Williams Fiona L R, Visser Theo J, Hume Robert
Community Health Sciences, University of Dundee, Dundee, Scotland, UK.
Early Hum Dev. 2006 Dec;82(12):797-802. doi: 10.1016/j.earlhumdev.2006.09.007. Epub 2006 Oct 31.
Thyroid hormones are required for normal development of the brain. Transient hypothyroxinaemia is the most common thyroid dysfunction in preterm infants and is defined by temporary low levels of T4, T3 and normal or low TSH. Low T4 levels in preterm infants are associated with persistent neurodevelopmental deficits in cognitive and motor function. Thyroid hormone substitution trials to date are underpowered and show inconsistent results; the question remains -- are low T4 levels simply an epiphenomenon? The aetiology of transient hypothyroxinaemia is multifactorial and the components amenable to correction form the basis of the therapeutic strategy: rectification of iodine deficiency in parenteral nutrition; a reduction of non-thyroidal illnesses and attenuation of their severity; and substitution of drugs that interfere with the hypothalamic-pituitary-thyroid axis. Thyroxine substitution therapy should only be done in the context of clinical trials and only in those infants who are hypothyroxinaemic.
甲状腺激素对大脑的正常发育至关重要。短暂性低甲状腺素血症是早产儿最常见的甲状腺功能障碍,其定义为T4、T3水平暂时降低,TSH正常或降低。早产儿T4水平低与认知和运动功能方面持续的神经发育缺陷有关。迄今为止的甲状腺激素替代试验样本量不足且结果不一致;问题仍然存在——低T4水平仅仅是一种附带现象吗?短暂性低甲状腺素血症的病因是多因素的,可纠正的因素构成了治疗策略的基础:纠正肠外营养中的碘缺乏;减少非甲状腺疾病并减轻其严重程度;停用干扰下丘脑-垂体-甲状腺轴的药物。甲状腺素替代疗法应仅在临床试验的背景下进行,且仅适用于低甲状腺素血症的婴儿。