Abstract
BACKGROUND: Little is known of the optimal dose and administration schedule of hydrocortisone in critically ill patients with congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency. AIM: To determine plasma cortisol concentrations after intravenous administration of hydrocortisone in children with CAH and to relate these to plasma cortisol concentrations achieved by endogenous secretion in the stress of critical illness in previously healthy children. METHODS: Plasma cortisol concentrations were measured in 20 patients with classical CAH (median age 11.2 years, range 6.1-16.4) following intravenous administration of hydrocortisone 15 mg/m(2); and in 60 critically ill mechanically ventilated children (median age 2.5 years, range 0.25-16.3) on admission to the paediatric intensive care unit and for 24 hours thereafter. RESULTS: In the CAH patients, plasma cortisol reached a mean peak of 1648.3 nmol/l (SD 511.9) within 10 minutes of the intravenous bolus, and fell rapidly thereafter; levels remained greater than 450 nmol/l for 2.5 hours only. In critically ill children, mean plasma cortisol on admission to the intensive care unit was 727 nmol/l (SD 426.1). Cortisol concentrations remained raised during the first 24 hours. CONCLUSIONS: Critically ill patients with classical CAH may be best managed with a single intravenous hydrocortisone bolus followed by a constant rate infusion of hydrocortisone.