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amyotrophic lateral sclerosis

 
Medical Encyclopedia: Amyotrophic Lateral Sclerosis

Definition

Amyotrophic lateral sclerosis (ALS) is a disease that breaks down tissues in the nervous system (a neurodegenerative disease) of unknown cause that affects the nerves responsible for movement. It is also known as motor neuron disease and Lou Gehrig's disease, after the baseball player whose career it ended.

Description

ALS is a disease of the motor neurons, those nerve cells reaching from the brain to the spinal cord (upper motor neurons) and the spinal cord to the peripheral nerves (lower motor neurons) that control muscle movement. In ALS, for unknown reasons, these neurons die, leading to a progressive loss of the ability to move virtually any of the muscles in the body. ALS affects "voluntary" muscles, those controlled by conscious thought, such as the arm, leg, and trunk muscles. ALS, in and of itself, does not affect sensation, thought processes, the heart muscle, or the "smooth" muscle of the digestive system, bladder, and other internal organs. Most people with ALS retain function of their eye muscles as well. However, various forms of ALS may be associated with a loss of intellectual function (dementia) or sensory symptoms.

"Amyotrophic" refers to the loss of muscle bulk, a cardinal sign of ALS. "Lateral" indicates one of the regions of the spinal cord affected, and "sclerosis" describes the hardened tissue that develops in place of healthy nerves. ALS affects approximately 30, 000 people in the United States, with about 5, 000 new cases each year. It usually begins between the ages of 40 and 70, although younger onset is possible. Men are slightly more likely to develop ALS than women.

ALS progresses rapidly in most cases. It is fatal within three years for 50% of all people affected, and within five years for 80%. Ten percent of people with ALS live beyond eight years.

— L. Fleming Fallon, Jr., MD, DrPH



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Dictionary: a·my·o·tro·phic lateral sclerosis   (ā'mī-ə-trō'fĭk, -trŏf'ĭk, ā-mī'-) pronunciation
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n. (Abbr. ALS)
A chronic, progressive disease marked by gradual degeneration of the nerve cells in the central nervous system that control voluntary muscle movement. The disorder causes muscle weakness and atrophy and usually results in death. Also called Lou Gehrig's disease.


Britannica Concise Encyclopedia: amyotrophic lateral sclerosis
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Degenerative nervous-system disorder causing muscle wasting and paralysis. The disease usually occurs after age 40, more often in men. Most victims die within two to five years from respiratory muscle atrophy. ALS affects motor neurons; the muscles they control become weak and atrophied, with debility usually beginning in the hands and creeping slowly up to the shoulders. The lower limbs become weak and spastic. Variants include progressive muscular atrophy and progressive bulbar palsy. In 1993 the defective gene that accounts for 5 – 10% of cases was discovered; it produces an ineffective version of an enzyme that neutralizes free radicals, which destroy motor neurons.

For more information on amyotrophic lateral sclerosis, visit Britannica.com.

Neurological Disorder:

Amyotrophic lateral sclerosis

Top

Definition

Amyotrophic lateral sclerosis (ALS) is a disease that breaks down tissues in the nervous system (a neurodegenerative disease) of unknown cause that affects the nerves responsible for movement. It is also known as motor neuron disease and Lou Gehrig's disease, after the baseball player whose career it ended.

Description

ALS is a disease of the motor neurons, those nerve cells reaching from the brain to the spinal cord (upper motor neurons) and the spinal cord to the peripheral nerves (lower motor neurons) that control muscle movement. In ALS, for unknown reasons, these neurons die, leading to a progressive loss of the ability to move virtually any of the muscles in the body. ALS affects "voluntary" muscles, those controlled by conscious thought, such as the arm, leg, and trunk muscles. ALS, in and of itself, does not affect sensation, thought processes, the heart muscle, or the "smooth" muscle of the digestive system, bladder, and other internal organs. Most people with ALS retain function of their eye muscles as well. However, various forms of ALS may be associated with a loss of intellectual function (dementia) or sensory symptoms.

"Amyotrophic" refers to the loss of muscle bulk, a cardinal sign of ALS. "Lateral" indicates one of the regions of the spinal cord affected, and "sclerosis" describes the hardened tissue that develops in place of healthy nerves. ALS affects approximately 30,000 people in the United States, with about 5,000 new cases each year. It usually begins between the ages of 40 and 70, although younger onset is possible. Men are slightly more likely to develop ALS than women.

ALS progresses rapidly in most cases. It is fatal within three years for 50% of all people affected, and within five years for 80%. Ten percent of people with ALS live beyond eight years.

Causes and symptoms

Causes

The symptoms of ALS are caused by the death of motor neurons in the spinal cord and brain. Normally, these neurons convey electrical messages from the brain to the muscles to stimulate movement in the arms, legs, trunk, neck, and head. As motor neurons die, the muscles they enervate cannot be moved as effectively, and weakness results. In addition, lack of stimulation leads to muscle wasting, or loss of bulk. Involvement of the upper motor neurons causes spasms and increased tone in the limbs, and abnormal reflexes. Involvement of the lower motor neurons causes muscle wasting and twitching (fasciculations).

Although many causes of motor neuron degeneration have been suggested for ALS, none has yet been proven responsible. Results of recent research have implicated toxic molecular fragments known as free radicals. Some evidence suggests that a cascade of events leads to excess free radical production inside motor neurons, leading to their death. Why free radicals should be produced in excess amounts is unclear, as is whether this excess is the cause or the effect of other degenerative processes. Additional agents within this toxic cascade may include excessive levels of a neurotransmitter known as glutamate, which may over-stimulate motor neurons, thereby increasing free-radical production, and a faulty detoxification enzyme known as SOD-1, for superoxide dismutase type 1. The actual pathway of destruction is not known, however, nor is the trigger for the rapid degeneration that marks ALS. Further research may show that other pathways are involved, perhaps ones even more important than this one. Autoimmune factors or premature aging may play some role, as could viral agents or environmental toxins.

Two major forms of ALS are known: familial and sporadic. Familial ALS accounts for about 10% of all ALS cases. As the name suggests, familial ALS is believed to be caused by the inheritance of one or more faulty genes. About 15% of families with this type of ALS have mutations in the gene for SOD-1. SOD-1 gene defects are dominant, meaning only one gene copy is needed to develop the disease. Therefore, a parent with the faulty gene has a 50% chance of passing the gene along to a child.

Sporadic ALS has no known cause. While many environmental toxins have been suggested as causes, to date no research has confirmed any of the candidates investigated, including aluminum and mercury and lead from dental fillings. As research progresses, it is likely that many cases of sporadic ALS will be shown to have a genetic basis as well.

A third type, called Western Pacific ALS, occurs in Guam and other Pacific islands. This form combines symptoms of both ALS and Parkinson's disease.

Symptoms

The earliest sign of ALS is most often weakness in the arms or legs, usually more pronounced on one side than the other at first. Loss of function is usually more rapid in the legs among people with familial ALS and in the arms among those with sporadic ALS. Leg weakness may first become apparent by an increased frequency of stumbling on uneven pavement, or an unexplained difficulty climbing stairs. Arm weakness may lead to difficulty grasping and holding a cup, for instance, or loss of dexterity in the fingers.

Less often, the earliest sign of ALS is weakness in the bulbar muscles, those muscles in the mouth and throat that control chewing, swallowing, and speaking. A person with bulbar weakness may become hoarse or tired after speaking at length, or speech may become slurred.

In addition to weakness, the other cardinal signs of ALS are muscle wasting and persistent twitching (fasciculation). These are usually seen after weakness becomes obvious. Fasciculation is quite common in people without the disease, and is virtually never the first sign of ALS.

While initial weakness may be limited to one region, ALS almost always progresses rapidly to involve virtually all the 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 the head up. Weakness of the respiratory muscles makes breathing and coughing difficult, and poor swallowing control increases the likelihood of inhaling food or saliva (aspiration). Aspiration increases the likelihood of lung infection, which is often the cause of death. With a ventilator and scrupulous bronchial hygiene, a person with ALS may live much longer than the average, although weakness and wasting will continue to erode any remaining functional abilities. Most people with ALS continue to retain function of the extraocular muscles that move their eyes, allowing some communication to take place with simple blinks or through use of a computer-assisted device.

Diagnosis

The diagnosis of ALS begins with a complete medical history and physical exam, plus a neurological examination to determine the distribution and extent of weakness. An electrical test of muscle function, called an electromyogram, or EMG, is an important part of the diagnostic process. Various other tests, including blood and urine tests, x rays, and CT scans, may be done to rule out other possible causes of the symptoms, such as tumors of the skull base or high cervical spinal cord, thyroid disease, spinal arthritis, lead poisoning, or severe vitamin deficiency. ALS is rarely misdiagnosed following a careful review of all these factors.

Treatment

There is no cure for ALS, and no treatment that can significantly alter its course. There are many things which can be done, however, to help maintain quality of life and to retain functional ability even in the face of progressive weakness.

As of early 1998, only one drug had been approved for treatment of ALS. Riluzole (Rilutek) appears to provide on average a three-month increase in life expectancy when taken regularly early in the disease, and shows a significant slowing of the loss of muscle strength. Riluzole acts by decreasing glutamate release from nerve terminals. Experimental trials of nerve growth factor have not demonstrated any benefit. No other drug or vitamin currently available has been shown to have any effect on the course of ALS.

A physical therapist works with an affected person and family to implement exercise and stretching programs to maintain strength and range of motion, and to promote general health. Swimming may be a good choice for people with ALS, as it provides a low-impact workout to most muscle groups. One result of chronic inactivity is contracture, or muscle shortening. Contractures limit a person's range of motion, and are often painful. Regular stretching can prevent contracture. Several drugs are available to reduce cramping, a common complaint in ALS.

An occupational therapist can help design solutions to movement and coordination problems, and provide advice on adaptive devices and home modifications.

Speech and swallowing difficulties can be minimized or delayed through training provided by a speech-language pathologist. This specialist can also provide advice on communication aids, including computer-assisted devices and simpler word boards.

Nutritional advice can be provided by a nutritionist. A person with ALS often needs softer foods to prevent jaw exhaustion or choking. Later in the disease, nutrition may be provided by a gastrostomy tube inserted into the stomach.

Mechanical ventilation may be used when breathing becomes too difficult. Modern mechanical ventilators are small and portable, allowing a person with ALS to maintain the maximum level of function and mobility. Ventilation may be administered through a mouth or nose piece, or through a tracheostomy tube. This tube is inserted through a small hole made in the windpipe. In addition to providing direct access to the airway, the tube also decreases the risk aspiration. While many people with rapidly progressing ALS choose not to use ventilators for lengthy periods, they are increasingly being used to prolong life for a short time.

The progressive nature of ALS means that most persons will eventually require full-time nursing care. This care is often provided by a spouse or other family member. While the skills involved are not difficult to learn, the physical and emotional burden of care can be over-whelming. Caregivers need to recognize and provide for their own needs as well as those of people with ALS, to prevent depression, burnout, and bitterness.

Throughout the disease, a support group can provide important psychological aid to affected persons and their caregivers as they come to terms with the losses ALS inflicts. Support groups are sponsored by both the ALS Society and the Muscular Dystrophy Association.

Alternative treatment

Given the grave prognosis and absence of traditional medical treatments, it is not surprising that a large number of alternative treatments have been tried for ALS. Two studies published in 1988 suggested that amino-acid therapies may provide some improvement for some people with ALS. While individual reports claim benefits for megavitamin therapy, herbal medicine, and removal of dental fillings, for instance, no evidence suggests that these offer any more than a brief psychological boost, often followed by a more severe letdown when it becomes apparent the disease has continued unabated. However, once the causes of ALS are better understood, alternative therapies may be more intensively studied. For example, if damage by free radicals turns out to be the root of most of the symptoms, antioxidant vitamins and supplements may be used more routinely to slow the progression of ALS. Or, if environmental toxins are implicated, alternative therapies with the goal of detoxifying the body may be of some use.

Prognosis

ALS usually progresses rapidly, and leads to death from respiratory infection within three to five years in most cases. The slowest disease progression is seen in those who are young and have their first symptoms in the limbs. About 10% of people with ALS live longer than eight years.

Prevention

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

Resources

BOOKS

Adams, Raymond D., Maurice Victor, and Allan H. Ropper. Adams'& Victor's Principles of Neurology, 6th ed. New York: McGraw Hill, 1997.

Brown, Robert H. "The motor neuron diseases." In Harrison's Principles of Internal Medicine, 14th ed., edited by Anthony S. Fauci, et al., pp. 2368-2372. New York: McGraw-Hill, 1998.

Feldman, Eva L. "Motor neuron diseases." In Cecil Textbook of Medicine, 21st ed., edited by Lee Goldman and J. Claude Bennett, pp. 2089-2092. Philadelphia: W. B. Saunders, 2000.

Kimura, Jun, and Ryuji Kaji. Physiology of ALS and Related Diseases. Amsterdam: Elsevier Science, 1997.

Mitsumoto, Hiroshi, David A. Chad, Erik Pioro, and Sid Gilman. Amyotrophic Lateral Sclerosis. New York: Oxford University Press, 1997.

PERIODICALS

Ansevin, C. F. "Treatment of ALS with pleconaril." Neurology 56, no. 5 (2001): 691-692.

Eisen, A., and M. Weber. "The motor cortex and amyotrophic lateral sclerosis." Muscle and Nerve 24, no. 4 (2001): 564-573.

Gelanis, D. F. "Respiratory Failure or Impairment in Amyotrophic Lateral Sclerosis." Current treatment options in neurology 3, no. 2 (2001): 133-138.

Ludolph, A. C. "Treatment of amyotrophic lateral sclerosis—what is the next step?" Journal of Neurology 246, Suppl 6 (2000): 13-18.

Pasetti, C., and G. Zanini. "The physician-patient relationship in amyotrophic lateral sclerosis." Neurological Science 21, no. 5 (2000): 318-323.

Robberecht, W. "Genetics of amyotrophic lateral sclerosis." Journal of Neurology 246, Suppl 6 (2000): 2-6.

Robbins, R. A., Z. Simmons, B. A. Bremer, S. M. Walsh, and S. Fischer. "Quality of life in ALS is maintained as physical function declines." Neurology 56, no. 4 (2001): 442-444.

ORGANIZATIONS

ALS Association of America. 27001 Agoura Road, Suite 150, Calabasas Hills, CA 91301-5104. (800) 782-4747 (Information and Referral Service) or (818) 880-9007; Fax: (818) 880-9006. http://www.alsa.org/als/

American Academy of Family Physicians. 11400 Tomahawk Creek Parkway, Leawood, KS 66211-2672. (913) 906-6000. fp@aafp.org. http://www.aafp.org/.

American Academy of Neurology. 1080 Montreal Avenue, St. Paul, Minnesota 55116. (651) 695-1940; Fax: (651) 695-2791. info@aan.org. http://www.aan.com/.

American Medical Association, 515 N. State Street, Chicago, IL 60610. (312) 464-5000. http://www.ama-assn.org/.

Centers for Disease Control and Prevention. 1600 Clifton Road, Atlanta, GA 30333. (404) 639-3534 or (800) 311-3435. http://www.cdc.gov/netinfo.htm, http://www.cdc.gov/ncidod/eid/vol7no1/brown.htm.

Muscular Dystrophy Association. 3300 East Sunrise Drive, Tucson, AZ 85718-3208. (520) 529-2000 or (800) 572-1717;520) 529-5300. www.mdausa.org.

WEBSITES

ALS Society of Canada. http://www.als.ca/.

ALS Survival Guide. http://www.lougehrigsdisease.net/.

American Academy of Family Physicians. http://www.aafp.org/afp/990315ap/1489.html.

National Organization for Rare Diseases. http://www.stepstn.com/cgi-win/nord.exe?proc=Redirect&type=rdb_sum&id=57.htm.

National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/health_and_medical/disorders/amyotrophiclateralsclerosis_doc.htm.

National Library of Medicine. http://www.nlm.nih.gov/medlineplus/amyotrophiclateralsclerosis.html.

World Federation of Neurology. http://www.wfnals.org/.


L. Fleming Fallon, Jr., MD, DrPH


Dental Dictionary: amyotrophic lateral sclerosis
Top

n

A degenerative disease of the motor neurons, characterized by atrophy of the muscles of the hands, forearms, and legs, and spreading to involve most of the body. It is commonly known as Lou Gehrig’s disease.

Alternative Medicine Encyclopedia: Lou Gehrig's Disease
Top

Definition

Lou Gehrig's disease, or amyotrophic lateral sclerosis (ALS), is a neurodegenerative disease of unknown cause that breaks down tissues in the nervous system and affects the nerves responsible for movement. Its common name comes from the professional baseball player whose career was ended because of it.

Description

Lou Gehrig's disease is a disease of the motor neurons, those nerve cells reaching from the brain to the spinal cord (upper motor neurons) and the spinal cord to the peripheral nerves (lower motor neurons) that control muscle movement. In Lou Gehrig's disease, for unknown reasons, these neurons die, leading to a progressive loss of the ability to move virtually any of the muscles in the body. The disease affects "voluntary" muscles, those controlled by conscious thought, such as the arm, leg, and trunk muscles. Lou Gehrig's disease, in and of itself, does not affect sensation, thought processes, the heart muscle, or the "smooth" muscle of the digestive system, bladder, and other internal organs. Most sufferers retain function of their eye muscles, as well.

"Amyotrophic" refers to the loss of muscle bulk, a cardinal sign of ALS. "Lateral" indicates one of the regions of the spinal cord affected, and "sclerosis" describes the hardened tissue that develops in place of healthy nerves. Lou Gehrig's disease affects approximately 50,000 people in the United States, with about 5,000 new cases each year. The onset usually begins between the ages of 40 and 70, although younger onset is possible. Men have a slightly higher chance of developing the disease than women.

Causes & Symptoms

Causes

The symptoms of Lou Gehrig's disease are caused by the death of motor neurons in the spinal cord and brain. Normally, these neurons convey electrical messages from the brain to the muscles to stimulate movement in the arms, legs, trunk, neck, and head. As motor neurons die, the muscles cannot be moved as effectively, and weakness results. In addition, lack of stimulation leads to muscle wasting, or loss of bulk. Involvement of the upper motor neurons causes spasms and increased tone in the limbs, and abnormal reflexes. Involvement of the lower motor neurons causes muscle wasting and twitching (fasciculations).

Although many causes of motor neuron degeneration have been suggested for Lou Gehrig's disease, none has yet been proven responsible. Results of recent research have implicated toxic molecular fragments known as free radicals. Some evidence suggests that a cascade of events leads to excess free radical production inside motor neurons, leading to their death. Why free radicals should be produced in excess amounts is unclear, as is whether this excess is the cause or the effect of other degenerative processes. Additional agents within this toxic cascade may include excessive levels of a neurotransmitter known as glutamate, which may overstimulate motor neurons, thereby increasing free-radical production, and a faulty detoxification enzyme known as SOD–1, for superoxide dismutase type 1. The actual pathway of destruction is not known, however, nor is the trigger for the rapid degeneration that marks Lou Gehrig's disease. Further research may show that other pathways are involved, perhaps ones even more important than this one. Autoimmune factors or premature aging may play some role, as could viral agents or environmental toxins.

Two major forms of ALS are known: familial and sporadic. Familial Lou Gehrig's disease accounts for about 10% of all Lou Gehrig's disease cases. As the name suggests, familial Lou Gehrig's disease is believed to be caused by the inheritance of one or more faulty genes. About 15% of families with this type of Lou Gehrig's disease have mutations in the gene for SOD–1. SOD–1 gene defects are dominant, meaning only one gene copy is needed to develop the disease. Therefore, a parent with the faulty gene has a 50% chance of passing the gene along to a child. Sporadic Lou Gehrig's disease has no known cause. While many environmental toxins have been suggested as causes, to date no research has confirmed any of the candidates investigated, including aluminum and metal dental fillings. As research progresses, it is likely that many cases of sporadic Lou Gehrig's disease will be shown to have a genetic basis, as well. A third type, called Western Pacific Lou Gehrig's disease occurs in Guam and other Pacific islands. This form of the disease combines symptoms of both ALS and Parkinson's disease.

Symptoms

The earliest sign of Lou Gehrig's disease is most often weakness in the arms or legs, at first usually more pronounced on one side than the other. Loss of function is usually more rapid in the legs among people with familial Lou Gehrig's disease, and in the arms among those with sporadic Lou Gehrig's disease. Leg weakness may first become apparent by an increased frequency of stumbling on uneven pavement, or an unexplained difficulty climbing stairs. Arm weakness may lead to difficulty grasping and holding a cup, for instance, or loss of dexterity in the fingers.

Less often, the earliest sign of Lou Gehrig's disease is weakness in the bulbar muscles, those muscles in the mouth and throat that control chewing, swallowing, and speaking. A person with bulbar weakness may become hoarse or tired after speaking at length, or speech may become slurred.

In addition to muscle weakness, the other cardinal signs of Lou Gehrig's disease are muscle wasting and persistent twitching, which is known as fasciculation. These are usually noticed after weakness in muscles becomes obvious. Fasciculation is also common in people without the disease, and is virtually never the first sign of Lou Gehrig's disease.

While initial weakness may be limited to one region, Lou Gehrig's disease almost always progresses rapidly to involve virtually all the 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 the head up. Weakness of the respiratory muscles makes breathing and coughing difficult, and poor swallowing control increases the likelihood of inhalation of food or saliva (aspiration). Aspiration increases the likelihood of lung infection, which is often the cause of death. With a ventilator and scrupulous bronchial hygiene, a person with Lou Gehrig's disease may live much longer than the average, although weakness and wasting will continue to erode any remaining functional abilities. Most people with Lou Gehrig's disease continue to retain function of the extraocular muscles that control movement of the eyes, allowing some communication to take place with simple blinks or through use of a computer–assisted device.

Diagnosis

The diagnosis of Lou Gehrig's disease begins with a complete medical history and physical exam, plus a neurological exam to determine the distribution and extent of weakness. An electrical test of muscle function, called an electromyogram, or EMG, is an important part of the diagnostic process. Various other tests, including blood and urine tests, x rays, and CT scans, may be done to rule out other possible causes of the symptoms, such as tumors of the skull base or high cervical spinal cord, thyroid disease, spinal arthritis, lead poisoning, or severe vitamin deficiency. Lou Gehrig's disease is rarely misdiagnosed following a careful review of all these factors.

Treatment

There is no cure for Lou Gehrig's disease, and no treatment that can significantly alter its course. There are many things that can be done, however, to help maintain quality of life and to retain functional ability even in the face of progressive weakness.

Two studies published in 1988 suggested that amino–acid therapies may provide some improvement for some people with Lou Gehrig's disease. While individual patient reports claim benefits for megavitamin therapy, herbal medicine, and removal of dental fillings, for instance, no evidence suggests that these offer any more than a brief psychological boost, often followed by a more severe letdown when it becomes apparent the disease has continued unabated. However, once the causes of Lou Gehrig's disease are better understood, alternative therapies may be researched more intensively. For example, if damage by free radicals turns out to be the root of most of the symptoms, antioxidant vitamins and supplements may be used more routinely to slow the progression of Lou Gehrig's disease. Or, if environmental toxins are implicated, alternative therapies with the goal of detoxifying the body may be of some use. In 2002, the Food and Drug Administration (FDA) granted approval for one company to begin trials on use of creatine, an amino acid dietary supplement, to treat ALS. Preliminary data from trials show that creatine might slow progression of Lou Gehrig's disease, but research remains to be completed before approval of the supplement for treatment of ALS.

A physical therapist works with the patient and family to implement exercise and stretching programs to maintain strength and range of motion, and to promote general health. Swimming may be a good choice for people with Lou Gehrig's disease, as it provides a low–impact workout to most muscle groups. One result of chronic inactivity is contracture, or muscle shortening. Contractures limit a person's range of motion, and are often painful. Regular stretching can prevent contracture.

An occupational therapist can help design solutions for movement and coordination problems, and provide advice on adaptive devices and home modifications. Speech and swallowing difficulties can be minimized or delayed through training provided by a speech-language pathologist. This specialist can also provide advice on communication aids, including computer-assisted devices and simpler word boards. Nutritional advice can be provided by a nutritionist. A person with Lou Gehrig's disease often needs softer foods to prevent jaw exhaustion or choking. Later in the disease, nutrition may be provided by a gastrostomy tube inserted into the stomach.

Allopathic Treatment

As of early 2002, only one drug had been approved for treatment of Lou Gehrig's disease. Riluzole (Rilutek) appears to provide on average a three-month increase in life expectancy when taken regularly early in the disease, and shows a significant slowing of the loss of muscle strength. Riluzole acts by decreasing glutamate release from nerve terminals. Experimental trials of nerve growth factor have not demonstrated any benefit. No other drug or vitamin currently available has been shown to have any effect on the course of Lou Gehrig's disease. However, in 2002, researchers had identified how a common drug prescribed for acne could slow the progression of cell death in the brain that causes ALS. The drug, called minocycline, can safely be taken orally. Scientists are now working on a combination of minocycline with other drugs to better target a more powerful therapy for Lou Gehrig's disease patients.

Mechanical ventilation may be used when breathing becomes too difficult. Modern mechanical ventilators are small and portable, allowing a person with Lou Gehrig's disease to maintain the maximum level of function and mobility. Ventilation may be administered through a mouth or nose piece, or through a tracheostomy tube. This tube is inserted through a small hole made in the windpipe. In addition to providing direct access to the airway, the tube also decreases aspiration. While many people with rapidly progressing Lou Gehrig's disease choose not to use ventilators for lengthy periods, they are increasingly used to prolong life for a short time.

The progressive nature of Lou Gehrig's disease means that most patients will eventually require full-time nursing care. This care is often provided by a spouse or other family member. While the skills involved are not difficult to learn, the physical and emotional burden of care can be overwhelming. Caregivers need to recognize and provide for their own needs, as well as those of the patient, to prevent depression and burnout. Throughout the disease, a support group can provide important psychological aid to the patient, and also act as a caregiver as they come to terms with the losses that Lou Gehrig's disease inflicts. Support groups are sponsored by both the Lou Gehrig's Disease Society and the Muscular Dystrophy Association.

Expected Results

Lou Gehrig's disease usually progresses rapidly, and leads to death from respiratory infection within three to five years in most cases. The slowest disease progression is seen in those who are young and have their first symptoms in the limbs. About 10% of people with Lou Gehrig's disease live longer than eight years.

Prevention

There is no known way to prevent Lou Gehrig's disease or to alter its course.

Resources

Books

Mitsumoto, Hiroshi and Forbes H. Norris Jr., eds. Amyotrophic Lateral Sclerosis: A Comprehensive Guide to Management. Demos Publications, 1996.

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

Periodicals

"Creatine Granted Orphan Drug Designation." Drug Topics (April 15, 2002):HSE6.

The ALS Digest.http://http1.brunel.ac.uk:8080/~hssrsdn/alsig/alsig.htm.

"Research: Common Acne Antibiotic Minocycline Delays Progression of ALS." Immunotherapy Weekly (June 5, 2002):7.

The ALS Newsletter. Available from the Muscular Dystrophy Association.

Organizations

The ALS Association. 21021 Ventura Blvd., Suite #321, Woodland Hills, CA 91364. (818) 340–7500.

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

Other

With Strength and Courage: Understanding and Living with ALS. Videotape available from the Muscular Dystrophy Association.

[Article by: Kathleen Wright; Teresa G. Odle]

 
Columbia Encyclopedia: amyotrophic lateral sclerosis
Top
amyotrophic lateral sclerosis (ALS) (ā'mīətrōf'ik, sklĭrō'sĭs) or motor neuron disease, sometimes called Lou Gehrig's disease, degenerative disease that affects motor neurons in the brain and spinal cord, preventing them from sending impulses to the muscles. The muscles atrophy quickly, causing weakness, paralysis, and eventual death, usually when the muscles that control respiration fail. The intellect, eye motion, and bladder control are not affected. ALS sometimes originates in the brain, causing initial symptoms such as difficulty in swallowing or talking; in other cases it originates in the spinal cord, causing initial symptoms such as weakness in the extremities. About 10% of ALS cases are hereditary. ALS usually develops after age 40; more men are affected than women.

There appear to be several causes of ALS. In 1991 a research team led by Teepu Siddique and Robert H. Brown, Jr. located the gene for familial ALS on chromosome 21. A later discovery pinpointed a mutation in the gene that codes for an enzyme, superoxide dismutase (SOD), as responsible for a percentage of familial cases. These defects do not appear to be present in the more common nonfamilial, or "sporadic," form of the disease. In addition to genetic factors, scientists have studied the buildup of the chemical glutamate that occurs in ALS patients. Glutamate normally acts as a neurotransmitter in the brain, with excess amounts being absorbed by the cells. In ALS patients the reabsorption process fails, and the buildup of glutamate selectively destroys motor neurons. Other possible causes of ALS include defects in the gene that makes the neurofilament proteins that support nerve cell axons, and antibodies that interfere with calcium channels in the cells and cause a toxic buildup of calcium in the neurons.

There is no cure for ALS. Devices such as wheelchairs and speech synthesizers can help patients maintain independence. Research into treatment has concentrated on neurotrophic factors (proteins that assist nerve growth and health) and glutamate blockers. Rilutek (formerly Riluzole), the first drug approved by the Food and Drug Administration for treatment of ALS (1995), adds a few months to the life expectancy of most patients but does not relieve symptoms. Another drug, myotrophin, seemed somewhat promising in early studies (1996), but its effectiveness was not confirmed and it has not been approved. Baseball star Lou Gehrig died of ALS in 1941, bringing it national attention.


Science Q&A: What is Lou Gehrig's disease?
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Sometimes called Lou Gehrig's disease, amyotrophic lateral sclerosis (ALS) is a motor neuron disease of middle or late life. It results from a progressive degeneration of nerve cells controlling voluntary motor functions that ends in death three to 10 years after onset. There is no cure for it. At the beginning of the disease, the patient notices weakness in the hands and arms, with involuntary muscle quivering and possible muscle cramping or stiffness. Eventually all four extremities become involved. As nerve degeneration progresses, disability occurs and physical independence declines until the patient, while mentally and intellectually aware, can no longer swallow or move.

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Veterinary Dictionary: amyotrophic lateral sclerosis
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A type of motor disorder of the nervous system in humans in which there is destruction of the anterior horn cells and pyramidal tract. The cause is unknown. It is characterized by weakness, spasticity and muscle atrophy and is fatal in most cases. One form of hereditary canine spinal muscular atrophy is similar to this disease.

Wikipedia: Amyotrophic lateral sclerosis
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Amyotrophic Lateral Sclerosis (Lou Gehrig's Disease)
Classification and external resources
ICD-10 G12.2
ICD-9 335.20
OMIM 105400
DiseasesDB 29148
MedlinePlus 000688
eMedicine neuro/14 emerg/24 pmr/10
MeSH D000690

Amyotrophic lateral sclerosis is a form of motor neuron disease. ALS, sometimes called Maladie de Charcot, is a progressive,[1] fatal, neurodegenerative disease caused by the degeneration of motor neurons, the nerve cells in the central nervous system that control voluntary muscle movement. The condition is often called Lou Gehrig's Disease in North America, after the New York Yankees baseball icon who was diagnosed with the disease in 1939 and died from it in 1941, at age thirty-seven. Today, renowned physicist Stephen Hawking and guitar virtuoso Jason Becker are likely the best-known living ALS patients. The disorder causes muscle weakness and atrophy throughout the body as both the upper and lower motor neurons degenerate, ceasing to send messages to muscles. Unable to function, the muscles gradually weaken, develop fasciculations (twitches) because of denervation, and eventually atrophy because of that denervation. The patient may ultimately lose the ability to initiate and control all voluntary movement; bladder and bowel sphincters and the muscles responsible for eye movement are usually (but not always) spared.

Cognitive function is generally spared except in certain situations such as when ALS is associated with frontotemporal dementia.[2] However, there are reports of more subtle cognitive changes of the frontotemporal type in many patients when detailed neuropsychological testing is employed. Sensory nerves and the autonomic nervous system, which controls functions like sweating, generally remain functional.

Contents

Symptoms

Initial symptoms

The onset of ALS may be so subtle that the symptoms are frequently overlooked. The earliest symptoms are obvious weakness and/or muscle atrophy. This is followed by twitching, cramping, or stiffness of affected muscles; muscle weakness affecting an arm or a leg; and/or slurred and nasal speech. The twitching, cramping, etc. associated with ALS is a result of the dying motor neurons, therefore these symptoms without clinical weakness or atrophy of affected muscle is likely not ALS.

The parts of the body affected by early symptoms of ALS depend on which motor neurons in the body are damaged first. About 75% of people experience "limb onset" ALS. In some of these cases, symptoms initially affect one of the legs, and patients experience awkwardness when walking or running or they notice that they are tripping or stumbling more often. Other limb onset patients first see the effects of the disease on a hand or arm as they experience difficulty with simple tasks requiring manual dexterity such as buttoning a shirt, writing, or turning a key in a lock. Occasionally the symptoms remain confined to one limb; this is known as monomelic amyotrophy.

About 25% of cases are "bulbar onset" ALS. These patients first notice difficulty speaking clearly. Speech becomes garbled and slurred. Nasality and loss of volume are frequently the first symptoms. Difficulty swallowing, and loss of tongue mobility follow. Eventually total loss of speech and the inability to protect the airway when swallowing are experienced.

Regardless of the part of the body first affected by the disease, muscle weakness and atrophy spread to other parts of the body as the disease progresses. Patients experience increasing difficulty moving, swallowing (dysphagia), and speaking or forming words (dysarthria). Symptoms of upper motor neuron involvement include tight and stiff muscles (spasticity) and exaggerated reflexes (hyperreflexia) including an overactive gag reflex. An abnormal reflex commonly called Babinski's sign (the big toe extends upward and other toes spread out) also indicates upper motor neuron damage. Symptoms of lower motor neuron degeneration include muscle weakness and atrophy, muscle cramps, and fleeting twitches of muscles that can be seen under the skin (fasciculations). Around 15–45% of patients experience pseudobulbar affect, also known as "emotional lability", which consists of uncontrollable laughter, crying or smiling, attributable to degeneration of bulbar upper motor neurons resulting in exaggeration of motor expressions of emotion.

To be diagnosed with ALS, patients must have signs and symptoms of both upper and lower motor neuron damage that cannot be attributed to other causes.

Emerging symptoms

Although the sequence of emerging symptoms and the rate of disease progression vary from person to person, eventually patients will not be able to stand or walk, get in or out of bed on their own, or use their hands and arms. Difficulty swallowing and chewing impair the patient's ability to eat normally and increase the risk of choking. Maintaining weight will then become a problem. Because the disease usually does not affect cognitive abilities, patients are aware of their progressive loss of function and may become anxious and depressed. A small percentage of patients go on to develop frontotemporal dementia characterized by profound personality changes; this is more common among those with a family history of dementia. A larger proportion of patients experience mild problems with word-generation, attention, or decision-making. Cognitive function may be affected as part of the disease process or could be related to poor breathing at night (nocturnal hypoventilation). Health care professionals need to explain the course of the disease and describe available treatment options so that patients can make informed decisions in advance.

As the diaphragm and intercostal muscles (rib cage) weaken, forced vital capacity and inspiratory pressure diminish. In bulbar onset ALS, this may occur before significant limb weakness is apparent. Bilevel positive pressure ventilation (frequently referred to by the tradename BiPAP) is frequently used to support breathing, first at night, and later during the daytime as well. It is recommended that long before BiPAP becomes insufficient, patients must decide whether to have a tracheostomy and long term mechanical ventilation. At this point, some patients choose palliative hospice care. Most people with ALS die of respiratory failure or pneumonia. Death usually occurs within two to five years of diagnosis. Although the disease can strike at any age, most people are between forty and seventy years of age when the disease strikes and men are affected slightly more frequently than women. Roughly fifteen people are newly diagnosed with ALS each day. An estimated 5,000 people in the United States are diagnosed with the disease each year. ALS, a progressive disease, leads to death in half of the people diagnosed within three years and ninety percent within six years.

ALS predominantly affects the motor neurons, and in the majority of cases the disease does not impair a patient's mind, personality, intelligence, or memory. Nor does it affect a person's ability to see, smell, taste, hear, or feel touch. Control of eye muscles is the most preserved function, although some patients with an extremely long duration of disease (20+ years) may lose eye control too. Unlike multiple sclerosis, bladder and bowel control are usually preserved in ALS, although as a result of immobility and diet changes, intestinal problems such as constipation can require intensive management.

Cause and risk factors

Scientists have not found a definitive cause for ALS and the onset of the disease has been linked to several factors, including: a virus; exposure to neurotoxins or heavy metals; DNA defects; immune system abnormalities; occupational factors such as military service and elite sports; and enzyme abnormalities. Surgeries involving the spinal cord have also been thought to play a role in the onset of ALS due to the disruption of nerve fibers. There is a known hereditary factor in familial ALS (FALS); however, there is no known hereditary component in the 90–95% cases diagnosed as sporadic ALS. An inherited genetic defect on chromosome 21 is associated with approximately 20% of familial cases of ALS.[3][4] This mutation is believed to be autosomal dominant. The children of those diagnosed with familial ALS have a higher risk factor for developing the disease; however, those who have close family members diagnosed with sporadic ALS have no greater a risk factor than the general population.[5]

Some causative factors have been suggested for the increased incidence in the western Pacific. Prolonged exposure to a dietary neurotoxin called BMAA is one suspected risk factor in Guam; the neurotoxin is a compound found in the seed of the cycad Cycas circinalis,[6] a tropical plant found in Guam, which was used in the human food supply during the 1950s and early 1960s.

The very high incidence of the disease among Italian soccer players (more than five times higher than normally expected) has raised the concern of a possible link between the disease and the use of pesticides on the soccer fields.[7][8]

According to the ALS Association, military veterans are at an increased risk of contracting ALS. In its report ALS in the Military,[9] the group pointed to an almost 60% greater chance of the disease in military veterans than the general population. For Gulf War veterans, the chance is seen as twice that of veterans not deployed to the Persian Gulf in a joint study by the Veterans Affairs Administration and the DOD.[10][11]

Dietary intake of polyunsaturated fatty acids (PUFA) has been shown in several studies to decrease the risk of developing ALS [12][13]

Pathophysiology

SOD1

The cause of ALS is not known, though an important step toward answering that question came in 1993 when scientists discovered that mutations in the gene that produces the Cu/Zn superoxide dismutase (SOD1) enzyme were associated with some cases (approximately 20%) of familial ALS. This enzyme is a powerful antioxidant that protects the body from damage caused by superoxide, a toxic free radical. Free radicals are highly reactive molecules produced by cells during normal metabolism. Free radicals can accumulate and cause damage to DNA and proteins within cells. Although it is not yet clear how the SOD1 gene mutation leads to motor neuron degeneration, researchers have theorized that an accumulation of free radicals may result from the faulty functioning of this gene. Current research, however, indicates that motor neuron death is not likely a result of lost or compromised dismutase activity, suggesting mutant SOD1 induces toxicity in some other way (a gain of function).[14][15]

Studies involving transgenic mice have yielded several theories about the role of SOD1 in mutant SOD1 familial amyotrophic lateral sclerosis. Mice lacking the SOD1 gene entirely do not customarily develop ALS, although they do exhibit an acceleration of age-related muscle atrophy (sarcopenia) and a shortened lifespan (see article on superoxide dismutase). This indicates that the toxic properties of the mutant SOD1 are a result of a gain in function rather than a loss of normal function. In addition, aggregation of proteins has been found to be a common pathological feature of both familial and sporadic ALS (see article on proteopathy). Interestingly, in mutant SOD1 mice, aggregates (misfolded protein accumulations) of mutant SOD1 were found only in diseased tissues, and greater amounts were detected during motor neuron degeneration.[16] It is speculated that aggregate accumulation of mutant SOD1 plays a role in disrupting cellular functions by damaging mitochondria, proteasomes, protein folding chaperones, or other proteins.[17] Any such disruption, if proven, would lend significant credibility to the theory that aggregates are involved in mutant SOD1 toxicity. Critics have noted that in humans, SOD1 mutations cause only 2% or so of overall cases and the etiological mechanisms may be distinct from those responsible for the sporadic form of the disease. To date, the ALS-SOD1 mice remain the best model of the disease for preclinical studies but it is hoped that more useful models will be developed.

Other factors

Studies also have focused on the role of glutamate in motor neuron degeneration. Glutamate is one of the chemical messengers or neurotransmitters in the brain. Scientists have found that, compared to healthy people, ALS patients have higher levels of glutamate in the serum and spinal fluid.[4] Laboratory studies have demonstrated that neurons begin to die off when they are exposed over long periods to excessive amounts of glutamate (excitotoxicity). Now, scientists are trying to understand what mechanisms lead to a buildup of unneeded glutamate in the spinal fluid and how this imbalance could contribute to the development of ALS. Failure of astrocytes to sequester glutamate from the extracellular fluid surrounding the neurones has been proposed as a possible cause of this glutamate-mediated neurodegeneration.

Riluzole is currently the only FDA approved drug for ALS and targets glutamate transporters. Its very modest benefit to patients has bolstered the argument that glutamate is not a primary cause of the disease. The antibiotic ceftriaxone has demonstrated an unexpected effect on glutamate and appears to be a beneficial treatment for ALS in animal models. Ceftriaxone is currently being tested in clinical trials.

Autoimmune responses which occur when the body's immune system attacks normal cells have been suggested as one possible cause for motor neuron degeneration in ALS. Some scientists theorize that antibodies may directly or indirectly impair the function of motor neurons, interfering with the transmission of signals between the brain and muscles. More recent evidence indicates that the nervous system's immune cells, microglia, are heavily involved in the later stages of the disease.

In searching for the cause of ALS, researchers have also studied environmental factors such as exposure to toxic or infectious agents. Other research has examined the possible role of dietary deficiency or trauma. However, as of yet, there is insufficient evidence to implicate these factors as causes of ALS.

Future research may show that many factors, including a genetic predisposition, are involved in the development of ALS.

Diagnosis

No test can provide a definite diagnosis of ALS, although the presence of upper and lower motor neuron signs in a single limb is strongly suggestive. Instead, the diagnosis of ALS is primarily based on the symptoms and signs the physician observes in the patient and a series of tests to rule out other diseases. Physicians obtain the patient's full medical history and usually conduct a neurologic examination at regular intervals to assess whether symptoms such as muscle weakness, atrophy of muscles, hyperreflexia, and spasticity are getting progressively worse.

Because symptoms of ALS can be similar to those of a wide variety of other, more treatable diseases or disorders, appropriate tests must be conducted to exclude the possibility of other conditions. One of these tests is electromyography (EMG), a special recording technique that detects electrical activity in muscles. Certain EMG findings can support the diagnosis of ALS. Another common test measures nerve conduction velocity (NCV). Specific abnormalities in the NCV results may suggest, for example, that the patient has a form of peripheral neuropathy (damage to peripheral nerves) or myopathy (muscle disease) rather than ALS. The physician may order magnetic resonance imaging (MRI), a noninvasive procedure that uses a magnetic field and radio waves to take detailed images of the brain and spinal cord. Although these MRI scans are often normal in patients with ALS, they can reveal evidence of other problems that may be causing the symptoms, such as a spinal cord tumor, multiple sclerosis, a herniated disk in the neck, syringomyelia, or cervical spondylosis.

Based on the patient's symptoms and findings from the examination and from these tests, the physician may order tests on blood and urine samples to eliminate the possibility of other diseases as well as routine laboratory tests. In some cases, for example, if a physician suspects that the patient may have a myopathy rather than ALS, a muscle biopsy may be performed.

Infectious diseases such as human immunodeficiency virus (HIV), human T-cell leukaemia virus (HTLV), Lyme disease,[18] syphilis[19] and tick-borne encephalitis[20] viruses can in some cases cause ALS-like symptoms. Neurological disorders such as multiple sclerosis, post-polio syndrome, multifocal motor neuropathy, CIDP, and spinal muscular atrophy can also mimic certain facets of the disease and should be considered by physicians attempting to make a diagnosis.

Because of the prognosis carried by this diagnosis and the variety of diseases or disorders that can resemble ALS in the early stages of the disease, patients should always obtain a second neurological opinion.

A recent study identified three proteins that are found in significantly lower concentrations in the cerebral spinal fluid of patients with ALS than in healthy individuals [21] . Evaluating the levels of these three proteins proved 95% accurate for diagnosing ALS. Two of the three protein were identified as cystatin C (13.4 kD) and a 4.8 kD peptide fragment of VEGF (Vascular Endothelial Growth Factor). A third 6.7 kD cationic peptide has not yet been identified. These diagnostic biomarkers may be useful in making earlier diagnoses of ALS than previously possible.

Treatment

Medication

Approved drugs

The Food and Drug Administration (FDA) has approved the first drug treatment for the disease: Riluzole (Rilutek). Riluzole is believed to reduce damage to motor neurons by decreasing the release of glutamate via activation of glutamate transporters. In addition, the drug offers a wide array of other neuroprotective effects, by means of sodium and calcium channel blockades,[22] inhibition of protein kinase C,[23] and the promotion of NMDA (N-methyl d-aspartate) receptor antagonism.[22][24] Clinical trials with ALS patients showed that Riluzole lengthens survival by several months, and may have a greater survival benefit for those with a bulbar onset. The drug also extends the time before a patient needs ventilation support. Riluzole does not reverse the damage already done to motor neurons, and patients taking the drug must be monitored for liver damage and other possible side effects. However, this first disease-specific therapy offers hope that the progression of ALS may one day be slowed by new medications or combinations of drugs. A small, open-label study recently suggested that the drug lithium which traditionally is used for the treatment of bipolar affective disorder may slow progression in both animal models and the human form of the disease.[25] However, further research is needed to establish whether the effect is real or not.

Experimental drugs

A number of clinical trials are underway globally for ALS.

KNS-760704 is under clinical investigation in ALS patients. It is hoped that the drug will have a neuroprotective effect. It is the enantiomer of pramipexole, which is approved for the treatment of Parkinson's disease and restless legs syndrome.[26] However, KNS-760704, which has been manufactured to a high degree of enantiomeric purity and which is essentially inactive at dopamine receptors, is not dose limited by the potent dopaminergic properties of pramipexole.[27] The potential utility of KNS-760704 in ALS is being advanced in clinical studies by Knopp Neurosciences Inc. of Pittsburgh, PA.

The tetracycline antibiotic minocycline is also under investigation for the treatment of ALS among other neurological disorders. In rodents with the SOD1 gene mutation that has been associated with ALS, Minocycline was as effective as Riluzole in extending survival, and it delayed the onset of movement problems.[28] It is thought to exert its neuroprotective effects not by affecting glutamate release as with Riluzole, but by inhibiting the release of a mitochondrial protein called cytochrome c into the body of the cell.

The new discovery of RNAi has some promise in treating ALS. In recent studies, RNAi has been used in lab rats to shut off specific genes that lead to ALS. Cytrx Corporation has sponsored ALS research using RNAi gene silencing technology targeted at the mutant SOD1 gene.[29] The mutant SOD1 gene is responsible for causing ALS in a subset of the 10% of all ALS patients who suffer from the familial, or genetic, form of the disease. Cytrx's orally-administered drug Arimoclomol is currently in clinical evaluation as a therapeutic treatment for ALS.

Insulin-like growth factor 1 has also been studied as treatment for ALS. Cephalon and Chiron conducted two pivotal clinical studies of IGF-1 for ALS, and although one study demonstrated efficacy, the second was equivocal, and the product has never been approved by the FDA. In January 2007, the Italian Ministry of Health has requested INSMED corporation's drug, IPLEX, which is a recombinant IGF-1 with Binding Protein 3(IGF1BP3) to be used in a clinical trial for ALS patients in Italy.

Methylcobalamin is being studied in Japan;[30] preliminary results show it significantly lengthens survival time of ALS patients.

Other

Other treatments for ALS are designed to relieve symptoms and improve the quality of life for patients. This supportive care is best provided by multidisciplinary teams of health care professionals such as physicians; pharmacists; physical, occupational, and speech therapists; acupuncturists; nutritionists; social workers; and home care and hospice nurses. Working with patients and caregivers, these teams can design an individualized plan of medical and physical therapy and provide special equipment aimed at keeping patients as mobile and comfortable as possible.

Physicians can prescribe medications to help reduce fatigue, ease muscle cramps, control spasticity, and reduce excess saliva and phlegm. Drugs also are available to help patients with pain, depression, sleep disturbances, and constipation. Pharmacists can advise on best use of medications. This is particularly helpful with regards to patients with dysphagia, which many ALS patients experience. They would also monitor a patient's medications to reduce risk of drug interactions.

Physical therapy and special equipment such as assistive technology can enhance patients' independence and safety throughout the course of ALS. Gentle, low-impact aerobic exercise such as walking, swimming, and stationary bicycling can strengthen unaffected muscles, improve cardiovascular health, and help patients fight fatigue and depression. Range of motion and stretching exercises can help prevent painful spasticity and shortening (contracture) of muscles. Physical therapists can recommend exercises that provide these benefits without overworking muscles. Physiotherapists can suggest devices such as ramps, braces, walkers, and wheelchairs that help patients remain mobile. Occupational therapists can provide or recomment equipment and adaptations to enable people to retain as much independence in activities of daily living as possible.

ALS patients who have difficulty speaking may benefit from working with a speech-language pathologist. These health professionals can teach patients adaptive strategies such as techniques to help them speak louder and more clearly. As ALS progresses, speech-language pathologists can recommend the use of augmentative and alternative communication such as voice amplifiers, speech-generating devices (or voice output communication devices) and/or low tech communication techniques such as alphabet boards or yes/no signals. These methods and devices help patients communicate when they can no longer speak or produce vocal sounds. With the help of occupational Therapists, speech-generating devices can be activated by switches or mouse emulation techniques controlled by small physical movements of, for example, the head, finger or eyes.

Patients and caregivers can learn from speech-language pathologists and nutritionists how to plan and prepare numerous small meals throughout the day that provide enough calories, fiber, and fluid and how to avoid foods that are difficult to swallow. Patients may begin using suction devices to remove excess fluids or saliva and prevent choking. When patients can no longer get enough nourishment from eating, doctors may advise inserting a feeding tube into the stomach. The use of a feeding tube also reduces the risk of choking and pneumonia that can result from inhaling liquids into the lungs. The tube is not painful and does not prevent patients from eating food orally if they wish.

When the muscles that assist in breathing weaken, use of nocturnal ventilatory assistance (intermittent positive pressure ventilation (IPPV) or bilevel positive airway pressure (BIPAP)) may be used to aid breathing during sleep. Such devices artificially inflate the patient's lungs from various external sources that are applied directly to the face or body. When muscles are no longer able to maintain oxygen and carbon dioxide levels, these devices may be used full-time.

Patients may eventually consider forms of mechanical ventilation (respirators) in which a machine inflates and deflates the lungs. To be effective, this may require a tube that passes from the nose or mouth to the windpipe (trachea) and for long-term use, an operation such as a tracheostomy, in which a plastic breathing tube is inserted directly in the patient's windpipe through an opening in the neck. Patients and their families should consider several factors when deciding whether and when to use one of these options. Ventilation devices differ in their effect on the patient's quality of life and in cost. Although ventilation support can ease problems with breathing and prolong survival, it does not affect the progression of ALS. Patients need to be fully informed about these considerations and the long-term effects of life without movement before they make decisions about ventilation support. It must be pointed out that some patients under long-term tracheostomy intermittent positive pressure ventilation with deflated cuffs or cuffless tracheostomy tubes (leak ventilation) are able to speak. This technique preserves speech in some patients with long-term mechanical ventilation.

Social workers and home care and hospice nurses help patients, families, and caregivers with the medical, emotional, and financial challenges of coping with ALS, particularly during the final stages of the disease. Social workers provide support such as assistance in obtaining financial aid, arranging durable power of attorney, preparing a living will, and finding support groups for patients and caregivers. Home nurses are available not only to provide medical care but also to teach caregivers about tasks such as maintaining respirators, giving feedings, and moving patients to avoid painful skin problems and contractures. Home hospice nurses work in consultation with physicians to ensure proper medication, pain control, and other care affecting the quality of life of patients who wish to remain at home. The home hospice team can also counsel patients and caregivers about end-of-life issues.

Both animal and human research suggest calorie restriction (CR) may be contraindicated for those with ALS. Research on a transgenic mouse model of ALS demonstrates that CR may hasten the onset of death in ALS.[31] In that study, Hamadeh et al. also note two human studies[32][33] that they indicate show "low energy intake correlates with death in people with ALS." However, in the first study, Slowie, Paige, and Antel state: "The reduction in energy intake by ALS patients did not correlate with the proximity of death but rather was a consistent aspect of the illness." They go on to conclude: "We conclude that ALS patients have a chronically deficient intake of energy and recommended augmentation of energy intake."[32]

Previously, Pedersen and Mattson also found that in the ALS mouse model, CR "accelerates the clinical course" of the disease and had no benefits.[34] Suggesting that a calorically dense diet may slow ALS, a ketogenic diet in the ALS mouse model has been shown to slow the progress of disease.[35]

Prognosis

Regardless of the part of the body first affected by the disease, it is usual for muscle weakness and atrophy to spread to other parts of the body as the disease progresses. It is important to remember that some patients with ALS have an arrested course with no progression beyond a certain point despite extensive follow-up. Such a pattern is particularly true for young males with predominant upper limb weakness especially on one side (so-called monomelic or Hirayama type motor neuron disease). Eventually people with ALS will not be able to stand or walk, get in or out of bed on their own, or use their hands and arms. In later stages of the disease, individuals have difficulty breathing as the muscles of the respiratory system weaken. Although ventilation support can ease problems with breathing and prolong survival, it does not affect the progression of ALS. Most people with ALS die from respiratory failure, usually within 3 to 5 years from the onset of symptoms. However, about 10-20 percent[36] of those individuals with ALS survive for 10 or more years.

Epidemiology

ALS is one of the most common neuromuscular diseases worldwide, and people of all races and ethnic backgrounds are affected. One to 2 people per 100,000 develop ALS each year.[37] ALS most commonly strikes people between 40 and 60 years of age, but younger and older people can also develop the disease. Men are affected slightly more often than women.

"Familial ALS" accounts for approximately 5%–10% of all ALS cases and is caused by genetic factors. Of these, approximately 1 in 10 are linked to a mutation in copper/zinc superoxide dismutase (SOD1), an enzyme responsible for scavenging free radicals. A recent study has identified a gene called FUS ("Fused in Sarcoma", ALS6) as being responsible for 1 in 20 cases of fALS.[38][39]

Although the incidence of ALS is thought to be regionally uniform, there are three regions in the West Pacific where there has in the past been an elevated occurrence of ALS. This seems to be declining in recent decades. The largest is the area of Guam inhabited by the Chamorro people, who have historically had a high incidence (as much as 143 cases per 100,000 people per year) of a condition called Lytico-Bodig disease which is a combination of ALS, Parkinsonism, and dementia.[40] Two more areas of increased incidence are the Kii peninsula of Japan and West Papua.[41][42]

Although there have been reports of several "clusters" including three American football players from the San Francisco 49ers, more than fifty soccer players in Italy [7], three soccer-playing friends in the south of England,[43] and reports of conjugal (husband and wife) cases in the south of France,[44][45][46][47][48] these are statistically plausible chance events. Although many authors consider ALS to be caused by a combination of genetic and environmental risk factors, so far the latter have not been firmly identified, other than a higher risk with increasing age.

Etymology

Amyotrophic comes from the Greek language: A- means "no", myo refers to "muscle", and trophic means "nourishment"; amyotrophic therefore means "no muscle nourishment," which describes the characteristic atrophication of the sufferer's disused muscle tissue. Lateral identifies the areas in a person's spinal cord where portions of the nerve cells that are affected are located. As this area degenerates it leads to scarring or hardening ("sclerosis") in the region.

History

Timeline
Year Event
1850 English scientist Augustus Waller describes the appearance of shriveled nerve fibers
1869 French doctor Jean-Martin Charcot first describes ALS in scientific literature
1881 "On Amyotrophic Lateral Sclerosis" is translated into English and published in a three-volume edition of Lectures on the Diseases of the Nervous System
1939 ALS becomes a cause célèbre in the United States when baseball legend Lou Gehrig's career—and, two years later, his life—are ended by the disease. He gives his farewell speech on July 4.
1950s ALS epidemic occurs among the Chamorro people on Guam
1991 Researchers link chromosome 21 to FALS (Familial ALS)
1993 SOD1 gene on chromosome 21 found to play a role in some cases of FALS
1996 Rilutek becomes the first FDA-approved drug for ALS
1998 The El Escorial criteria is developed as the standard for classifying ALS patient in clinical research
2001 Alsin gene on chromosome 2 found to cause ALS2

Notable people affected by ALS

Notable people living with ALS include:

Notable people who have died of ALS include:

See also

References

  1. ^ amyotrophic lateral sclerosis at Dorland's Medical Dictionary
  2. ^ Phukan J, Pender NP, Hardiman O (2007). "Cognitive impairment in amyotrophic lateral sclerosis". Lancet Neurol 6 (11): 994–1003. doi:10.1016/S1474-4422(07)70265-X. PMID 17945153. http://linkinghub.elsevier.com/retrieve/pii/S1474-4422(07)70265-X. 
  3. ^ Conwit, Robin A. (December 2006). "Preventing familial ALS: A clinical trial may be feasible but is an efficacy trial warranted?". Journal of the Neurological Sciences 251 (1–2): 1–2. doi:10.1016/j.jns.2006.07.009. ISSN 0022-510X. 
  4. ^ a b Al-Chalabi, Ammar; P. Nigel Leigh (August 2000). "Recent advances in amyotrophic lateral sclerosis". Current Opinion in Neurology 13 (4): 397–405. ISSN 1473-6551. PMID 10970056. 
  5. ^ http://web.archive.org/web/20041115214832/http://www.alsphiladelphia.org/pennstatehershey/newsletters/newsletter_spring04.htm
  6. ^ Khabazian I, Bains JS, Williams DE, Cheung J, Wilson JM, Pasqualotto BA, Pelech SL, Andersen RJ, Wang YT, Liu L, Nagai A, Kim SU, Craig UK, Shaw CA (August 2002). "Isolation of various forms of sterol beta-D-glucoside from the seed of Cycas circinalis: neurotoxicity and implications for ALS-parkinsonism dementia complex". J. Neurochem. 82 (3): 516–28. PMID 12153476. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0022-3042&date=2002&volume=82&issue=3&spage=516. Retrieved 2009-03-13. 
  7. ^ a b "Sla, indagini nei club. Pesticidi nel mirino". http://www.corriere.it/sport/08_ottobre_03/sla_indagine_pesticidi_fd04f986-911c-11dd-9f28-00144f02aabc.shtml. Retrieved 2008-10-02. 
  8. ^ "Sla, una strage nel calcio". http://www.gazzetta.it/Calcio/Altro_Calcio/Primo_Piano/2007/11_Novembre/30/sla_3011.shtml. Retrieved 2008-10-02. 
  9. ^ "ALS in the Military". The ALS Association. 2007-05-17. http://www.alsa.org/files/pdf/als_military_paper.pdf. Retrieved 2008-05-01. 
  10. ^ "Occurrence of ALS higher in Gulf War veterans". http://www.bcm.edu/fromthelab/vol02/is10/03oct_n1.htm. 
  11. ^ "Veterans get ALS disability". http://www.baltimoresun.com/news/nation/bal-te.als25jul25,0,7448073.story. 
  12. ^ Veldink JH, Kalmijn S, Groeneveld GJ, Wunderink W, Koster A, de Vries JH, van der Luyt J, Wokke JH, Van den Berg LH (April 2007). "Intake of polyunsaturated fatty acids and vitamin E reduces the risk of developing amyotrophic lateral sclerosis". J. Neurol. Neurosurg. Psychiatr. 78 (4): 367–71. doi:10.1136/jnnp.2005.083378. PMID 16648143. http://jnnp.bmj.com/cgi/pmidlookup?view=long&pmid=16648143. Retrieved 2009-03-13. 
  13. ^ Okamoto K, Kihira T, Kondo T, Kobashi G, Washio M, Sasaki S, Yokoyama T, Miyake Y, Sakamoto N, Inaba Y, Nagai M (October 2007). "Nutritional status and risk of amyotrophic lateral sclerosis in Japan". Amyotroph Lateral Scler 8 (5): 300–4. doi:10.1080/17482960701472249. PMID 17852010. http://www.informaworld.com/openurl?genre=article&doi=10.1080/17482960701472249&magic=pubmed||1B69BA326FFE69C3F0A8F227DF8201D0. Retrieved 2009-03-13. 
  14. ^ Reaume A, Elliott J, Hoffman E, Kowall N, Ferrante R, Siwek D, Wilcox H, Flood D, Beal M, Brown R, Scott R, Snider W (1996). "Motor neurons in Cu/Zn superoxide dismutase-deficient mice develop normally but exhibit enhanced cell death after axonal injury". Nat Genet 13 (1): 43–7. doi:10.1038/ng0596-43. PMID 8673102. 
  15. ^ Bruijn L, Houseweart M, Kato S, Anderson K, Anderson S, Ohama E, Reaume A, Scott R, Cleveland D (1998). "Aggregation and motor neuron toxicity of an ALS-linked SOD1 mutant independent from wild-type SOD1". Science 281 (5384): 1851–4. doi:10.1126/science.281.5384.1851. PMID 9743498. 
  16. ^ Furukawa Y, Fu R, Deng H, Siddique T, O'Halloran T (2006). "Disulfide cross-linked protein represents a significant fraction of ALS-associated Cu, Zn-superoxide dismutase aggregates in spinal cords of model mice". Proc Natl Acad Sci U S A 103 (18): 7148–53. doi:10.1073/pnas.0602048103. PMID 16636274. 
  17. ^ Boillée S, Vande Velde C, Cleveland D (2006). "ALS: a disease of motor neurons and their nonneuronal neighbors". Neuron 52 (1): 39–59. doi:10.1016/j.neuron.2006.09.018. PMID 17015226. 
  18. ^ Hansel Y, Ackerl M, Stanek G. (1995). "ALS-like sequelae in chronic neuroborreliosis". Wien Med Wochenschr. 145 (7-8): 186–8. PMID 7610670. 
  19. ^ el Alaoui-Faris M, Medejel A, al Zemmouri K, Yahyaoui M, Chkili T (1990). "Amyotrophic lateral sclerosis syndrome of syphilitic origin. 5 cases". Rev Neurol (Paris) 146 (1): 41–4. PMID 2408129. 
  20. ^ Umanekii KG, Dekonenko EP (1983). "Structure of progressive forms of tick-borne encephalitis". Zh Nevropatol Psikhiatr Im S S Korsakova. 83 (8): 1173–9. PMID 6414202. 
  21. ^ Pasinetti G, Ungar L, Lange D, Yemul S, Deng H, Yuan X, Brown R, Cudkowicz M, Newhall K, Peskind E, Marcus S, Ho L (2006). "Identification of potential CSF biomarkers in ALS". Neurology 66 (8): 1218–22. doi:10.1212/01.wnl.0000203129.82104.07. PMID 16481598. 
  22. ^ a b Hubert JP, Delumeau JC, Glowinski J, Prémont J, Doble A. (1994). "Antagonism by riluzole of entry of calcium evoked by NMDA and veratridine in rate cultured granule cells: evidence for a dual mechanism of action". Br. J. Pharmacol. 113 (1): 261–267. PMID 7812619. 
  23. ^ Noh KM, Hwang JY, Shin HC, Koh JY. (2000). "A Novel Neuroprotective Mechanism of Riluzole: Direct Inhibition of Protein Kinase C". Neurobiol Dis. 7 (4): 375–383. doi:10.1006/nbdi.2000.0297. PMID 10964608. 
  24. ^ Beal MF, Lang AE, Ludolph AC. (2005). Neurodegenerative Diseases: Neurobiology, Pathogenesis and Therapeutics. Cambridge: Cambridge University Press. p. 775. ISBN 0-521-81166-X. OCLC 57691713. 
  25. ^ Fornai F, Longone P, Cafaro L, et al. (2008). "Lithium delays progression of amyotrophic lateral sclerosis". Proc. Natl. Acad. Sci. U.S.A. 105: 2052. doi:10.1073/pnas.0708022105. PMID 18250315. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=18250315. 
  26. ^ Abramova NA et al. Inhibition by R(+) or S(-) pramipexole of caspase activation and cell death induced by methylpyridinium ion or beta amyloid peptide in SH-SY5Y neuroblastoma. J Neurosci Res. 2002 Feb 15;67(4):494-500.
  27. ^ Gribkoff V and Bozik M. KNS-760704 [(6R)-4,5,6,7-tetrahydro-N6-propyl-2, 6-benzothiazole-diamine dihydrochloride monohydrate] for the treatment of amyotrophic lateral sclerosis. CNS Neurosci Ther. 2008 Fall;14(3):215-26.
  28. ^ [1]
  29. ^ Xia X, Zhou H, Huang Y, Xu Z (Sep 2006). "Allele-specific RNAi selectively silences mutant SOD1 and achieves significant therapeutic benefit in vivo". Neurobiol Dis. 23 (3): 578–86. doi:10.1016/j.nbd.2006.04.019. PMID 16857362. 
  30. ^ Izumi Y, Kaji R (October 2007). "[Clinical trials of ultra-high-dose methylcobalamin in ALS]" (in Japanese). Brain Nerve 59 (10): 1141–7. PMID 17969354. 
  31. ^ Hamadeh MJ, Rodriguez MC, Kaczor JJ, Tarnopolsky MA (Feb 2005). "Caloric restriction transiently improves motor performance but hastens clinical onset of disease in the Cu/Zn-superoxide dismutase mutant G93A mouse". Muscle Nerve 31 (2): 214–20. doi:10.1002/mus.20255. PMID 15625688. 
  32. ^ a b Kasarskis EJ, Berryman S, Vanderleest JG, Schneider AR, McClain CJ (Jan 1996). "Nutritional status of patients with amyotrophic lateral sclerosis: relation to the proximity of death". Am J Clin Nutr. 63 (1): 130–7. PMID 8604660. http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=8604660. 
  33. ^ Slowie LA, Paige MS, Antel JP (Jul 1983). "Nutritional considerations in the management of patients with amyotrophic lateral sclerosis (ALS)". J Am Diet Assoc 83 (1): 44–7. PMID 6863783. 
  34. ^ Pedersen WA, Mattson MP (Jun 1999). "No benefit of dietary restriction on disease onset or progression in amyotrophic lateral sclerosis Cu/Zn-superoxide dismutase mutant mice". Brain Res. 833 (1): 117–20. doi:10.1016/S0006-8993(99)01471-7. PMID 10375685. http://linkinghub.elsevier.com/retrieve/pii/S0006-8993(99)01471-7. 
  35. ^ Zhao Z, Lange DJ, Voustianiouk A, et al. (2006). "A ketogenic diet as a potential novel therapeutic intervention in amyotrophic lateral sclerosis". BMC Neurosci 7: 29. doi:10.1186/1471-2202-7-29. PMID 16584562. 
    Media report on Zhao et al..
  36. ^ "The median survival time from onset to death ranges from 20 to 48 months, but 10 to 20% of ALS patients have a survival longer than 10 years." Prognostic factors in ALS: A critical review published in Amyotrophic Lateral Sclerosis Journal, 05 December 2008, Adriano Chio et al.
  37. ^ "ALS Topic Overview". http://www.webmd.com/brain/tc/Amyotrophic-Lateral-Sclerosis-ALS-Topic-Overview. Retrieved 2008-05-01. 
  38. ^ Vance C, Rogelj B, Hortobágyi T, De Vos KJ, Nishimura AL, Sreedharan J, Hu X, Smith B, Ruddy D, Wright P, Ganesalingam J, Williams KL, Tripathi V, Al-Saraj S, Al-Chalabi A, Leigh PN, Blair IP, Nicholson G, de Belleroche J, Gallo JM, Miller CC, Shaw CE (February 2009). "Mutations in FUS, an RNA processing protein, cause familial amyotrophic lateral sclerosis type 6". Science (journal) 323 (5918): 1208–11. doi:10.1126/science.1165942. PMID 19251628. http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=19251628. Retrieved 2009-03-13. 
  39. ^ Kwiatkowski TJ, Bosco DA, LeClerc AL, Tamrazian E, Vanderburg CR, Russ C, Davis A, Gilchrist J, Kasarskis EJ, Munsat T, Valdmanis P, Rouleau GA, Hosler BA, Cortelli P, de Jong PJ, Yoshinaga Y, Haines JL, Pericak-Vance MA, Yan J, Ticozzi N, Siddique T, McKenna-Yasek D, Sapp PC, Horvitz HR, Landers JE, Brown, RH (Feb 2009). "Mutations in the FUS/TLS Gene on Chromosome 16 Cause Familial Amyotrophic Lateral Sclerosis". Science 323 (5918): 1205-1208. doi:10.1126/science.1166066. 
  40. ^ Reed D, Labarthe D, Chen KM, Stallones R (Jan 1987). "A cohort study of amyotrophic lateral sclerosis and parkinsonism-dementia on Guam and Rota". Am J Epidemiol. 125 (1): 92–100. PMID 3788958. http://aje.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=3788958. 
  41. ^ S. Kuzuhara, Y. Kokubo P3-146Marked increase of parkinsonism-dementia (P-D) phenotypes in the high incidence amyotrophic lateral sclerosis (ALS) focus in the Kii peninsula of Japan. Alzheimer's and Dementia, Volume 2, Issue 3, Pages S417-S417
  42. ^ Spencer PS, Palmer VS, Ludolph AC (Aug 2005). "On the decline and etiology of high-incidence motor system disease in West Papua (southwest New Guinea)". Mov. Disord. 20 (Suppl 12): S119–26. doi:10.1002/mds.20552. PMID 16092101. 
  43. ^ Wicks P, Abrahams S, Masi D, Hejda-Forde S, Leigh PN & Goldstein LH (2005) The Prevalence of Depression and Anxiety in MND, Amyotrophic Lateral Sclerosis and other Motor Neuron Disorders, Volume 6, Supplement 1, p. 147
  44. ^ Rachele MG, Mascia V, Tacconi P, Dessi N, Marrosu F (April 1998). "Conjugal amyotrophic lateral sclerosis: a report on a couple from Sardinia, Italy". Ital J Neurol Sci. 19 (2): 97–100. doi:10.1007/BF02427565. PMID 10935845. 
  45. ^ Poloni M, Micheli A, Facchetti D, Mai R, Ceriani F (April 1997). "Conjugal amyotrophic lateral sclerosis: toxic clustering or change?". Ital J Neurol Sci. 18 (2): 109–12. doi:10.1007/BF01999572. PMID 9239532. 
  46. ^ Camu W, Cadilhac J, Billiard M. (March 1994). "Conjugal amyotrophic lateral sclerosis: a report on two couples from southern France". Neurology 44 (3 Pt 1): 547–8. PMID 8145930. 
  47. ^ Cornblath DR, Kurland LT, Boylan KB, Morrison L, Radhakrishnan K, Montgomery M. (November 1993). "Conjugal amyotrophic lateral sclerosis: report of a young married couple". Neurology 43 (11): 2378–80. PMID 8232960. 
  48. ^ Corcia P, Jafari-Schluep HF, Lardillier D, Mazyad H, Giraud P, Clavelou P, Pouget J, Camu W (November 2003). "A clustering of conjugal amyotrophic lateral sclerosis in southeastern France". Neurol. 60 (4): 553–7. PMID 12707069. 
  49. ^ [2]
  50. ^ [3]
  51. ^ [4]
  52. ^ [5]
  53. ^ [6]
  54. ^ [7]
  55. ^ http://www.uscg.mil/comdt/blog/2009/03/retirement-of-james-f-sloan.asp
  56. ^ [8] (Portuguese)
  57. ^ [9]
  58. ^ http://webmn.alsa.org/site/PageServer?pagename=MN_homepage
  59. ^ [10]

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