Critical Illness Neuromuscular Disease

Definitions

• Neuromuscular disease occurs in >25% of patients in ICU ventilated for >7days
• Includes critical illness myopathy and polyneuropathy

Critical Illness Myopathy

Epidemiology

• Risk factors
• Strongest risk factor is use of IV glucocorticoids
• Use of paralytic agents

Clinical manifestations

• Flaccid quadriparesis – proximal usually more than distal
• Failure to wean from ventilator
• Facial muscle weakness may occur but extraoccular muscle weakness is rare
• Normal sensory function

Diagnosis

• NCS/EMG
• CK
• Elevated in ~50%

Treatment

• Discontinue steroids
• Largely reversible over weeks to months.

Critial Illness Polyneuropathy

• Most common in patients in ICU >1-2 weeks
• Strong association with sepsis
• Possibly due to micovascular injury to nerves during sepsis

Clinical Features

• Sensorimotor polyneuropathy
• Limb and muscle weakness and atrophy
• Reduced or absent deep tendon reflexes
• Loss of peripheral sensation
• Relative preservation of cranial nerve function
• NOTE: often combined with critical illness myopathy

Diagnosis

• NCS
• Sensory and motor axonal neuropathy
• Nerve amplitudes should be <80% of LLN in >2 nerves
• Normal F-wave
• CSF and CK should be normal

Treatment

• No specific treatments
• Recovery of weeks to months, however permanent deficits may remain