Amyotrophic lateral sclerosis, or ALS, is also called Lou Gehrig's disease in memory of the Yankee baseball player who suffered from this disorder. According to Allan Ropper, M.D., Professor of Neurology at the Harvard Medical School in "Adams & Victor's Principles of Neurology," the disease affects approximately one person in every 100,000. It is a fatal disease. Fifty percent of people with ALS die within three years, and 90 percent die within six years.
What Is It?
ALS is a disease where the motor neurons of the brain stem and spinal cord deteriorate. Motor neurons are the nerves that send signals to your muscles. Catherine Lomen-Hoerth, M.D., Ph.D., Director of the ALS Center at the University of California writes in "Pathophysiology of Disease" that physicians do not yet know what causes ALS. They have determined that approximately 10 percent of ALS cases affect people who are in the same family.
Symptoms
The symptoms initially will be a weakness in one hand or foot. It will be hard to do things with the fingers, such as buttoning clothes or putting a key in the door or car ignition. As the disease progresses, people have twitching and cramping in the muscles of their arms and shoulders. They start to develop cramps in their legs. And then they will have the same problem in the other arm and leg. Eventually, their arms may just dangle because they cannot use them. They will become weak in their neck, then chest and lower body.
Diagnosis
An electromyograph, or EMG, is used to record the electrical activity of a muscle. Ropper explains in "Adams & Victor's Principles of Neurology" that the EMG of a person with ALS will show that the nerves are degenerating. He advises that to make the diagnosis of ALS, physicians should see degeneration in at least three limbs. A biopsy of the muscle can be performed to confirm the diagnosis. Nerve conduction studies, or studies of how the nerves are sending their signals, will show a progressively smaller signal as the disease develops.
Treatment
In "Adams & Victor's Principles of Neurology," Ropper writes that a medication called riluzole has been shown to slow the development of ALS. But the best that it can do is to add three months of life. Baclofen or tizanidine are two medications used to decrease muscle spasms. Physical therapy is recommended for these patients. Bilevel positive airway pressure, or BiPAP, and CoughAssist are two types of breathing machines that can help people with ALS. As the disease progresses, patients will require a cane, then a walker, then a wheelchair, and finally a feeding tube and mechanized bed.
Recent Studies
One study that Lomen-Hoerth writes about in "Pathophysiology of Disease," describes how ALS may involve a change in a substance called glutamate, which is used by the nerves to send signals. Another study has found a mutation in an enzyme called superoxide dismutase, or SOD1. The mutation in SOD1 causes substances to accumulate, which may be toxic to the nerves. Other studies are looking at the role of proteins in ALS, especially a protein called TDP 43, which has only recently been discovered.
References
- "Adams & Victor's Principles of Neurology"; Allan Ropper, M.D., Martin Samuels, M.D.; 2009
- "Pathophysiology of Disease: An Introduction to Clinical Medicine"; Stephen McPhee, M.D., Gary Hammer, M.D., Ph.D.; 2010
