Definition

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 Copyright © Nucleus Medical Media, Inc.

Causes

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.

Risk Factors

Factors that may increase your chance of ALS include:

• Having a family member with ALS
• Having certain genetic mutations

Military veterans have twice the risk of ALS. It is not clear why.

Symptoms

The first signs of ALS are minor. They may be overlooked. Symptoms can differ from person to person but may include:

• Changes in speech
• Tripping often while walking; general clumsiness
• Trouble with skilled movements like grasping a pen

Symptoms will worsen over time. How fast it changes will vary from person to person. Symptoms may progress to:

• Increasing weakness in arms and legs
• Wrist or foot drop
• Trouble holding things
• Muscle twitching
• Unpredictable and changing emotions
• Slurred speech— dysarthria
• Hoarseness and coughing
• Trouble chewing and swallowing—may show as choking and gagging often
• Weight loss due to trouble eating
• Trouble breathing
• Excess salivation, drooling

Diagnosis

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:

• Family history
• Imaging tests of brain and spine with:
  • MRI scan
  • CT scan
• 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.

Treatment

There is currently no cure for ALS. A combination of treatments may help to reduce or manage symptoms. Treatment options include:

Prevention

There are no current guidelines to prevent ALS.