The incidence of muscle weakness was determined in 830 children (3 months to 17 years of age) admitted for >24 hours to the intensive care unit over a 1-year period at the Hospital for Sick Children, Toronto, Canada. Generalized weakness developed in 14 (1.7%), and 4 failed repeated attempts to extubate. The age distribution was bimodal, with 3 under age 3 years and 11 age 10 or older. Eleven had multiple organ dysfunction and 9 had sepsis. Most received corticosteroids, neuromuscular blocking agents, or aminoglycoside antibiotics. Eight of the 14 were organ or bone marrow transplant recipients. EMG findings in 5 were abnormal and myopathic in 4, with short-duration, low-amplitude motor unit potentials and small polyphasic potentials. Nerve conduction studies done in 7 patients showed decreased compound muscle action potentials in 4, normal findings in 2, a compressive neuropathy in 1, and a demyelinating polyneuropathy in 1. Serum creatine kinase was elevated to 2 to 100 times the upper limit of normal in 3. A histological diagnosis of acute quadriplegic myopathy was made in all 3 patients with muscle biopsy. Three died; and in survivors, weakness persisted for 3 to 12 months after discharge. [1]

COMMENT. The incidence of neuromuscular weakness in critically ill children in an ICU is infrequent and develops mainly in older children, over 10 years of age, and especially in transplant recipients.