Muscle matters: Transforming the care of intensive care unit acquired sarcopenia and myosteatosis

Abstract

Intensive care unit (ICU) acquired sarcopenia and myosteatosis are increasingly recognized complications of critical illness, characterized by a rapid loss of skeletal muscle mass, quality, and function. These conditions result from a complex interplay of systemic inflammation, immobilization, catabolic stress, mitochondrial dysfunction, and immune dysregulation, often culminating in impaired recovery, prolonged hospitalization, and increased long-term mortality. First identified in survivors of sepsis and prolonged mechanical ventilation, these muscle abnormalities were initially described using computed tomography-based assessments of muscle area and density. Subsequent advances in imaging, biomarker discovery, and functional testing have enabled earlier detection and risk stratification across diverse ICU populations. While nutritional optimization and early mobilization form the cornerstone of current prevention and treatment strategies, the emergence of novel approaches, including automated artificial intelligence-based screening, neuromuscular electrical stimulation, and targeted pharmacologic therapies, has broadened the clinical scope of interventions. Despite their significant prognostic implications, ICU-acquired sarcopenia and myosteatosis remain under-recognized in routine critical care practice. This mini-review aims to synthesize current knowledge regarding their pathophysiology, available diagnostic modalities, prognostic relevance, and the evolving landscape of therapeutic strategies for long-term functional recovery in critically ill patients.

Keywords: Intensive care unit acquired sarcopenia; Intensive care unit acquired weakness; Myosteatosis; Muscle atrophy; Muscle weakness

Core Tip: The growing recognition of intensive care unit (ICU)-acquired sarcopenia and myosteatosis underscores their profound impact on both short-term and long-term patient outcomes. They result from a convergence of metabolic, inflammatory, endocrine, and neuromuscular disturbances. These conditions lead to prolonged ventilation, extended ICU stays, higher mortality, and increased healthcare costs. With advancements in diagnostic technologies, such as computed tomography imaging and ultrasound, the link between ICU-related factors (e.g., mechanical ventilation, sepsis, and systemic inflammation) and muscle loss has become clearer. Early identification and management of these conditions are crucial for improving recovery rates and reducing the risk of disability. Current best practices emphasize a “bundled” approach: Optimize protein and calorie delivery, avoid deep sedation, when possible, mobilize early and often, and address deliriogenic and inflammatory factors that impede participation in rehab. These interventions, when implemented together, act synergistically to preserve muscle.