外周会转化为三碘甲状腺原氨酸。额外使用三碘甲状腺原氨酸会导致血液中三碘甲状腺原氨酸水平出现非生理性升高。从联合甲状腺激素疗法改为仅用左甲状腺素治疗时，在大多数情况下，仅替换先前左甲状腺素的用量就足够了；先前关于甲状腺激素剂量的建议相当高。成年人对左甲状腺素的平均需求量约为每天170微克。儿童每天每平方米体表面积需要约90 - 100微克。——当怀疑新生儿或婴儿患有甲状腺功能减退时，考虑到这一时期大脑发育及其对甲状腺激素的需求，不应进行冗长的诊断程序。替代疗法应在1 - 2天内开始。确切诊断可稍后确定，例如在出生后第三天进行，此时为诊断目的暂时中断治疗对正常大脑发育不再有如此负面的影响。只要使用生理剂量的左甲状腺素，对于后来被证明甲状腺功能正常的患者，预计不会有副作用。——在排除甲状腺功能亢进后，儿童和青少年的甲状腺肿同样需要甲状腺激素替代疗法，以缩小甲状腺大小或防止其进一步增大，甚至防止腺体内出现结节。其剂量约为完全替代剂量的一半至四分之三。应调查甲状腺结节的性质，甚至进行手术，因为儿童、青少年以及成年人都可能发生恶性肿瘤。
