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

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.