From the Guidelines
Critical illness myopathy (CIM) can develop as early as 48 hours after ICU admission in critically ill patients. This is based on the most recent evidence from a 2024 guideline on positioning and early mobilisation in the critically ill by an expert panel, published in Intensive Care Medicine 1. The development of CIM is associated with prolonged immobility, and early signs include unexplained muscle weakness, particularly in the limbs and respiratory muscles.
Risk Factors and Prevention Strategies
The risk factors for CIM include prolonged immobility, hyperglycemia, use of neuromuscular blocking agents, and systemic inflammatory response syndrome. Prevention strategies include minimizing sedation, early mobilization, tight glycemic control, and judicious use of corticosteroids and neuromuscular blockers. Daily interruption of sedation and spontaneous breathing trials can help assess muscle strength.
Pathophysiology and Recovery
The pathophysiology of CIM involves muscle protein breakdown, altered calcium homeostasis, mitochondrial dysfunction, and decreased muscle membrane excitability due to the catabolic state and inflammatory mediators present during critical illness. Recovery from CIM is variable, with some patients improving within weeks while others experience prolonged weakness lasting months.
Importance of Early Mobilization
Early mobilization is crucial in preventing CIM, as it can reduce the time to wean from mechanical ventilation and improve functional recovery 1. The European Respiratory Society and European Society of Intensive Care Medicine task force on physiotherapy for critically ill patients recommends early mobilization as part of the physiotherapy protocol 1.
Clinical Implications
In clinical practice, it is essential to prioritize early mobilization and prevention strategies to minimize the risk of CIM and improve patient outcomes. By doing so, healthcare providers can reduce morbidity, mortality, and improve the quality of life for critically ill patients.
From the Research
Timing of Critical Illness Myopathy Development
- Critical illness myopathy (CIM) can develop in intensive care unit (ICU) patients after a brief period, with some studies suggesting it can occur even after a few days of ICU stay 2, 3.
- One study found that CIM may develop in patients hospitalized in the ICU for more than 1 week 4, while another study reported that myopathic changes can occur frequently in patients treated in the ICU, with three main types identified: critical illness myopathy, myopathy with selective loss of myosin filaments, and acute necrotizing myopathy of intensive care 5.
- A recent study on COVID-19 patients with acute respiratory distress syndrome found that 55% of patients developed CIM, with muscle excitability measurements able to discriminate between patients who developed CIM and those who did not, as early as Days 1 and 2 post-intubation 3.
Risk Factors and Clinical Features
- Risk factors for CIM include sepsis or systemic inflammatory response syndrome, severity of multi-organ failure, and the use of corticosteroids and muscle relaxants 4, 2, 5.
- Clinical features of CIM include muscle weakness, failure to wean from mechanical ventilation, and electrophysiological abnormalities 4, 6.
- Muscle biopsies in critically ill patients can demonstrate low glutamine levels, low protein/DNA levels, and high concentrations of extracellular water, which can help diagnose CIM 2.
Diagnosis and Prognosis
- Diagnosis of CIM is based on patient history, results of clinical and electrophysiological examinations, as well as muscle biopsy 3.
- Early diagnosis of CIM is crucial, as it can help identify patients at risk of developing persistent functional disabilities and reduced quality of life 4, 3.
- Muscle excitability measurements may serve as an alternative method for CIM diagnosis and can be used as a tool for early diagnosis and monitoring the development of CIM 3.