Changes in calcium and phosphate and their regulating hormones in patients with severe burn injuries

Changes in the calcium- and phosphate homeostasis and its regulating hormones calcitonin (CT) and parathyroid hormone (PTH) are of great importance for several pathophysiological reactions after trauma. In this study calcium, phosphate, CT, PTH and nor-adrenaline, were followed during 14 days after trauma in 20 patients with severe burn injuries. The results showed significantly reduced serum phosphate (S-P) during the first week after trauma, and low ionized calcium fraction (CaF) during the 14 post-traumatic days that were studied. Urinary calcium output was low, about 4.5 mmol/day and urinary phosphate output was as high as 30 mmol/day, despite the low S-P. Plasma nor-adrenaline was elevated with maximum concentrations 6 days after trauma. CT was very high with levels around 1 000 pmol/l after one week. PTH remained within the reference interval, although a statistically significant increase was observed four days after the trauma. The results suggest that the observed changes in calcium- and phosphate homeostasis were related to the humoral response to trauma.