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Table 1 Clinical, electrophysiological, and histological features of intensive care unit-acquired weakness (ICUAW)

From: ICU-acquired weakness: what is preventing its rehabilitation in critically ill patients?

Investigation CIP CIM CINM
Physical examination Distal muscle weakness Proximal muscle weakness Proximal and distal muscle weakness
  Distal sensory deficit Normal sensory testing Distal sensory deficit
  Normal or depressed deep tendon reflexes Normal or depressed deep tendon reflexes Depressed deep tendon reflexes
Electrophysiology studies Decreased CMAP and decreased SNAP Decreased CMAP and normal SNAP Decreased CMAP and SNAP
  Normal MUAP Decreased MUAP Decreased MUAP
  Normal or near-normal conduction velocity EMG shows short duration, low amplitude activity EMG shows short duration, low-amplitude activity
Histology Axonal degeneration of distal motor and sensory nerves Thick filament (myosin) loss, type II fiber (fast twitch) atrophy, necrosis Axonal degeneration and evidence of loss in myosin, type II fiber atrophy, and necrosis
  1. CIM = critical illness myopathy; CINM = critical illness neuromyopathy; CIP = critical illness polyneuropathy; CMAP = compound muscle action potential; EMG = electromyography; MUAP = muscle unit action potential; SNAP= sensory nerve action potential.