Critical Illness Myopathy

Abstract

Myopathy is a general term for every potential muscle problem (primary structural or functional impairment). One of the most important causes of myopathy in critically ill patients is critical illness myopathy (CIM) which causes failure of weaning from ventilator. It accounts for 42% of weakness among patients in the surgical and medical ICUs. Many risk factors are accused of precipitating CIM such as systemic inflammation, hyperglycemia, medications, electrolyte disturbances and immobility. The main acute myopathic disorders that need ICU admission include rhabomyolysis, neuroleptic malignant syndrome, serotonin syndrome and malignant hyperthermia. Physical examination depends on the patient‘s cooperation and conscious level to apply a standardized bedside muscle examination that reveals diffuse weakness in both limb and neck muscles, depressed or absent tendon reflexes, facial muscles may be involved, but extraocular muscles are rarely affected and other muscles supplied by cranial nerves are spared. About 50% of affected patients shows early creatine kinase rise. EMG shows low-amplitude or absent motor responses. Needle electrode examination shows fibrillation potential activity reflecting segmental necrosis. Muscle biopsy is not necessary except when the diagnosis is uncertain and the suspected disease will need specific therapies such as GBS