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Amyotrophic Lateral Sclerosis Overview.


GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2019.
2001 Mar 23 [updated 2015 Feb 12].

Author information

Division of Neuromuscular Medicine, Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois
Division of Neuromuscular Medicine, Davee Department of Neurology and Clinical Neurosciences and the Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois



Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease involving both upper motor neurons (UMN) and lower motor neurons (LMN). UMN signs include hyperreflexia, extensor plantar response, increased muscle tone, and weakness in a topographic representation. LMN signs include weakness, muscle wasting, hyporeflexia, muscle cramps, and fasciculations. Initial presentation varies. Affected individuals typically present with either asymmetric focal weakness of the extremities (stumbling or poor handgrip) or bulbar findings (dysarthria, dysphagia). Other findings may include muscle fasciculations, muscle cramps, and labile affect, but not necessarily mood. Regardless of initial symptoms, atrophy and weakness eventually affect other muscles. The mean age of onset is 56 years in individuals with no known family history and 46 years in individuals with more than one affected family member (familial ALS or FALS). Average disease duration is about three years, but it can vary significantly. Death usually results from compromise of the respiratory muscles.


The diagnosis of ALS is based on clinical features, electrodiagnostic testing, and exclusion of other health conditions with related symptoms. Molecular genetic testing plays a prominent role in diagnosis of the genetic subtype and genetic counseling.


Amyotrophic lateral sclerosis can be inherited in an autosomal dominant, autosomal recessive, or X-linked manner. Genetic counseling and risk assessment depend on accurate determination of the specific genetic diagnosis.


Treatment of manifestations: Treatment is palliative. Individuals with ALS may benefit from care by a multidisciplinary team that includes a neurologist, specially trained nurses, pulmonologist, speech therapist, physical therapist, occupational therapist, respiratory therapist, nutritionist, psychologist, social worker, and genetics professional. Riluzole is the only currently FDA-approved drug for treatment of ALS. Oral secretions in those with bulbar symptoms can be reduced with tricylic antidepressants and other anticholinergic agents. Pseudobulbar affect can be managed with antidepressants. Swallowing difficulties can be alleviated by thickening liquids and pureeing solid food and, eventually, by use of a gastrostomy tube to help maintain caloric intake and hydration. Medications such as baclofen and benzodiazepines can help relieve spasticity and muscle cramps. Alphabet boards and computer-assisted devices can aid communication. Other assistive devices such as walkers, wheelchairs, bathroom modifications, hospital beds, and Hoyer lifts can aid in activities of daily life. Ventilatory assistance may include BIPAP and/or mechanical ventilation. Hospice care in terminal stages is beneficial.

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