75例极低出生体重儿甲状腺激素检测及其临床意义

Measurement and clinical relevance of blood thyroid hormones:an analysis in 75 cases of very low birth weight infants.

目的:探讨极低出生体重儿甲状腺激素的变化和临床意义。方法:选择2009年11月到2010年12月间入住本院新生儿重症监护室病区,共75例极低出生体重儿,按出生体重分为500-1000g、1001-1500g两组,对照组30例为健康足月新生儿。生后3～7天测定血甲状腺激素FT_3、FT_4、TSH水平,异常者7～10 d后复查,记录典型甲状腺功能低下临床表现发生率。对连续2次FT_3、FT_4低下者予以小剂量口服左甲状腺素。结果:体重500-1000g组、1001-1500 g组的FT_3、FT_4水平低于对照组,体重越低者FT_3、FT_4水平越低。3组间TSH水平无统计学差异;甲状腺素水平异常波动比例达65/75(86.7%),但临床表现不典型;以单纯FT_3降低、FT_4和FT_4均降低、单纯FT_4降低为3种主要表现类型。64.6%(42/65)异常者2次复查恢复正常水平,接受甲状腺激素治疗者仅32.3%(21/65)。结论:极低出生体重儿易出现暂时性甲状腺激素水平异常,多数可自行恢复,少数异常者需小剂量甲状腺素治疗。

Objective：To investigate the alterations and clinical relevance of blood thyroid hormone in very low birth weight （VLBW） infants. Methods ：75 very low birth weight（VLBW） infants who stayed in our neonatal intensive care unit （NICU） between November 2009 and December 2010 were enrolled and divided into （500 - 1000 ） g and （ 1001 - 1500 ） g groups according to their birth weight. Thirty healthy full-term newborns were set as controls. At 3 to 7 days after birth, the infants were evaluated for levels of blood thyroid hormones （ FT3 , FT4 and TSH）. Those with abnormal hormone levels underwent re-examination at 7 to 10 days later. Typical clinical manifestations of hypothyroidism were recorded, if any, in all groups. Low-dose oral levothyroxine were given to VLBW infants whose FT3 and/or FT4 levels were lower than normal in two consecutive tests. Results：The levels of FT3 and b-T4 in the two VLBW groups were lower than those in the control group. The levels of FT3 and FT4 seemed to decline along with lower birth weight. There was no significant difference in TSH level among the three groups. Abnormal fluctuation of thyroid hormone level was noted in 65 out of 75 （86.7%） cases,wherein the clinical manifestations of hypothroidism were atypical, and three major phenotypes were noted （simple FT3 deficiency, dual deficiency of FT3 and FT4, and simple FT4 deficiency）. 64.6% （42/65） VLBW infants with abnormal findings regained normal level of thyroid hormones at the second detection, and only 32.3% （21/65） received thyroid hormone replacement therapy. Conclusion： Transient abnormality in thyroid hormone level is more likely to occur in infants with very low birth weight. However, the majority can recover spontaneously, and only a small percentage of these infants need low-dose thyroid hormone replacement.