Myopathy and Neuropathy Acquired in the Intensive Care Unit

Acquired weakness in critically ill patients is common, affecting between one-third to one-half of patients in the intensive care unit (ICU). Exposure to simultaneous stressors such as metabolic derangements, fluid and electrolyte shifts, infection, catabolic stress, and medications put patients in the ICU at risk for damage to both nerve and skeletal muscle with substantial and often lasting morbidity. Critical illness polyneuropathy is a length-dependent, axonal peripheral neuropathy occurring in patients in the ICU and unrelated to the primary illness. Critical illness myopathy is an ICU-associated muscle disorder occurring independently of denervation and uniquely identified by electrophysiologic and histologic characteristics.