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Neuromuscular weakness related to critical illness

David Lacomis, MD
Section Editor
Jeremy M Shefner, MD, PhD
Deputy Editor
John F Dashe, MD, PhD


Neuromuscular weakness is a common occurrence in patients who are critically ill. Weakness is partly a consequence of improved survival in patients with multiorgan failure and sepsis, but may be associated with treatments administered in the intensive care unit (ICU).

Neuromuscular weakness in the ICU is most often due to critical illness myopathy, critical illness polyneuropathy, or a combination of the two. This topic will review the peripheral neuromuscular disorders of critical illness.


Neuromuscular weakness in the intensive care unit (ICU) is most often due to critical illness myopathy, critical illness polyneuropathy (CIP), or a combination of the two. Some authors apply the term "intensive care unit-acquired weakness (ICUAW)" for patients who have clinically detected weakness with no plausible cause other than critical illness [1].

It is likely that reduction of nerve excitability (ie, inactivation of sodium channels) and axon degeneration (the currently accepted mechanism of CIP) may represent different ends of a single pathophysiologic spectrum that varies according to the severity of the inflammatory process in CIP [2], and that muscle membrane inexcitability, myosin loss, and muscle necrosis comprise the pathophysiologic spectrum in critical illness myopathy (CIM).

Critical illness myopathy — The most common form of ICU-acquired myopathy is CIM [3,4]. This disorder is also known by other names, including acute quadriplegic myopathy and thick filament myopathy.

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Literature review current through: Nov 2017. | This topic last updated: Nov 29, 2017.
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