Suppression and recovery of the hypothalamic function after high-dose corticosteroid treatment in preterm infants.
BACKGROUND
High-dose systemic dexamethasone is effective in facilitating extubation of ventilated infants with bronchopulmonary dysplasia. Although the suppression and recovery of pituitary-adrenal response had been assessed after corticosteroid treatment in very low birth weight infants, its effect on hypothalamic function has not been longitudinally monitored.


OBJECTIVE
This study was designed to assess the longitudinal hypothalamic response before, during and 4 weeks after a 3-week dose-tapering course of systemic dexamethasone treatment.


METHODS
Twenty very low birth weight infants had blood collected for corticotropin-releasing hormone, ACTH and cortisol measurements immediately before starting dexamethasone (week 0), after receiving the maximum dose of treatment (week 1), at the end of the 3-week course (week 3) and 4 weeks after stopping corticosteroids (week 7).


RESULTS
All circulating hormone concentrations were significantly suppressed during the treatment period at week 1 and week 3 compared with pretreatment concentrations at week 0 (p < 0.001). The recovery of pituitary function started early soon after week 1, whereas that of hypothalamus and adrenal functions started after the end of the dexamethasone course. Plasma ACTH concentration at week 7 had returned to the pretreatment level, but plasma corticotropin-releasing hormone (p < 0.05) and serum cortisol (p < 0.001) concentrations remained significantly suppressed. Partial recovery of hypothalamic and adrenal function was observed at week 7 (62 vs. 36% of their pretreatment levels, respectively).


CONCLUSIONS
Our findings suggest that the hypothalamic function is suppressed during systemic corticosteroid treatment but partial recovery occurs 4 weeks after stopping therapy. Even in preterm infants, the hypothalamic-pituitary-adrenal axis behaves in a similar manner as in adult subjects and the pituitary function recovers earlier than that of hypothalamus and adrenals.
Ng
P C
PC
Department of Pediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, SAR, China. pakcheungng@cuhk.edu.hk
Lam
C W K
CW
Lee
C H
CH
Chan
I H S
IH
Wong
S P S
SP
Fok
T F
TF
D000324:Adrenocorticotropic Hormone / Q000097:blood; D001997:Bronchopulmonary Dysplasia / Q000628:therapy; D003346:Corticotropin-Releasing Hormone / Q000097:blood; D003907:Dexamethasone / Q000008:administration & dosage*; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000502:physiology; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood; D019102:Infant, Very Low Birth Weight / Q000097:blood; D016018:Least-Squares Analysis; D008137:Longitudinal Studies; D008297:Male; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000502:physiology; D011446:Prospective Studies; D015300:Ventilator Weaning / Q000379:methods
D005938:Glucocorticoids; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone