Exactly What is ALS Disease
a.k.a. Lou Gehrig's Disease?
Welcome to "ALS Disease" a resource for health information about Lou Gehrig's disease...
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Amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig's disease, is a rapidly progressive, invariably fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles. ALS Disease belongs to a group of disorders known as motor neuron diseases, which are characterized by the gradual degeneration and death of motor neurons.
Other names used when referring to ALS and ALS Disease
Names such as the commonly used term Lou Gehrig's Disease, Charcot Disease (not to be confused with the unrelated Charcot Foot), Amyotrophic Lateral Sclerosis, Motor Neuron Disease, and of course, the popular "ALS" acronym.
What are Motor Neurons, ALS Weakness and ALS Longevity
Motor neurons are nerve cells located in the brain, brainstem, and the spinal cord which act as control units and provide critical communication links between the nervous system and the voluntary muscles of the body. Voluntary messages from motor neurons in the brain (called upper motor neurons) are transmitted to motor neurons in the spinal cord (called lower motor neurons) and from there to the particular muscles involved.
Amyotrophic lateral sclerosis involves both the upper motor neurons as well as lower motor neurons, which degenerate or die, ceasing to send messages to muscles which are not able to function normally. The muscles gradually weaken, waste away (atrophy), and twitch (fasciculations). Eventually, the ability of the brain to start muscle control voluntary movement will be lost, with ongoing fatal outcome decline. Unfortunately, the ALS Disease sufferers longevity and their 5-year survival rate is far from being good news.
ALS causes weakness with a wide range of disabilities (see "What are the symptoms?"). Eventually, all the body muscles under voluntary control are affected, and patients lose their strength and the ability to move their arms, legs, and eslewhere in the body. When muscles in the diaphragm and chest wall fail, patients lose the ability to breathe without ventilatory support. Most people with ALS disease will die from respiratory failure, usually in just 3 to 5-years from disease symptoms onset. However, about 10 percent of ALS patients manage to survive for 10 or more years but only in rare cases.
Although als-disease usually does not effect a person's mind or intelligence, several recent studies suggest some ALS patients may have alterations in cognitive functions such as depression and problems with decision-making and their memory.
ALS does not affect a person's ability to see, smell, taste, hear, or recognize touch. Patients usually maintain control of eye muscles and bladder and bowel functions, although in the late stages of the disease most patients will need help getting to and from the bathroom.
Who gets ALS Disease?
As many as 30,000 or more people in the USA have ALS, with approximately 5,000 diagnosed new cases of ALS-Disease every year. ALS disease is one of the most common neuro-muscular diseases worldwide, and people of all races and ethnic backgrounds are affected. ALS most commonly strikes people from age 40 to 60-years, but younger and older people also may develop ALS-disease. For some unknown reason, men get ALS Disease more frequently than females.
In 90 to 95% of all ALS cases, the disease occurs apparently at random with no clearly associated risk factors. Patients do not have a family history of the disease, and their family members are not considered to be at higher risk for developing ALS.
About 5 to 10% of all ALS cases are inherited. The family or genetic type of ALS-Disease often is from a pattern of disease inheritance requiring just one parent to carry the ALS gene responsible for the disease. About 20-percent of all genetic cases result from a specific genetic defect that leads to mutation of an enzyme known as super-oxide-dismutase-1. Research on this mutation is providing a few clues about the possible causes of motor-neurone death in ALS. Not all familial ALS cases are due to the SOD1 mutation, therefore other unidentified genetic causes are likely.
Symptoms of ALS Disease
The onset of ALS may be so slow or subtle that ALS symptoms are often overlooked. The earliest symptoms may include twitching, cramping, or stiffness of muscles; muscle weakness affecting an arm or a leg; slurred and nasal speech; or difficulty chewing or swallowing. These general complaints then develop into more obvious weakness or atrophy that may cause a physician to suspect ALS.
The parts of the body affected by early symptoms of ALS depend on which muscles in the body are damaged first. In some 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. Some 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. Other patients notice speech problems.
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 have increasing problems with 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 large toe extends upward as the sole of the foot is stimulated in a certain way) 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).
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.
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 ALS-disease patients may experience problems with memory or decision-making, and there is growing evidence that some may even develop a form of dementia. Health care professionals need to explain the course of the disease and describe available treatment options so patients can make informed decisions in advance. In later stages of the disease, patients have difficulty breathing as the muscles of the respiratory system weaken. Patients eventually lose the ability to breathe on their own and must depend on ventilatory support for survival. Patients also face an increased risk of pneumonia during later stages of ALS disease.
What Research is being Done for ALS Disease?
The National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health, is the Federal Government's leading supporter of biomedical research on ALS. The goals of this research are to find the cause or causes of ALS, understand the mechanisms involved in the progression of the disease, and develop effective treatment.
Scientists are seeking to understand the mechanisms that trigger selective motor neurons to degenerate in ALS and to find effective approaches to halt the processes leading to cell death. This work includes studies in animals to identify the means by which SOD1 mutations lead to the destruction of neurons. The excessive accumulation of free radicals, which has been implicated in a number of neuro-degenerative diseases including ALS, is also being closely studied. In addition, researchers are examining how the loss of neurotrophic factors may be involved in ALS. Neurotrophic factors are chemicals found in the brain and spinal cord that play a vital role in the development, specification, maintenance, and protection of neurons. Studying how these factors may be lost and how such a loss may contribute to motor neuron degeneration may lead to a greater understanding of ALS and the development of neuro-protective strategies. By exploring these and other possible factors, researchers hope to find the cause or causes of motor neuron degeneration in ALS and develop therapies to slow the progression of the disease.
Researchers are also conducting investigations to increase their understanding of the role of programmed cell death or apoptosis in ALS. In normal physiological processes, apoptosis acts as a means to rid the body of cells that are no longer needed by prompting the cells to commit "cell suicide." The critical balance between necessary cell death and the maintenance of essential cells is thought to be controlled by trophic factors.
In addition to ALS, apoptosis is pervasive in other chronic neurodegenerative conditions such as Parkinson's disease and Alzheimer's disease and is thought to be a major cause of the secondary brain damage seen after stroke and trauma. Discovering what triggers apoptosis may eventually lead to therapeutic interventions for ALS and other neurological diseases.
Scientists have not yet identified a reliable biological marker for ALS—a biochemical abnormality shared by all patients with the disease. Once such a bio-marker is discovered and tests are developed to detect the marker in patients, allowing early detection and diagnosis of ALS, physicians will have a valuable tool to help them follow the effects of new therapies and monitor disease progression.
NINDS-supported researchers are studying families with ALS who lack the SOD1 mutation to locate additional genes that cause the disease. Identification of additional ALS genes will allow genetic testing useful for diagnostic confirmation of ALS and prenatal screening for the disease. This work with familial ALS could lead to a greater understanding of sporadic ALS as well. Because familial ALS is virtually indistinguishable from sporadic ALS clinically, some researchers believe that familial ALS genes may also be involved in the variations of the more common sporadic form of als-disease. Scientists also hope to identify genetic risk factors that predispose people to sporadic ALS outbreak.
Potential therapy treatments for ALS are being investigated using animals. Some of this promising medical research involves experimental treatment with anti-oxidants. In addition, neurotrophic factors are being studied for their potential to protect motor neurons from pathological degeneration. Investigators are optimistic that these and other basic research studies will eventually lead to treatments for ALS.
Results of an NINDS-sponsored phase III randomized, placebo controlled trial of the drug called minocycline to treat ALS were reported in the past. This study showed patients with ALS disease who received minocycline had a 25% better decline rate vs patients who only received placebo, according to the ALS scale.