Today we’re talking about a topic that is relevant for all critical care physicians but under-examined: ICU Acquired Weakness. We are joined by two excellent guests to walk through a case and discuss the diagnosis, pathophysiology, prevention, and treatment of ICU Acquired Weakness. Check out our associated infographics and key learning points below.
Meet Our Guests
Jim Devanney is a Physiatrist who just completed a neurocritical care fellowship at BIDMC. He is transitioning to a clinical associate position at University Health Network – University of Toronto where he will be working as a PM&R consultant within the ICU.
Kalaila Pais is a third year internal medicine resident at BIDMC, interested in pulmonary and critical care and medical education and is returning for her third Pulm PEEPs episode.
Key Learning Points
Definition & Clinical Presentation* ICU-AW refers to new-onset, generalized muscle weakness that arises during critical illness, not explained by other causes.It typically presents as:* Symmetric, proximal > distal weaknessRespiratory muscle involvementPreserved cranial nerve functionNo sensory deficits in myopathy (sensory loss points toward neuropathy)Differential Diagnosis Using Neuroanatomical ApproachAn anatomical approach (central → peripheral) helps localize the etiology weakness* CNS: trauma, stroke, encephalitis, seizuresAnterior horn cells: viral myelitis, motor neuron diseasePeripheral nerves: Guillain-Barré, vasculitis, critical illness polyneuropathy (CIP)Neuromuscular junction: myasthenia gravis, botulism, Lamber EatonMuscle: rhabdomyolysis, inflammatory or drug-induced myopathies, critical illness myopathy (CIM)Subtypes of ICU-AW* Critical Illness Myopathy (CIM):* Muscle dysfunctionEarly onset (within 48 hrs)Sensation intactproximal > distal weakness* Critical Illness Polyneuropathy (CIP):* Nerve involvementDistal > proximal weakness, sensory deficits
* Critical Illness Polyneuromyopathy (CIPNM): Combination of bothDiagnosis* Medical Research Council Score (MRC-SS):* Score < 48: ICU-AW* Score < 36: severe ICU-AW* Handgrip dynamometry: <11 kg (men), <7 kg (women)* Electrophysiology: EMG/NCS to distinguish CIM vs CIP* Muscle ultrasound: bedside monitoring* MRI/CT/Muscle biopsy: rarely used due to practical limitationRisk FactorsModifiable:* Hyper/hypoglycemia* Electrolyte derangement* Parenteral nutrition* Immobility* Medications (steroids, NM blockers, sedatives, aminoglycosides)Non-modifiable:* Age, female sex, comorbidities* Severity of illness, prolonged ventilation* Sepsis, multi-organ failure Management & Prevention* Prevention is key:* Early treatment of sepsis and inflammation* Glycemic control* Early enteral nutrition* Minimize sedation (A-F bundle)* Early mobilization and physical therapy* NMES (neuromuscular electrical stimulation): emerging therapy, needs more evidenceOutcomes* Short-term: increased LOS, ventilation duration, mortality* Long-term: decreased function, discharge to rehab, prolonged recoveryFinal Takeaways* Prevention is crucial — start interventions early.* Systematic approach to ICU weakness helps rule out dangerous mimics.* ICU-AW is common but often under-recognized — awareness and early rehab can significantly impact recovery.
Infographics
References and Further Reading
Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU. Devlin JW, Skrobik Y, Gélinas C, et al. Critical Care Medicine. 2018;46(9):e825-e873. doi:10.
