EVALUATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS IN A PAEDIATRIC INTENSIVE CARE UNIT.

Abstract

Background: Relative adrenal insufficiency (RAI) is the inadequate production of cortisol due to dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis during a severe illness. We evaluated the HPA axis and RAI in a tertiary pediatric intensive care unit (PICU).

Methods: A total of 100 PICU patients were included in this prospective cohort study. Basal serum levels of adrenocorticotropic hormone (ACTH), cortisol values were compared with those in the control group. A low-dose ACTH stimulation test was performed in patients with basal cortisol levels below 18 µg/dL.

Results: The basal cortisol levels of the PICU patients were significantly higher than those of the control group (P < 0.05). All tested patients (n= 24) had delta cortisol levels > 9 µg/dL and a peak cortisol response > 18 µg/dL. Basal cortisol levels were positively correlated with Pediatric Risk of Mortality (PRISM) III scores (P < 0.05; r = 0.363). The basal or stimulated cortisol levels of the patients who received glucocorticoid treatment were higher than the cut-off levels.

Conclusions: High basal or stimulated cortisol levels are indicative of disease severity in the acute phase of stress. Patients with very high cortisol levels should be particularly carefully monitored because of the high mortality risk.