Urine cortisol levels after burn injury.

The urinary level of cortisol has been assayed in 19 patients with burn injuries of varying severity over a 10-day period. Urine cortisol was increased in all patients over the initial days post burn when compared to normal health volunteers. In patients with the more severe burns mean cortisol levels correlated with the percentage body surface area of the burn. The overall pattern of cortisol excretion was similar in extent and duration to the changes in the levels of serum cortisol described in a previous study (Batstone et al., 1976). Further, urine cortisol excretion correlated with the levels of urine creatinine, magnesium, potassium and the sodium: potassium ratio lending further evidence to an important role of cortisol in peripheral tissue (particularly muscle). Cortisol output was still significantly raised at the end of the study period emphasizing the duration of the cortisol-induced catabolic drive after burn injury.