Disruption of bone and skeletal muscle in severe burns.
Severe burn injury triggers the body's nonspecific adaptive responses to acute insult, including the systemic inflammatory and stress responses, as well as the sympathetic response to immobilization. These responses trigger inflammatory bone resorption followed by glucocorticoid-induced apoptosis of osteoblasts and probably osteocytes. Because these patients are catabolic, they suffer concomitant muscle wasting and negative nitrogen balance. The use of anabolic agents such as recombinant human growth hormone and oxandrolone results in improved bone mineral content and muscle strength after approximately 1 year. Use of bisphosphonates within the first 10 days of a severe burn completely blocks the resorptive bone loss and has the added advantage of appearing to preserve muscle protein from excessive breakdown. The mechanism for the protective effect on muscle is not currently known. However, if the effect of bisphosphonates on muscle can be confirmed, it raises the possibility that bone communicates with muscle.
Department of Orthopaedic Surgery and Rehabilitation, University of Texas Medical Branch and Shriners Hospitals for Children , Galveston, TX, USA.
Gordon L
GL
Klein