What is ALS?
Amyotrophic lateral sclerosis (ALS), often referred to as "Lou Gehrig's disease," is a progressive neurodegenerative disease that attacks nerve cells in the brain and the spinal cord. Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually lead to their death. When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost. With all voluntary muscle action affected, patients in the later stages of the disease become totally paralyzed. Yet, through it all, for the vast majority of people, their minds remain unaffected.
A-myo-trophic comes from the Greek language. "A" means no or negative. "Myo" refers to muscle, and "Trophic" means nourishment---"No muscle nourishment." When a muscle has no nourishment, it "atrophies" or wastes away. "Lateral" identifies the areas in a person's spinal cord where portions of the nerve cells that nourish the muscles are located. As this area degenerates it leads to scarring or hardening ("sclerosis") in the region
As motor neurons degenerate, they can no longer send impulses to the muscle fibers that normally result in muscle movement. Early symptoms of ALS often include increasing muscle weakness, especially involving the arms and legs, speech, swallowing and breathing. When muscles no longer receive the messages from the motor neurons that they require to function, the muscles begin to atrophy (waste away). Limbs begin to look "thinner" as muscle tissue atrophies.
The body has many kinds of nerves. There are those involved in the process of thinking, memory, and of detecting sensations (such as hot/cold, sharp/dull), and others for vision, hearing, and other bodily functions. The nerves that die when you have ALS are the motor neurons that provide voluntary movements and muscle power. Examples of voluntary movements are your making the effort to reach for the phone or step off a curb; these actions are controlled by the muscles in the arms and legs.
The heart and the digestive system are also made of muscle but a different kind, and their movements are not under voluntary control. When your heart beats or a meal is digested, it all happens automatically. Therefore, the heart and digestive system are not involved in ALS. Breathing also may seem to be involuntary. Remember, though, while you cannot stop your heart, you can hold your breath - so be aware that ALS may eventually have an impact on breathing.
Although the cause of ALS is not completely understood, the 1990's have brought a wealth of new scientific understanding regarding the physiology of this disease.
Perspective from Hiroshi Mitsumoto, M.D., Cleveland Clinic ALSA Center and Chair of ALSA's Medical Advisory Committee: "In a review of ALS published in the Archives of Neurology in 1988, I quote Lewis Thomas. 'The whole field of biomedical science is on the move as never before in the long history of medicine. I don't know what will happen over the next 20 years, but my guess is that we are on the verge of discoveries that will match the best achievement in infectious disease a generation ago.' In ten years - just half of Lewis' prediction - we now know the gene responsible for some familial ALS; we have the first drug we can prescribe for ALS; we have a real animal model for this disease and we have incredibly important knowledge on the cell death mechanisms of motor neurons in ALS. Yes, the progress still appears to be too slow for anyone waiting for a breakthrough, but we are truly on the verge of more exciting discoveries. We have solid reasons for strong hope in ALS." There is no question about whether the cause of ALS will be found; it is only a question of when.
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