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

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From the Guidelines

ICU-acquired weakness (ICUAW) is classified into three main types: critical illness polyneuropathy (CIP), critical illness myopathy (CIM), and critical illness neuromyopathy (CINM) 1. These conditions are characterized by different primary sites of pathology, with CIP involving damage to peripheral nerves, CIM affecting skeletal muscles directly, and CINM representing a combination of both nerve and muscle involvement. The classification of ICUAW is crucial for understanding the underlying pathophysiology and for guiding diagnosis and treatment. Some key points to consider in the classification of ICUAW include:

  • Critical illness polyneuropathy (CIP) involves damage to peripheral nerves, causing sensory and motor deficits with preserved muscle function 1.
  • Critical illness myopathy (CIM) affects skeletal muscles directly, resulting in muscle weakness while nerve conduction remains intact 1.
  • Critical illness neuromyopathy (CINM) represents a combination of both nerve and muscle involvement, which is the most common presentation in critically ill patients 1. The diagnosis of ICUAW can be made using a combination of physical examination, electrophysiological testing, and other diagnostic methods, such as EMG, nerve conduction studies, and muscle biopsy 1. Early recognition and diagnosis of ICUAW are essential for implementing effective preventive and therapeutic strategies, such as early mobilization, minimizing sedation, controlling hyperglycemia, and judicious use of corticosteroids and neuromuscular blockers 1. Overall, the classification of ICUAW into CIP, CIM, and CINM provides a framework for understanding the complex pathophysiology of this condition and for guiding clinical practice.

From the Research

Classification of ICU Acquired Weakness

The classification of ICU acquired weakness can be broken down into several subcategories, including:

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

Characteristics of Each Subcategory

Each subcategory has distinct characteristics, including:

  • Critical illness polyneuropathy: affects peripheral nerves 3, 4, 5
  • Critical illness myopathy: affects skeletal muscle 3, 4, 5
  • Critical illness neuromyopathy: affects both peripheral nerves and skeletal muscle 2, 3, 4

Diagnosis and Management

Diagnosis of ICU acquired weakness is typically made using a combination of clinical and electrophysiological tools 2, 6, 3, 4, 5. Management strategies focus on early mobilization, achieving euglycemia, and nutritional optimization 6, 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Pathophysiology and management of critical illness polyneuropathy and myopathy.

Journal of applied physiology (Bethesda, Md. : 1985), 2021

Research

Neuromuscular complications of critical illness.

Handbook of clinical neurology, 2013

Research

ICU-acquired weakness.

Intensive care medicine, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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