CLINICAL AND LABORATORY OBSERVATIONS Critical illness neuromuscular disease in children manifested as ventilatory dependence Raj D. Sheth, MD, William E. M. Pryse-Phillips, MD, Jack E. Riggs, MD, and John B. Bodensteiner, MD From the Departments of Neurology and Pediatrics, West Virginia University Health Sciences Center, Morgantown, and the Department of Medicine (Neurology), Memorial University of Newfoundland, St. John's, Canada Four children with prolonged dependency on a ventilator were found to have reversible quadriparesis, muscle wasting, and hyporeflexia after 8 to 20 days of assisted ventilation for life-threatening sepsis or respiratory failure. Critical illness neuromuscular disease, which was recently recognized as a distinct clin- ical syndrome in adults, may also be manifested in children by prolonged ven- tilatory dependency. (J PEDIATR 1995;126:259-61) Prolonged dependence on a ventilator occurs in 30% of adults recovering from sepsis and multiple organ failure 1 and was initially attributed to nutritional or steroid myop- athy, toxic effects of gentamicin or pancuronium bromide, acute inflammatory demyelinating polyneuropathy, or pan- creatic dysfunction. 2 Subsequently a distinctive syndrome involving an underlying polyneuropathy or myopathy was identified, 3 which is herein referred to as critical illness neuromuscular disease. Similar problems have not been well characterized in children. METHODS The medical records of all patients who underwent elec- trophysiologic studies for failure to be weaned from venti- latory support in a tertiary care pediatric intensive care unit during a 6-year period were reviewed. Many patients had difficulty being weaned from ventilatory support during this period, but only four patients had electrophysiologic studies. CASE REPORTS Patient 1. A 15-year-old girl had septic shock as a result of group C Neisseria meningitidis, and she had associated bilateral adrenal hemorrhages. Two days later acute kidney failure necessitated peritoneal dialysis for 72 hours. Medications administered included midazolam, cefotaxime, dopamine, and methylprednisolone. In- termittent doses of vecuronium, 0.03 mg/kg, provided neuromus- cular blockade for 48 hours. Although the patient's mental status Submitted for publication July 20, 1994; accepted Sept. 6, 1994. Reprint requests: Raj D. Sheth, MD, West Virginia University Health Science Center, Box 9180, Morgantown, WV 26506-9180. Copyright © 1995 by Mosby-Year Book, Inc. 0022-3476/95/$3.00 + 0 9/22/60449 returned to normal, she could not undergo extubation until 6 days after vecuronium was discontinued because she had profound hyporeflexic muscle weakness. Serum creatine kinase activity (116 mmol/L) and results of cerebrospinal fluid analysis (protein, 0.39 gm/L; no cells) were normal. Electrophysiologic studies on day 8 demonstrated small compound muscle action potentials over the abductor pollicis brevis muscle. Median and peroneal motor nerve conduction velocities were normal. Electromyogra- phy of the deltoid muscle demonstrated a poor recruitment pattern. Additional electromyography on day 16 demonstrated promi- nent fibrillations in the first dorsal interosseous muscle with a slight excess of polyphasic units of increased duration. The pa- tient's strength returned to normal 6 weeks after the onset of ill- ness. Patient 2. A 15-year-old boy with septic shock as a result of group B N. meningitidis required vigorous fluid resuscitation and venti- latory support. He received ampicillin, chloramphenicol, midazo- lam, dopamine, and methylprednisolone. Intermittent doses of vecuronium, 0.04 mg/kg, provided neuromuscular blockade for 5 days. The patient's mental status was normal when vecuronium was discontinued. An extubation attempt on day 8 was unsuccessful because of severe quadriparesis. Diffuse muscle atrophy was present, and muscle stretch reflexes were absent. Serum creatine kinase activity (116 mmol/L) and results of cerebrospinal fluid analysis (protein, 0.29 gm/L; no cells) were normal. Cranial com- puted tomography and abdominal ultrasonography findings were normal. Three days later a second attempt at extubation was suc- cessful. A gradual return to normal muscle strength occurred dur- ing the next 3 months, although hyporeflexia remained. Seventeen months later, the patient's reflexes were normal. At that time, mo- tor nerve conduction velocities were normal in the median and common peroneal nerves, although compound muscle action po- tentials were dispersed. Electromyography demonstrated motor unit potential amplitudes to 11 mV in the tibialis anterior, vastus lateralis, and extensor digitorum communis muscles, suggesting 259