Early adrenocortical recovery after glucocorticoid therapy in children with leukemia.
The duration of glucocorticoid-induced inhibition that occurs in the hypothalamic-pituitary-adrenal (HPA) axis after discontinuation of treatment is controversial. The main objective of this prospective study was to evaluate the inhibition of the HPA axis by dexamethasone in children and adolescents with acute lymphoid leukemia. Thirty-five patients (median age of 6.9 yr) were evaluated. A stimulus test with ovine CRH (1 microg/kg) was performed before the introduction of dexamethasone (6 mg/m2.d for 28 d), in the 8th and 28th days of glucocorticoid therapy, and 48 h and 1 month after discontinuation of glucocorticoid therapy. Suppression of the basal secretion as well as the maximum concentration of ACTH occurred during glucocorticoid therapy (P < 0.01). The pituitary function before the introduction of dexamethasone was similar to the one seen 48 h and 1 month after withdrawing it. Suppression of the adrenal function was detected during glucocorticoid therapy, which persisted for 48 h after the steroid was removed from treatment (P < 0.01). One month after ceasing the administration of the glucocorticoid, the adrenal function was similar to that before glucocorticoid therapy. According to these results, a clinical and laboratory follow-up of the HPA axis in the month after the cessation of dexamethasone therapy is suggested to determine glucocorticoid replacement.