ICU-Acquired Weakness


Clinically detected weakness in critically ill patients in whom there is no plausible aetiology other than critical illness. Incidence is about 40-50% in patients who develop MOF, severe sepsis and require prolonged ventilation. Hyperglycaemia is an additional risk factor. Steroids, aminoglycosides, NMBD… are all suggested as potential risk factors.



  • Critical Illness Polyneuropathy (CIP)
  • Critical Illness Myopathy (CIM) – this is further classified histologically:
    • Cachectic Myopathy
    • Thick Filament Myopathy
    • Necrotizing Myopathy
  • Critical Illness Neuromyopathy (CINM)



All of:

  • Weakness following critical illness
  • Generalized, symmetrical, flaccid weakness, with cranial nerve spearing
  • Causes not related to underlying critical illness

And either:

  • Mean muscle power <4/5 in all testable muscle groups, on >2 occasions separated by >24 h
  • Ventilator dependence



  • Hypothesised to be a “peripheral neuromuscular failure” due to the inflammatory cytokines, and poor macro & microvascular perfusion implicated in other organ failures.
  • Atrophy and denervation due to lack of use



paperFrom the NEJM Critical Care review series: ICU-Acquired Weakness and Recovery from Critical Illness. N Engl J Med 2014; 370:1626-1635

paperIntensive care unit-acquired weakness, Appletin & Kinsella, CEACCP 2012