ICU-acquired weakness: critical illness polyneuropathy and myopathy

Also known as ICU-acquired weakness · ICUAW · Critical illness polyneuropathy · CIP · Critical illness myopathy · CIM · Critical illness neuromyopathy

ICU-acquired weakness (ICUAW): muscle weakness developing during ICU stay, not attributable to other causes. Affects 25-50% of long-stay ICU patients. Types: (1) CIP (critical illness polyneuropathy) — AXONAL sensorimotor polyneuropathy (distal). (2) CIM (critical illness myopathy) — MYOPATHY (muscle fibre atrophy/necrosis). (3) Combined (CINM — most common). Risk factors: sepsis, multi-organ failure, prolonged immobilisation, corticosteroids, neuromuscular blockade, hyperglycaemia. Diagnosis: clinical (MRC sum score <48), electrophysiology (NCS/EMG), muscle biopsy. Prevention: minimise sedation, early mobilisation, glycaemic control, avoid steroids/NMBA if possible, nutrition. Treatment: supportive (rehabilitation, physiotherapy). Recovery: months-years, may be incomplete.

high33 referencesUpdated 26 July 202631 min readSource-verified · Sept 2026

Checked against its sources on 3 Sept 2026

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8 MCQs

Meet the patient

A 64-year-old man is day 16 of an ICU admission for pneumococcal pneumonia that spiralled into septic shock and ARDS. He has had five days of a cisatracurium infusion and a week of hydrocortisone for vasopressor-refractory shock. Now that sedation has been lightened he is awake and cooperative — but he has failed three spontaneous breathing trials and cannot lift his arms or legs off the bed. His limbs are flaccid and areflexic with reduced sensation distally, and he asks you why he cannot move.^[17]

The two questions that decide his next month are the two that decide every ICUAW case: is this weakness critical-illness weakness, or a reversible mimic? (phosphate, residual blockade, electrolytes) and how do I stop it getting worse from here? (lighten the sedation, get him moving, control the glucose, spare the steroids and the paralytic). Hold those two questions and the whole topic falls into place.^[17]

References33Show

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