MS is an unpredictable disease of the nervous system which manifests itself primarily through disorders in mobility. It is associated with a variety of other symptoms and complications. The most important fact about multiple sclerosis is its unpredictability and its uncertainty. There are very few certainties to be found anywhere in any aspect of this disease.
Multiple sclerosis is a demyelinating disease of the white matter of the central nervous system. Gray matter consists primarily of nerve cells. Axons (nerve fibers) are the connections between the cell body and the muscles, sensory organs, and primary organs such as the heart. These nerve cells are the communication system both within the central nervous system and between it and the rest of the body. Axons are sheathed in myelin, a white substance (hence the term "white matter") that insulates them and speeds transmission of impulses along the cell fibers. Electrical impulses move along the nerve fiber to the synapse (the connection point between cells) to the next nerve cell.
The lesions or plaques of multiple sclerosis are areas of tissue damage arising from inflammation, which occurs when white blood cells and fluid accumulate around blood vessels. This inflammation causes destruction of myelin. After the fragments are cleared away, a scar is formed in the area which is the lesion, or area of demyelinization. These lesions impede conduction of signals by blocking or slowing communication, either completely or partially and from time to time. The process can be thought of as similar to an electrical short circuit. The symptoms of multiple sclerosis result from this loss in signal conduction.
MS is the most common demyelinating disease of the central nervous system. In the United States alone, there are at least 250,000 cases. For reasons that remain unclear, it is more prevalent in northern temperate zones and affects noticeably more women than men. The average age of onset is thirty years.
Studies indicate that an environmental factor, perhaps exposure to a virus, when combined with a genetic predisposition to the disease, may well dictate occurrence of the disease. MS is not a genetically transmitted disease; it may be an autoimmune disease, with some part of the body attacking itself.
Diagnosis
Diagnosis of MS is difficult. A medical history and clinical examination must show at least two separate lesions that have occurred at more than one time. Obviously, any other possible causes must be ruled out. Because of the difficulty of diagnosis, the presence of MS is usually deemed to be either definite, probable, or possible. There is no one specific diagnostic test that can either confirm or rule out its presence.
A neurological examination can indicate lesions through the presence or absence of various signs and reflexes. Computerized tomographic (CT) scans will show some lesions. Magnetic resonance imaging (MRI) usually reveals many more lesions than the CT scan, including some that may be subclinical, that is, they are not detectable through examination and may have no associated symptoms. An autopsy will usually show many more lesions than were suggested by either symptoms or signs. These lesions are probably the result of subclinical attacks of the disease.
Brain wave testing (evoked potentials) of responses to various forms of stimulation of the eyes, ears, or other parts of the body may demonstrate delays in these responses and indicate lesions that are clinically silent (producing no symptoms) and can sometimes firm up a questionable diagnosis from probable to definite MS. Testing of the cerebrospinal fluid (CSF) for protein content, the number and type of white blood cells, and the amount of IgG, a gamma globulin, can also support a diagnosis. An old diagnostic technique is to see whether a person becomes worse after a hot bath.
Symptoms
Symptoms of MS vary enormously, both from patient to patient and, over time, in one patient. There are three primary courses the disease may take:
- a benign course, involving a few early mild attacks followed by almost complete remission, leaving little or no disability (30%)
- an exacerbating remitting course with more early attacks with less complete remission resulting in some disability, followed by long periods of stability (40%)
- a progressive course involving a slow and continuing progression of the disease with no remission (30%)
Some of those with an exacerbating remitting course will eventually develop a slow progression involving fewer and less complete remissions with cumulative disabilities. Very rarely, there is a rapidly progressive course leading to death. MS itself is almost never the cause of death; death results from accompanying complications or infections. Generally speaking, the life expectancy of those with MS is at least 75% of normal.
Exacerbations and remissions are difficult to define. An exacerbation is an
acute appearance of new symptoms or worsening of old symptoms which lasts at least 24 hours, while a remission is a total or more often partial clearing of symptoms and signs which lasts more than 24 hours.
Symptoms may appear very rapidly, within minutes or days, or very slowly, over a period of weeks. They may be very transient and come and go rapidly. New symptoms may accumulate; old symptoms may reappear and/or intensify. Exacerbations, episodes of new disease activity, are not easy to diagnose with certainty. New symptoms may result from old, not new, areas of disease that were previously silent. Conversely, recurrence of old symptoms is not a sure indication of lack of exacerbation. Over time, the disease process may result in the formation of new plaques or the enlargement of existing ones. Exacerbations can be caused by heat, physical trauma, extreme fatigue, psychological stress, infections, or any other kind of stress. While all of these factors have been associated with exacerbations, there is little empirical data to support these associations.
There does seem to be a direct correlation between the degree of remission from an exacerbation and its duration. For example, 85% will usually improve spontaneously from an exacerbation that lasts one week, but only 7% will improve after an exacerbation lasting one to two years. Over time, a series of exacerbations and remissions may result in a gradual accumulation of irreversible changes and disability.
There are factors that may be predictive of the course of the disease. An earlier age at onset may mean a more
benign course. If, at onset, symptoms are sensory, the course of the disease may be less severe, while motor symptoms (weakness or poor coordination) at onset may be predictive of greater disability. Again, as with everything to do with this disease, variation is extreme and the course and progression of the disease is unpredictable.
TreatmentThere is no cure for multiple sclerosis. There are claims that the number or degree of exacerbations can be reduced and that life expectancy can be extended. Many promising modes of treatment are being developed and tested but most remain experimental. An enormous amount of research is currently being done on the causes and processes of
multiple sclerosis, and understanding of the disease continues to increase.
Here is an article that suggests infection with parasites may have a protective effect against MS relapses. A steady rise in
autoimmune diseases such as multiple sclerosis (MS) has been noted in recent decades, and environmental factors could be the cause of this increase. One theory, similar to the "hygiene hypothesis" in which an excessively germ-free environment may contribute to an increase in
allergies, holds that a decline in infectious diseases may play a role in increasing autoimmune disease incidence. The first study examining the relationship between
parasite infections and MS in humans suggests that such infections may affect the immune response in a way that alters the course of MS.
Previous studies involving animals have shown that parasite infection can influence the course of
autoimmune diseases. These studies suggest that individuals with parasite infections have a diminished T cell response when unrelated
antigens (foreign substances that generate an immune response) are present. The current study, conducted by Jorge Correale, M.D., and Mauricio Farez, B.Sc., of the Raúl Carrea Institute for Neurological Research in Buenos Aires, Argentina, involved 12 patients with MS who also had a
parasite infection, 12 controls with MS who were uninfected, and 12 healthy individuals. The two groups of MS patients had a similar disease course. Patients had a neurological exam every three months and a brain
MRI every 6 months, while immunological evaluations were conducted during the last 12 to 18 months of the study. Patients were followed for an average of 4.6 years.
During the study period, there were three clinical relapses of MS in the infected group and 56 relapses in the uninfected group. Only two infected patients showed minimal Expanded Disability Status Score changes (EDSS is used to measure disability due to MS) that lasted less than three months, while the other 10 had no changes in EDSS scores. In the uninfected group, 11 patients showed an overall increase in EDSS. Since MS involves an inflammatory response associated with the production of certain regulatory
proteins known as
cytokines, the number of cells producing
cytokine suppressants was measured and found to be significantly higher in infected patients.
Because
parasites inhabit their hosts for long periods of time, they can develop molecules that generate strong
anti-inflammatory responses, which enhance their survival. Further investigation is warranted in order to identify which molecules cause
immune system effects that dampen the inflammatory reactions normally seen in
autoimmune diseases, the authors note. They conclude that "induction of a regulatory
anti-inflammatory network generated by persistent
parasite infections may offer a potential explanation for environment-related suppression of MS development in areas with low disease prevalence."[
"Association Between Parasite Infection and Immune Responses in MS," Jorge Correale, Mauricio Farez, Annals of Neurology, January 2007]
Researchers have found a promising new treatment that may be successful in slowing or stopping the progress of multiple sclerosis. The discovery, called the "
DNA Vaccine" was developed without using any embryonic stem cells.
According to the report by Citizen Link, the treatment works by manipulating a person's DNA, so it will reduce the attack on the "protective coating" around nerve fibers in the brain - which is caused by MS.
Dr. Amit Bar-Or explained, "The idea of these DNA-vaccine approaches would be to modulate or suppress just those cells that you might consider the bad guys cells, while sparing the rest of the immune system."
"Unethical science tends to be a poisoned fruit," added David Prentice, senior fellow for life sciences at Family Research Council. "You don't need to go that direction. The adult stem cells and these other nonembryonic types of treatments are the ones where the real success happens." (August 16, 2007)