AANN Core Curriculum, 7th Edition, Ch. 16 Neuromuscular Disorders: Digital Version-Chapter 16

Chapter 16

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This chapter reviews neuromuscular disorders affecting peripheral nerves, the neuromuscular junction, and muscle. They may cause weakness, sensory changes, pain, impaired mobility, swallowing or communication problems, and respiratory failure. Many are immune-mediated or genetic; others result from diabetes, toxins, metabolic dysfunction, or anesthesia-related triggers.<br /><br />Peripheral nerve disorders include Guillain–Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy, diabetic and toxic neuropathies, and hereditary neuropathies such as Charcot–Marie–Tooth disease. GBS typically causes rapidly ascending, symmetrical weakness and reduced reflexes, sometimes with pain, autonomic dysfunction, and respiratory compromise. Early respiratory monitoring is essential: forced vital capacity is the best measure, while oxygen saturation and blood-gas changes may be late signs. Treatments include IV immunoglobulin or plasma exchange; corticosteroids are not beneficial.<br /><br />Neuromuscular-junction disorders include myasthenia gravis (MG) and Lambert–Eaton syndrome. MG causes fluctuating, fatigable weakness that can affect eye, bulbar, limb, and respiratory muscles. Respiratory assessment includes vital capacity, breathing effort, cough and swallowing strength, orthopnea, and ability to count in one breath. Treatment may include pyridostigmine, immunosuppression, IVIG or plasma exchange for exacerbations, and thymectomy in selected patients. Lambert–Eaton syndrome is often associated with small-cell lung cancer and may improve briefly after exercise.<br /><br />Muscle disorders include inflammatory and congenital myopathies, metabolic myopathies, channelopathies, muscular dystrophies, and amyotrophic lateral sclerosis (ALS). Management varies, but often combines rehabilitation, symptom control, respiratory and cardiac surveillance, and multidisciplinary care. Genetic testing and counseling are important for inherited disorders. Some conditions have targeted treatments, including enzyme replacement for Pompe disease and exon-skipping therapy for eligible Duchenne muscular dystrophy.<br /><br />ALS damages upper and lower motor neurons, causing progressive weakness, atrophy, fasciculations, and sometimes bulbar or cognitive symptoms. Warning signs of respiratory decline include dyspnea, orthopnea, daytime sleepiness, morning headaches, rising carbon dioxide, falling vital capacity, accessory-muscle use, and difficulty clearing secretions. Noninvasive ventilation, cough assistance, nutritional support, communication aids, and advance-care planning are important. Riluzole and edaravone can modestly slow progression.

Keywords

neuromuscular disorders

peripheral neuropathy

Guillain-Barre syndrome

myasthenia gravis

Lambert-Eaton syndrome

muscular dystrophy

amyotrophic lateral sclerosis

respiratory failure

immunoglobulin therapy

forced vital capacity