Critical Care · Year 4 · from Critical Care
Case 3: Early Mobility in ICU-Acquired Weakness Prevention
Clinical Image
Source: Wikimedia Commons - Physical Therapy - CC BY-SA 3.0
Case Presentation
A 58-year-old man is admitted to the surgical ICU with septic shock from a perforated appendix requiring emergent laparotomy. He requires mechanical ventilation for 12 days, norepinephrine for 7 days, and receives high-dose corticosteroids for vasopressor-refractory shock. By day 14, he is hemodynamically stable off vasopressors and sedation has been weaned. However, when asked to lift his arms, he demonstrates profound symmetric weakness, barely able to overcome gravity (MRC grade 2/5 in proximal muscles). He cannot participate in spontaneous breathing trials due to rapid shallow breathing. The neurology consult diagnoses ICU-acquired weakness (likely combined critical illness polyneuropathy and myopathy) based on clinical examination and EMG findings. An aggressive early mobility program is initiated: day 1 begins with passive range of motion, day 3 progresses to active-assisted exercises in bed, day 5 achieves sitting at edge of bed with two-person assist, and day 8 accomplishes transfer to chair. Physical and occupational therapy visit twice daily. Adequate protein nutrition at 1.5 g/kg/day supports muscle recovery. Corticosteroids are weaned as clinically appropriate. After 3 weeks of intensive rehabilitation, his MRC sum score improves from 32/60 to 48/60, he successfully weans from the ventilator, and he transfers to acute rehabilitation. At 3-month follow-up, he has returned to independent function.
Key Learning Points
- ICU-acquired weakness affects 25-50% of patients with prolonged ICU stays and is caused by critical illness polyneuropathy (CIP), critical illness myopathy (CIM), or both
- Risk factors include sepsis, prolonged immobility, corticosteroids, neuromuscular blocking agents, and hyperglycemia
- The MRC sum score tests strength in 6 muscle groups bilaterally (total 60 points); scores less than 48 define ICU-acquired weakness
- Early mobilization is the most effective prevention and treatment, with benefits including reduced delirium, shorter ventilator days, improved functional outcomes, and shorter ICU/hospital stay