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 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.
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:
Blood tests—to look for infections or other changes
Lumbar puncture—to look for changes in the fluid that surrounds the brain and spinal cord
Biopsy to closely examine muscle and nerve tissue under a microscope
Electromyogram—to look at problems with connection between nerve and muscle
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.
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: ...(Click grey area to select URL) Accessed September 5, 2019.