Huang Chung-Bin, Chen Feng-Shun, Chung Mei-Yung
Pediatrics Department, Chang-Gung Children's Hospital, Kaohsiung, Taiwan.
Am J Perinatol. 2002 Apr;19(3):139-47. doi: 10.1055/s-2002-25308.
Transient hypothyroxinemia without elevated thyroid-stimulating hormone (TSH) levels is common in prematurity, especially in very-low-birth-weight (VLBW) infants. The transient hypothyroxinemia of prematurity (THOP) has been seen as a "benign" condition not requiring medical treatment. However, some recent large observational studies have revealed a relationship between THOP and abnormal neurodevelopment. Furthermore, one study showed THOP had twice the risk of brain echolucency, which was the best predictable neurodevelopmental dysfunction, than the premature infants with normal or higher thyroxine levels. The relationships among THOP, illness severity, and neurodevelopmental dysfunction remain unclear. We propose a hypothesis that THOP is associated with abnormal ultrasound and illness severity. We studied 54 infants who were admitted more than 14 days at our neonatal intensive care unit (NICU) with a birth weight <2000 g from March 1999 to March 2000. The infants received serum thyroxine (T4), free-T4, and TSH measurement during the first weeks of life. Most of them had serum thyroxine levels measured at approximately 2 weeks of age. The infants enrolled in the study were examined by at least 1 of 3 cranial ultrasounds during the first weeks of life, illness severity evaluation according to the neonatal therapeutic intervention scoring system (NTISS) score, as well as NICU hospital stay period. Infant were classified as THOP by T4 value <5.3 microg/dL (68 nmol/L), which is 2.6 SD below the mean for term infants in Massachusetts, without elevated TSH value (<20 microIU/mL). After adjusting for some confounding factors, such as gestational age, birth weight, duration of mechanical ventilation, infants with THOP were associated with abnormal cranial ultrasound, illness severity, and lower 1-minute Apgar score. In our studies, THOP was related with brain ultrasound anomaly, neonatal illness, and lower Apgar score at 1 minute. Does early thyroxine intervention improve the prognosis and neurodevelopmental dysfunction? This question requires further investigation.
甲状腺激素水平未升高的短暂性甲状腺素血症在早产儿中很常见，尤其是极低出生体重（VLBW）婴儿。早产儿短暂性甲状腺素血症（THOP）一直被视为一种“良性”状况，无需药物治疗。然而，最近一些大型观察性研究揭示了THOP与神经发育异常之间的关系。此外，一项研究表明，与甲状腺素水平正常或较高的早产儿相比，THOP发生脑实质回声增强（这是可预测的最佳神经发育功能障碍）的风险高出两倍。THOP、疾病严重程度和神经发育功能障碍之间的关系仍不清楚。我们提出一个假设，即THOP与超声异常和疾病严重程度有关。我们研究了1999年3月至2000年3月期间在我们新生儿重症监护病房（NICU）住院超过14天、出生体重<2000 g的54名婴儿。这些婴儿在出生后的第一周内接受了血清甲状腺素（T4）、游离T4和促甲状腺激素（TSH）检测。大多数婴儿在约2周龄时检测了血清甲状腺素水平。研究纳入的婴儿在出生后的第一周内至少接受了3次头颅超声检查中的1次，根据新生儿治疗干预评分系统（NTISS）评分进行疾病严重程度评估，以及记录NICU住院时间。T4值<5.3μg/dL（68 nmol/L）（比马萨诸塞州足月儿平均值低2.6个标准差）且TSH值未升高（<20μIU/mL）的婴儿被归类为THOP。在调整了一些混杂因素，如胎龄、出生体重、机械通气时间后，患有THOP的婴儿与头颅超声异常、疾病严重程度以及1分钟阿氏评分较低有关。在我们的研究中，THOP与脑超声异常、新生儿疾病以及1分钟时较低的阿氏评分有关。早期甲状腺素干预能否改善预后和神经发育功能障碍？这个问题需要进一步研究。
