Evidence for developmental hypopituitarism in ill preterm infants.
OBJECTIVE
The relationship between the concentrations of cortisol and T4 with outcome in the preterm infants has not been well studied.


METHODS
Mean cortisol (days 2, 4, and 6) and T4 values were correlated to gestational age, illness, and outcome in 210 infants using ANOVA.


RESULTS
Cortisol significantly decreased and T4 increased across gestational age. For both hormones, higher values were found in infants on low ventilatory settings. Combined lower cortisol (mean < 5 microg/dl (138 nmol/l)) and T4 concentrations (<4 microg/dl) were found in 20/210 (9.5%) infants; 11/20 in a high-acuity group (22% of total) including 48% (12/25) of the deaths. Lower cortisol values were found in infants who died (p<0.005) in contrast to a lack of relationship with T4.


CONCLUSIONS
Lower cortisol values in infants who died are consistent with the role for cortisol in survival. Combined lower cortisol and T4 concentrations in infants who failed to improve clinical status may suggest that these hormones are markers of a poor physiological state. In contrast, we suggest that these results reflect a developmental hypopituitarism, a necessary role for cortisone and T4 in successful early neonatal transition. Treatment of hypothyroidism in the setting of coexistent low cortisol concentrations (central dysfunction of the hypothalamic-pituitary axes) is known to precipitate cortisol crisis in older populations. Therefore, we caution against treatment of low neonatal thyroid concentrations until more is known about the relationship between cortisol and T4 preterm infant population.
Scott
Susan M
SM
UNM Children's Hospital, University of New Mexico School of Medicine, MSC 10-5590, 1 University of New Mexico, Albuquerque, NM 87131-5311, USA.
Cimino
Daniel F
DF
D005865:Gestational Age; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007018:Hypopituitarism / Q000097:blood*; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000097:blood*; D013974:Thyroxine / Q000097:blood*
D013974:Thyroxine; D006854:Hydrocortisone