Health Encyclopedia:


Amyotrophic Lateral Sclerosis (ALS)

What is ALS?

Amyotrophic lateral sclerosis is a fatal neurological disorder characterized by progressive degeneration of nerve cells in the spinal cord and brain. It is often referred to as Lou Gehrig's disease, (after a famous baseball player who died from the disease. ALS it is one of the most devastating of the disorders that affects the function of nerves and muscles.

ALS does not affect mental functioning or the senses (such as seeing or hearing), and it is not contagious. Currently, there is no cure for this disease.

ALS most commonly affects people of any racial or ethnic group between the ages of 40 and 70, although it can occur at a younger age.

There are 2 main classifications of ALS:

  • Sporadic. The most common form of ALS in the U.S., making up 90% to 95% of all cases. These cases occur randomly, without any known cause, and there is no family history of ALS .
  • Familial. This form of ALS affects a small amount of people and is thought to be inherited.

What causes ALS?

Experts do not know the cause of ALS. In a very small percentage of cases, genetics is involved. ALS. Research is looking into possible environmental causes of ALS.

What are the symptoms of ALS?

With ALS, you may first have weakness in one limb that develops over a matter of days or, more commonly, a few weeks. Then, several weeks to months later, weakness develops in another limb. Sometimes the initial problem can be one of slurred speech or difficulty swallowing.

As ALS progresses, though, more and more symptoms are noticed. The following are the most common symptoms of ALS. However, each individual may experience symptoms differently. Symptoms may include:

  • Twitching and cramping of muscles, especially those in the hands and feet
  • Loss of motor control in the hands and arms
  • Impairment in the use of the arms and legs
  • Tripping and falling
  • Dropping things
  • Persistent fatigue
  • Uncontrollable periods of laughing or crying
  • Slurred or thick speech and difficulty in projecting the voice

As the disease progresses, symptoms may include:

  • Difficulty breathing
  • Difficulty swallowing
  • Paralysis

The symptoms of ALS may resemble other conditions or medical problems. Always consult your health care provider for a diagnosis.

How is ALS diagnosed?

There is no specific test to diagnose ALS. Your health care provider will consider your medical history and symptoms and will do certain tests to rule out other conditions including:

  • Lab tests. These include blood and urine studies and thyroid functioning tests
  • Muscle and/or nerve biopsy. In this procedure, sample of tissue or cells are removed from the body for examination under a microscope
  • Spinal tap (also called a lumbar puncture). In this test, a special needle is placed into the lower back, into the area around the spinal cord. The pressure in the spinal canal and brain can then be measured. A small amount of cerebral spinal fluid (CSF) can be removed and sent for testing to determine if there is an infection or other problems. CSF is the fluid that bathes the brain and spinal cord.


  • X-ray. This diagnostic test uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film
  • Magnetic resonance imaging (MRI). This diagnostic procedure  uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body
  • Electrodiagnostic tests, such as electromyography (EMG) and nerve conduction study (NCS). These studies evaluate and diagnose disorders of the muscles and motor neurons. Electrodes are inserted into the muscle, or placed on the skin overlying a muscle or muscle group, and electrical activity and muscle response are recorded.

What are the complications of ALS?

There is no cure for ALS. Over a period of 3 to 5 years, the disease will progress, making voluntary movements of arms and legs impossible, requiring assistance with personal care, eating, and mobility. Movement of the diaphragm for breathing is also impaired and a ventilator may be required for breathing. Most individuals with ALS die from respiratory failure.

How is ALS treated?

Your specific treatment plan will be determined by your health care provider based on:

  • Your age, overall health, and medical history
  • Extent of the disease
  • Your tolerance for specific medications, procedures, or therapies
  • Expectations for the course of the disease
  • Your opinion or preference

For most people with ALS, primary treatment may involve the management of symptoms, and may include physical, occupational, speech, respiratory, and nutritional therapies. Some medications and/or heat or whirlpool therapy may help to relieve muscle cramping. Exercise, in moderation, may help to maintain muscle strength and function.

There is no cure and no proven treatment for ALS. However, the FDA approved riluzole (Rilutek), the first drug that has prolonged the survival of persons with ALS.

Managing the symptoms of ALS is a process that is challenging for you, your caregivers, and your medical team. However, it’s important to know that there are many community resources available for support and assistance.

Researchers are conducting studies to increase their understanding of genes that may cause the disease, mechanisms that can trigger motor neurons to degenerate in ALS, and approaches to stop the progress leading to cell death.

Living with ALS

ALS will eventually lead to disability and death. Although your ability to move and breathe independently will be affected, your intelligence and ability to think is not. You and your family will work closely with your health care provider to manage symptoms as they develop. Use of the medication Rilutek may prolong your life by a few months, particularly for if you have swallowing difficulty. Discuss ways to make living spaces more accessible, use of mobility devices and wheelchairs. It’s very important to discuss end-of-life decisions with your loved ones.

When should I call my health care provider?

It is important that you keep your health care provider informed about new symptoms so she or he can recommend therapies and community resources appropriately. Most importantly, call your health care provider if you begin to have difficulty breathing.

Key points

  • ALS is a terminal neurological disorder characterized by progressive degeneration of nerve cells in the spinal cord and brain.
  • ALS affects voluntary control of arms and legs, and leads to respiratory difficulties.
  • ALS does not affect intelligence, thinking, seeing, or hearing.
  • There is no known cure for ALS.

Treatment of ALS focuses on managing or minimizing symptoms as much as possible.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.
Online Medical Reviewer: Fraser, Marianne, MSN, RN
Online Medical Reviewer: Sohrabi, Farrokh, MD
Last Review Date: 1/13/2014
© 2000-2015 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.