Burn-induced hypermetabolism and skeletal muscle dysfunction

Abstract

Critical illnesses, including sepsis, cancer cachexia and burn injury, invoke a milieu of systemic metabolic and inflammatory derangements that ultimately results in increased energy expenditure leading to fat and lean mass catabolism. Burn injuries present a unique clinical challenge given the magnitude and duration of the hypermetabolic response in comparison to other forms of critical illness, which drastically increase the risk of morbidity and mortality. Skeletal muscle metabolism is particularly altered as a consequence of burn-induced hypermetabolism as it primarily provides a main source of fuel in support of wound healing. Interestingly, muscle catabolism is sustained long after the wound has healed, indicating that additional mechanisms beyond wound healing are involved. In this review, we discuss the distinctive pathophysiological response to burn injury with a focus on skeletal muscle function and metabolism. We first examine the diverse consequences on skeletal muscle dysfunction between thermal, electrical and chemical burns. We then provide a comprehensive overview of the known mechanisms underlying skeletal muscle dysfunction that may be attributed to hypermetabolism. Lastly, we review the most promising current treatment options to mitigate muscle catabolism, and by extension improve morbidity and mortality, and end with future directions which have the potential to significantly improve patient care.