CURRENT Essentials of Critical Care.pdf

Chapter 13 Neurology 195■■■Muscular DystrophyEssentials of Diagnosis• Progressive muscle wasting and weakness• Typically proximal muscle involvement; pseudohypertrophy ofgastrocnemius muscle• Mental impairment common in Duchenne muscular dystrophy• Elevated creatine kinase• Characteristic electromyogram and electrocardiogram: tall rightprecordial R wave and precordial Q waves• Muscle biopsy: fiber necrosis, size variation, infiltration by macrophages;replacement by connective tissue and fat• Pulmonary complications include respiratory insufficiency andinfection; cardiac complications include cardiomyopathy andconduction system abnormalities• Inherited myogenic disorders: congenital, Duchenne andBecker, Emery-Dreifuss, distal, facioscapulohumeral, oculopharyngeal• Increase rate of adverse events to anestheticsDifferential Diagnosis• Dermatopolymyositis • Botulism• Myasthenia gravis • Guillain-Barré syndrome• Amyotrophic lateral sclerosis • Lambert-Eaton syndromeTreatment• No proven treatment currently available• Monitor and manage complications• Consider noninvasive ventilatory support for respiratory insufficiency;elective intubation if vital capacity 15– 20 mL/kg;tracheostomy for prolonged support• Cardiomyopathy treated with standard medications; pacemakeror defibrillator for conduction system defects and arrhythmias■ PearlBecause of the risk of rhabdomyolysis, myoglobinuria, accelerationof muscle weakness, and hyperkalemic cardiac arrest, avoid succinylcholinein patients with Duchenne or Becker muscular dystrophy.ReferenceEmery AE: The muscular dystrophies. Lancet 2002;359:687. [PMID:11879882]