Intensive-care-unit-acquired muscle weakness.

Neuromuscular abnormalities culminating in skeletal-muscle weakness occur very commonly in critically ill patients. Intensive-care-unit (ICU) acquired neuromuscular abnormalities are typically divided into 2 discrete classes: polyneuropathy and myopathy. However, it is likely that these 2 entities commonly coexist, with myopathy being the most common cause of weakness. Major risk factors for ICU-acquired neuromuscular abnormalities include sepsis, corticosteroid administration, and hyperglycemia, with other associated factors including neuromuscular blockade and increasing severity of illness. The pathogenesis of these disorders is not well defined, but probably involves inflammatory injury of nerve and/or muscle that is potentiated by functional denervation and corticosteroids. ICU-acquired neuromuscular abnormalities are associated with multiple adverse outcomes, including higher mortality, prolonged duration of mechanical ventilation, and increased length of stay. The only intervention proven to reduce the incidence of ICU-acquired neuromuscular abnormalities is intensive insulin therapy. Additional research is necessary to better delineate the causes and pathogenesis of these disorders and to identify potential preventive and therapeutic strategies. In addition, consensus guidelines for its classification and diagnosis are needed.