Amyotrophic Lateral Sclerosis (ALS)


What Is It?

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a slowly progressive degeneration of nerve cells of the spinal cord, brain and brain stem, the bottom portion of the brain near the spinal cord. This degeneration affects only nerve cells that control muscle movements (motor neurons), resulting in the gradual loss of a person’s ability to control his or her muscles. This disease does not affect mental abilities or nerves that control the senses.

Although the cause of ALS remains unknown, current theories suggest that certain chemicals, including one that transmits signals between nerve cells, may play some role in the death of motor nerve cells. ALS generally strikes patients between the ages of 50 and 70, and affects men slightly more often than women. About 5 percent to 10 percent of cases appear to be inherited.


Symptoms of ALS include:

  • Slow, but relentlessly progressive, muscle weakness and wasting (atrophy) in the arms and legs, torso, breathing muscles, throat and tongue. Weakness usually begins in the arms and legs.
  • Muscle twitching, cramps, stiffness, and muscles that fatigue easily
  • Slowed speech that becomes progressively harder to understand
  • Difficulty breathing and swallowing; choking
  • Weight loss because of both muscle atrophy and poor nutrition caused by problems swallowing
  • Sudden involuntary bursts of laughter or crying
  • Changes in the way the person walks, progressing to an inability to walk


Your doctor will ask about your medical history and will perform a physical examination, include a neurological examination to look for the following signs:

  • A localized loss of muscle bulk (focal muscle wasting)
  • Muscle twitching
  • Muscle weakness in your arms and legs
  • Spasticity, in which the arms or legs resist being moved by someone else.
  • Abnormal tendon reflexes
  • The Babinski sign, in which the toe moves upward when the sole of the foot is stroked
  • Breathing problems that severely limit normal air exchange in the lungs
  • Facial weakness
  • Slurred speech

The physician also checks to see whether sensation, eye movement, and higher thought processes, such as perception, reasoning, judgment and imagination, have been affected, because they remain intact in people with ALS.

Your doctor will diagnose ALS based on the signs and symptoms he or she sees during your examination, and by excluding other causes of progressive movement problems. To confirm the diagnosis, your doctor also may order other tests such as electromyography (EMG) or magnetic resonance imaging (MRI) scans. In some cases, EMG and MRI scans may be performed to rule out other possible causes of symptoms.

Expected Duration

People with ALS generally live an average of three to five years after the symptoms begin. Most die from an inability to breathe or from lung infections that tend to occur when breathing is impaired for long periods of time.


There is no known way to prevent ALS.


Although there is no cure for ALS, new treatments are becoming available. Right now, Riluzole (Rilutek) is the only drug approved by the U.S. Food and Drug Administration for ALS, and it has a modest effect in prolonging survival. Other treatments under study include a variety of growth factors that might stimulate nerve recovery, medicines that alter the immune system, and topiramate (Topamax), a drug that controls seizures. Animal studies have raised hopes about other therapies that might improve nerve and muscle function in people with ALS. These therapies include creatine, vitamin E, and the use of stem cells to replace failing cells in the body. Many active clinical trials offer patients the chance to participate in the development of new therapies.

To help manage the symptoms of ALS, mechanical devices, such as dressing aids and special utensils for eating, are available to make self-care easier. A cane or walker also may be helpful for patients who have difficulty walking. Patients should consider the option of using a mechanical respirator if they become unable to breathe on their own. Although artificial ventilation can help some patients survive for years, many patients choose not to be kept alive in a state of total paralysis, unable to communicate except with eye movements. Patients with ALS should discuss this issue with their doctors early in the illness, so that the important and difficult decisions about emergency resuscitation can be made according to the patient’s wishes in the event of life-threatening breathing problems.

Emotional support is crucial. Although much of this support can be provided by the patient’s friends and family, a qualified counselor or psychotherapist also can be a valuable asset.

When To Call A Professional

See your doctor as soon as possible whenever you develop unexplained muscle weakness or difficulty controlling movement. This is especially important if speaking, breathing or swallowing seems to be affected.


ALS eventually leads to death as muscles governing breathing, swallowing and other crucial body functions are affected. However, since active research continues into the causes and treatment of ALS, ALS patients and their families should never give up hope.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.