Hormone levels in children during the first week of ICU-admission: is there an effect of adequate feeding?

Abstract

Background & aims: To evaluate the course of hormonal parameters in relation to clinical parameters, illness severity and nutritional intake in children admitted to the pediatric ICU during the first week of admission.

Methods: Prospective, observational study. Levels of triiodothyronine (T3), reverse T3 (rT3), ratio T3/rT3 and insulin-like growth factor I (IGF-1) were evaluated in 84 critically ill children (50 term neonates and 34 children aged 32 d-15 yr) admitted to our multidisciplinary tertiary pediatric intensive care unit within 24 h after admission, on days 4 and 6 after admission. Changes in hormones levels over time were related to illness severity, C-reactive protein-levels and the adequacy of feeding.

Results: For both age groups IGF-1 levels remained low until day 4, but at day 6 IGF-1 levels were significantly higher than admission level. In 88% and 89% of the older children, T3 levels remained below normal at days 4 and 6, respectively. In both age groups, rT3 levels declined significantly over time, whereas the ratio T3/rT3 increased. The increases in IGF-1, T3 and ratio T3/rT3 and decrease in rT3 were significantly associated with decreases in CRP-levels. No significant relations were found between changes in IGF-1 and thyroid hormone levels during admission and the adequacy of energy and protein intake.

Conclusions: During the first week of ICU-admission, abnormalities in levels of IGF-1, T3 and rT3 were frequently observed in critically ill children, especially in the children aged >1 month. The adequacy of feeding did not seem to affect the normalization of IGF-1 and thyroid hormone levels.