What are the types of Intensive Care Unit (ICU) acquired weakness?

From the Guidelines

ICU-acquired weakness (ICUAW) encompasses three main types: critical illness polyneuropathy (CIP), critical illness myopathy (CIM), and critical illness neuromyopathy (CINM). These conditions are characterized by:

• Critical illness polyneuropathy (CIP): affects peripheral nerves, causing sensory and motor deficits with preserved facial muscle function
• Critical illness myopathy (CIM): involves direct muscle damage with normal sensory function but reduced muscle strength and atrophy
• Critical illness neuromyopathy (CINM): a combination of both conditions, presenting with features of both nerve and muscle involvement These conditions typically develop in critically ill patients due to multiple factors including systemic inflammation, medication effects (particularly corticosteroids and neuromuscular blocking agents), immobility, hyperglycemia, and multi-organ failure, as reported in the guideline on multimodal rehabilitation for patients with post-intensive care syndrome 1. Diagnosis involves clinical examination, electrophysiological studies, and sometimes muscle biopsy. Prevention strategies include minimizing sedation, early mobilization, glycemic control, and judicious use of corticosteroids and neuromuscular blockers, as recommended in the American Thoracic Society clinical practice guideline 1. Recovery varies widely, with some patients improving within weeks while others experience persistent weakness for months or years, highlighting the importance of early recognition and preventive measures in ICU care, as emphasized in the guideline on multimodal rehabilitation for patients with post-intensive care syndrome 1. The reported prevalence of PICS, which includes ICUAW, varies, but it is estimated that 50-70% of intensive care unit survivors are affected, with effects persisting for 5-15 years after ICU hospitalization 1. Therefore, early recognition and prevention of ICUAW are crucial to improve outcomes in critically ill patients.

From the Research

Types of ICU Acquired Weakness

• Critical illness polyneuropathy (CIP) 2, 3, 4, 5
• Critical illness myopathy (CIM) 2, 3, 4, 5
• Critical illness neuromyopathy (CIPNM) or overlap syndrome 4
• Disorders of neuromuscular junction transmission 5

Characteristics of Each Type

• CIP: affects peripheral nerves, can lead to weakness in limb and respiratory muscles 3, 4
• CIM: affects skeletal muscle, can lead to weakness in limb and respiratory muscles 3, 4
• CIPNM: an overlap of CIP and CIM, affecting both peripheral nerves and skeletal muscle 4

Diagnosis and Management

• Diagnosis: careful physical and neurological examinations, electrophysiological testing, and in rare cases nerve and muscle biopsies 3, 5
• Management: preventive strategies include avoiding modifiable risk factors, early mobilization, achieving euglycemia, and nutritional optimization 2, 4, 6