Introduction: A severe burn causes increased levels of urine cortisol and catecholamines. However, little is known about the magnitude of this increase or how and when the levels return to normal. The purpose of this study was to determine in a large clinical prospective trial the acute and long-term pattern of urine cortisol and catecholamine expression in severely burned children.

Methods: Pediatric patients with burns greater than 40% total body surface area (TBSA), admitted to our unit over a 6-year period, were included into the study. Clinical data including length of stay, number of operations, and duration and number of infections were determined. Patients had regular 24-hour urine collections during their acute admission and reconstructive periods. Urine collections were analyzed for cortisol, epinephrine and norepinephrine. Each urine cortisol was compared with age adjusted reference ranges. Ninety-five percent confidence intervals and analysis of variance (ANOVA) analysis were used where appropriate.

Results: Two-hundred twelve patients were included in the study (f=75, m=137), with a mean (±SEM) TBSA of 58±1%, 3^rd degree 45±2%, and 9±0.4 years of age. Urinary cortisol levels were significantly increased (3–5 fold) up to 100 days post burn and then approached normal levels, p<0.05. The rise in urine cortisol is significantly higher in male than female patients (p<0.05). Early hypercortisolemia is associated with increased duration of severe infection, p<0.05. Persistent hypercortisolemia is associated with increases in both infection rates and duration of severe infection, p<0.05. Urinary catecholamines showed a significant increase at 11–20 days post burn, p<0.05. Urinary norepinephrine levels were significantly increased up to 20 days and then returned to normal, p<0.05.

Conclusions: Urinary levels of cortisol, epinephrine and norepinephrine are significantly increased following a major burn. Early hypercortisolemia is associated with increased duration of severe infection. Persistent hypercortisolemia is associated with increases in both infection rates and duration of severe infection.