AMYOTROPHIC LATERAL SCLEROSIS

DEFINITION

Amyotrophic lateral sclerosis (ALS; pronounced ay-MY-eh-TRO-fik LA-ter-el skler-OH-sis) is a neurodegenerative disease. A neurodegenerative disease is one in which nerve cells are damaged or killed. In the case of ALS, the nerve cells that are damaged are motor neurons. Motor neurons are nerve cells that control movement. ALS is also known as motor neuron disease and Lou Gehrig's disease. Lou Gehrig (1903–41) was a famous baseball player who died of the disease.

DESCRIPTION

Under normal circumstances, muscles move because of messages sent from the brain through the spinal cord to the muscles. These messages are carried by motor neurons. In ALS, those motor neurons die off and messages from the brain to the muscles do not flow normally. Muscles do not respond when they are supposed to or as well as they should.

The death of motor neurons affects voluntary muscles. These muscles are controlled by conscious thought. They include muscles in the legs, arms, and trunk. These muscles normally move when a person wants them to move. As ALS develops, a person loses that control over these muscles.

ALS normally does not affect other kinds of muscles, such as those in the heart or digestive system. It also has no effect on the brain. Thus, ALS patients can usually think normally, although they lose the ability to move.

ALS affects approximately thirty thousand people in the United States. About five thousand new cases are diagnosed each year. Most cases occur in people between the age of forty and seventy. Men are slightly more likely to develop ALS than women.

ALS usually progresses slowly. In about half of all patients, it causes death within three years. About 80 percent of all patients die in less than five years, and a small number (about 10 percent) survive more than eight years.

CAUSES

No one knows what causes ALS. One or more factors cause motor neurons in the brain

ALS is also known as Lou Gehrig's disease, after the famous baseball player who died of the disease in 1941. (Reproduced by permission of

Archive Photos

)

and spinal cord to begin dying off. Nerve signals can no longer travel from the brain to the muscles. The patient is unable to move normally and he or she becomes weaker. Disturbed nerve messages can cause abnormal muscle movements that result in twitching and spasms. As muscle cells are not used, they begin to die off. The amount of muscle tissue decreases, causing a condition known as wasting.

Researchers have been unsuccessful in finding the cause of motor neuron death. There is some evidence that free radicals may be involved. Free radicals are very active chemicals that can damage living cells. Defective enzymes may also be a factor in the death of motor neurons. An enzyme is a naturally occurring chemical needed for many chemical reactions that occur in the body. Additional research is now being conducted to find out more about the cause or causes of ALS.

Two major forms of ALS are known: familial and sporadic. About 10 percent of all ALS cases are familial. As the name suggests, familial ALS is thought to be caused by genetic factors. Scientists have found that 15 percent of the people with familial ALS have a mutation (change) in a gene known as SOD-1. A parent with this mutated gene can pass it on to his or her children.

Sporadic ALS has no known cause. Certain chemical factors in the body, such as free radicals, may be involved. Or it, too, may result from genetic factors.

SYMPTOMS

The earliest sign of ALS is usually weakness in the arms or legs. This weakness tends to be more apparent on one side of the body than the other. Leg weakness may first become apparent by an increased frequency of stumbling on uneven pavement or difficulty in climbing stairs. Arm weakness may lead to difficulty in grasping or holding a cup, for instance, or loss of coordination in fingers.

Less commonly, the earliest sign of ALS is weakness in muscles of the mouth. This condition makes it difficult for the patient to chew, swallow and speak. He or she may become hoarse or tired after speaking or may have slurred speech.

Over time, ALS spreads to all voluntary muscle groups in the body. Later symptoms include loss of the ability to walk, to use the arms and hands, to speak clearly or at all, to swallow, and to hold up one's head. Weakness in the muscles of the respiratory (breathing) system can make breathing, coughing, and swallowing difficult. These conditions can result in the inhaling of foods or saliva (aspiration) which, in turn, can cause lung infections. Such infections are a common cause of death in ALS patients.

Respiratory problems can be reduced by inserting a mechanical ventilator in the person's throat. This breathing device can extend the patient's life, although muscle weakness and wasting are not reduced. Toward the end of the disease, ALS patients may be able to communicate only by means of eye blinks or a computer-assisted device.

DIAGNOSIS

The diagnosis of ALS begins with a complete medical history, physical examination, and neurological (nervous system) examination. An electromyogram (EMG; pronounced ih-LECK-tro-my-oh-gram) is part of the neurological exam. An EMG measures muscle function and tells how much damage has already occurred in motor neurons. A variety of blood and urine tests, X rays, and brain scans may also be conducted to rule out diseases other than ALS. ALS is rarely misdiagnosed after a review of all these factors.

TREATMENT

There is no cure for ALS. There are also no treatments that can significantly alter the course of the disease. In 1998 a new drug, riluzole (trade name Rilutek) was approved for use with ALS patients. The drug somewhat reduces the loss of muscle strength. It can extend the life of an ALS patient for an average of three months. No other drug or vitamin has been found to

Renowned scientist Stephen Hawking suffers from amyotrophic lateral sclerosis. (Reproduced by permission of

AP/Wide World Photos

)

have any effect on the progress of ALS.

Physical therapy can often help a patient maintain strength, retain range of motion, and promote general health. Stretching exercises and swimming are often a part of these routines. Drugs can sometimes be helpful in treating certain symptoms of ALS, such as cramping.

Various health specialists can be of help in dealing with specific problems encountered by ALS patients. An occupational therapist, for example, can help design solutions to the patient's movement and coordination problems. He or she can also help design special devices and home modifications to improve the patient's mobility.

Speech therapists can train an ALS patient to deal with problems of swallowing and speaking. A nutritionist can help patients design diets that will be easier to swallow and yet still be nutritious.

In later stages of the disease, mechanical ventilators may be necessary. Mechanical ventilators help patients to breathe more easily and can help prevent aspiration. They can be inserted through the mouth or nose or though an opening in the throat. Modern mechanical ventilators are small and portable. They allow ALS patients some degree of freedom and mobility. Under the best of circumstances, ventilators are somewhat awkward and unpleasant devices. Some ALS patients choose to use them for only short periods of time or not at all.

Most ALS patients eventually require full-time nursing care. This care is not difficult to learn and can often be provided by family members. The physical and emotional burden for caregivers, however, can be enormous. They must learn to be aware of and to find ways of dealing with their own needs as well as those of the patient.

Support groups can help caregivers in this regard. Support groups consist of other people also working with ALS patients as well as professional counselors. Support groups are sponsored by both the ALS Society and the Muscular Dystrophy Association.

Alternative Treatment

There is no scientific evidence that any form of alternative therapy has been successful in treating ALS. A number of vitamins, herbal remedies, and other natural products have been tried but, thus far, none appears to have any success. As the causes of the disease are better understood, it is possible that some alterative therapies may be found to provide relief from the disease.

PROGNOSIS

ALS usually progresses rapidly and leads to death from respiratory infection within three to five years. The disease progresses most slowly in those who are young and have their first symptoms in the arms and legs.

PREVENTION

There is no known way to prevent ALS or to alter its course.

FOR MORE INFORMATION

Books

Atkinson, David R., and Debbie Atkinson. Hope Springs Eternal: Surviving a Chronic Disease. Virginia Beach, VA: Are Press, 1999.

Horn, Robert, III. How Will They Know If I'm Dead?: Transcending Disability and Terminal Illness. Boca Raton, FL: Saint Lucie Press, 1996.

The Muscular Dystrophy Association. When a Loved One Has ALS: A Care-giver's Guide. Tucson, AZ: The Muscular Dystrophy Association, 1997.

Schwartz, Morrie. Letting Go: Morrie's Reflections on Living While Dying. New York: Dell Books, 1997.

Organizations

The ALS Association. 27001 Agoura Road, Suite 150, Calabasas Hills, CA 91301–5104. (800) 782–4747. http://www.alsa.org.

The Muscular Dystrophy Association. 3300 East Sunrise Drive, Tucson, AZ 85718. (520) 529–2000; (800) 572–1717. http://www.mdausa.org.

Web sites

"Amyotrophic Lateral Sclerosis (ALS)." National Institute of Neurological Disorders and Stroke. [Online] http://www.ninds.nih.gov (accessed on June 15, 1999).