Amyotrophic lateral sclerosis (ALS) is a nervous system disorder that worsens over time. It affects nerves in the brain and spine that are responsible for muscle movement. The nerves gradually die, which can lead to almost total paralysis, including being unable to breathe. ALS is fatal, often due to respiratory failure.

The Nervous System

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The cause of ALS is unknown. Genes may play a role.

The symptoms of ALS are caused by the death of the nerves. If the nerves can't send signals to the muscle, then they are unable to work. Overtime, the muscles become weak and shrink from lack of use.

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 as the general population. It is not clear why.


The first signs of ALS are subtle and can be different from person to person. They may include:

  • Changes in how you speak
  • Frequent tripping while walking or general clumsiness
  • Trouble with fine motor tasks like grasping a pen

The speed of the progression can be very different between people. As the disease progresses it can lead to:

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


You will be asked about your symptoms and medical history. A physical exam will be done. There are no tests that can specifically diagnose ALS. Instead, tests will be done to rule out other medical conditions.

Imaging tests to look for changes in the brain or spine may include:

Other tests may include:

  • Blood tests—to look for infections or metabolic change
  • Lumbar puncture—to look for changes in the fluid that surrounds the brain and spinal cord
  • Biopsy to evaluate tissue under a microscope

Your muscles and nerves may also be checked. This can be done with electromyogram (EMG)/nerve conduction velocities (NCV).

Your thinking and processing skills may also be checked.


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

The drug riluzole and edaravone have been approved for ALS. The drugs may slightly improve functioning, but it does not stop the disease from progressing.

Medications may include:

  • Muscle relaxants to help muscles that are in spasm
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) and other pain medications
  • Medication to reduce heavy drooling
  • Antidepressants and anti-anxiety drugs
  • Medication to treat inappropriate laughter or crying

Supportive care may be needed as ALS progresses, including:

  • Physical therapy—To reduce pain associated with muscle cramping and spasticity
  • Respiratory care—In some cases, extra oxygen may be needed or a machine may be needed to help with breathing. Surgery will be eventually needed to make an artificial airway that bypasses the throat.
  • Nutritional care—Swallowing will eventually be lost. Nutrition will need to be delivered through a feeding tube.
  • Speech therapy—Speech therapy may help improve communication. This will not only include working with speech when possible, but also finding other ways to communicate when speech is no longer possible.
  • Seeking mental health counseling and joining a support group


There are no current guidelines to prevent ALS because the cause is unknown.