Amyotrophic lateral sclerosis (ALS) is a disease of the nervous system. It leads to damage of nerve cells in the brain and spine. These nerves control muscle movement. The related muscles weaken and shrink as the disease progresses. Changes to the nerves and muscles get worse over time.
The Nervous System
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The cause of ALS is unknown. Changes in certain genes may play a role. More than a dozen genetic changes have been linked to ALS. More research will help to understand how they work in the development of ALS. Other factors like smoking or exposure to toxins may also play a role. The link to these factors is not clear.
Factors that may increase your chance of ALS include:
Military veterans have twice the risk of ALS. It is not clear why.
The first signs of ALS are minor. They may be overlooked. Symptoms can differ from person to person but may include:
Symptoms will worsen over time. How fast it changes will vary from person to person. Symptoms may progress to:
You will be asked about your symptoms and health history. A physical exam will be done. There are no specific tests to diagnose ALS. Symptoms will point to a problem with the nervous system. Tests will then be done to rule out other health issues that cause similar problems. Your doctor or specialists may ask for:
The care team will look at the results of all the tests and types of symptoms. This will be used to diagnose ALS. However, there are other diseases with similar symptoms at start of disease. A second opinion with a nerve specialist may help to confirm the diagnosis.
There is currently no cure for ALS. A combination of treatments may help to reduce or manage symptoms. Treatment options include:
Some medicines may help to slow the progression of ALS. The medicine may be given daily or in cycles. They may also only be useful at certain stages.
Medicine may also be used to:
Palliative care is a team of experts that help those with severe illnesses. They can help guide overall care according to your wishes. The team will focus on quality of life for you and your family.
ALS will affect muscles throughout the body. Chewing, swallowing, speech, and breathing can all be affected. Care will help to support the body when these changes occur. Help may include:
There are no current guidelines to prevent ALS.
National Institute of Neurological Disorders and Stroke
Amyotrophic Lateral Sclerosis Society of British Columbia
Amyotrophic lateral sclerosis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/amyotrophic-lateral-sclerosis-als . Updated September 13, 2018. Accessed September 5, 2019.
Amyotrophic lateral sclerosis (ALS) fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Amyotrophic-Lateral-Sclerosis-ALS-Fact-Sheet#Causes. Updated August 13, 2019. Accessed September 5, 2019.
Kiernan MC, Vucic S, Cheah BC, et al. Amyotrophic lateral sclerosis. Lancet. 2011 Mar 12;377(9769):942-55
What is ALS? ALS Association website. Available at:
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Accessed September 5, 2019.
9/3/2014 DynaMed Plus Systematic Literature Surveillance. Available at:
http://www.dynamed.com/topics/dmp~AN~T116744/Amyotrophic-lateral-sclerosis-ALS: Wippold FJ, Cornelius RS, Broderick DF, et al. American College of Radiology (ACR) Appropriateness Criteria for dementia and movement disorders. Available at:
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Updated 2014. Accessed February 12, 2016.
9/26/2017 DynaMed Plus Systematic Literature Surveillance. Available at: http://www.dynamed.com/topics/dmp~AN~T116744/Amyotrophic-lateral-sclerosis-ALS : US Food and Drug Administration. FDA approves drug to treat ALS. Available at: https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm557102.htm. Published May 5, 2017. Accessed September 26, 2017.
Last reviewed March 2019 by
EBSCO Medical Review Board
Rimas Lukas, MD
Last Updated: 9/5/2019