Iaglova N V
Vestn Ross Akad Med Nauk. 2013(3):24-32.
Nonthyroidal illness syndrome is characterized by alterations of thyroid status inpatients with severe nonthyroidal illness who are clinically euthyroid. Mechanisms of nonthyroidal illness syndrome are poorly understood and controversial. Our investigations on nonthyroidal illness syndrome in acute endotoxicosis revealed two principal mechanisms of its development. The peripheral mechanism is the first to develop and referred to disturbance of thyrocytes secretory cycle due to increase of thyroglobulin synthesis, endocytosis and decrease of its proteolytic cleavage. It manifests with drop of serum thyroxine, not triiodthyronine, and increase of serum thyroid stimulating hormone. The central mechanism is associated with hypothalamic-pituitary hypofunction developed simultaneously with systemic inflammatory response. Rate of supplementation of the peripheral mechanism with the central one accounts for different types of nonthyroidal illness syndrome with high, normal and low serum levels of thyroid stimulating hormone. Our research showed that thyroid hormone replacement in nonthyroidal illness syndrome could only suppress thyroid function. Unlike thyroid hormones administration of thyroid stimulating hormone restores thyroid hormone secretion in nonthyroidal illness syndrome, decreases endotoxinemia and secretion of proinflammatory cytokines and improves liver function.
非甲状腺疾病综合征的特征是，在临床上甲状腺功能正常的重症非甲状腺疾病患者中，甲状腺状态出现改变。非甲状腺疾病综合征的发病机制尚不清楚且存在争议。我们对急性内毒素血症中非甲状腺疾病综合征的研究揭示了其发展的两个主要机制。外周机制是首先出现的，指的是由于甲状腺球蛋白合成增加、内吞作用以及其蛋白水解裂解减少，导致甲状腺细胞分泌周期紊乱。其表现为血清甲状腺素下降，而非三碘甲状腺原氨酸下降，以及血清促甲状腺激素升高。中枢机制与下丘脑 - 垂体功能减退有关，它与全身炎症反应同时发生。外周机制与中枢机制的补充比例导致了促甲状腺激素血清水平高、正常和低的不同类型的非甲状腺疾病综合征。我们的研究表明，在非甲状腺疾病综合征中补充甲状腺激素只会抑制甲状腺功能。与甲状腺激素不同，给予促甲状腺激素可恢复非甲状腺疾病综合征中的甲状腺激素分泌，降低内毒素血症和促炎细胞因子的分泌，并改善肝功能。
