Multiple Sclerosis
What is "multiple sclerosis"?
What it means is that there is a neurological deficit that occurs in the central nervous system which is made up of the eye, the brain and the spinal cord. So it is a central nervous system disease. The major defect is the loss of myelin due to an immune attack. So lymphocytes into the brain which ordinarily don't have lymphocytes in them. There are no lymphoid tissue or draining lymph nodes in the brain. And the lymphocytes enter the brain because the blood brain barrier will not keep out an activated lymphocyte. So it gets activated somewhere in the periphery in the blood and it enters the brain and it attacks the white matter.
What are the symptoms of multiple sclerosis?
So if multiple sclerosis attacks areas of the brain that don't have an obvious function, you don't see anything. But if it attacked the spinal cord, you would see something because it's a small area, it's vital and you would probably have weakness or numbness or something of that sort. If it attacked the optic nerve, vital. You certainly would have difficulty with your vision. If it's in the brain stem, it's going to be vertigo or double vision. If it's in the spinal cord, it's going to be weakness of the legs and having some bladder symptoms or some numbness in their legs. If it's in the neck, it may be numbness or weakness of a hand. If it's in the cerebellum, it's going to be a patient who has trouble with their coordination.
What are the causes of multiple sclerosis?
Most sufferers of multiple sclerosis (MS) contract it before the age of 15. Migration studies after World War II suggested that if you migrate as a child of under 15 years of age, you will suffer from the MS of the area you're migrating to. If you migrate at the age of 15, you'll suffer from the MS of where you're migrating from. So there's a suggestion that there's a cut-off age. You may not contract the disease for 3 years. But it seems to be something that you contract before age 15. The most likely environmental trigger is an infection because over the last 6 years almost everything else has changed and the MS disease really has not changed very much, the prevalence of MS is not very different. To provide an example, lead levels have gone up. There have been different nutritional issues that have come up. There are different medicines on the market and so forth, and different toxins in the environment. That doesn't seem to really make a major impact. However, the virus infections have not changed and therefore we think that it's probably a virus or many viruses. The virus that seems to have the best supporting evidence is the Epstein-Barr virus. Some work had been carried out on that. But it's hard to prove it as the cause of the disease, what we are studying is, "Is it the trigger of the disease?" In other words, what triggers multiple sclerosis? We don't know that yet.
How common is multiple sclerosis?
There are probably 400,000 people with MS in the United States. There are probably close to 3 million worldwide. Multiple sclerosis is a very, very rare disease among Asians. There is an MS in Asians, but it's not quite like the MS in the Northern Europeans. It is not known in Africa, but it is in African Americans. It's a predominantly female disease, although males get it obviously. We don't know the basis of that. But all autoimmune diseases are more common in women than in men.
Who is most at risk for developing multiple sclerosis?
We don't know who is most at risk from developing multiple sclerosis (MS). We think there is a genetic susceptibility. There are some ethnic background issues, people of Northern European extraction have more MS. The largest focus of MS is in Scandinavia. The Vikings got around, so they may have contributed. There are also geographic considerations. People who come from the Mediterranean, or from the south, even in our country, have less MS. And there's no question that those people who are north get less sun than the people who are south. I think that the issue really relates to "Why is that?". The only factor that you can think of is UV light. That's something that is really tantalizing. We talked a little bit about the hygiene theory. There's no question that the more middle class you are, the more affluent you are; the more susceptible you are to MS. So what is the reason? If the reason is an infectious trigger, you're being protected by your hygiene. And that actually is a theory of MS; the reason for these kinds of people - the northern European people, is not just their genetic susceptibility, but they happen to be people very orientated towards being clean. It is predominantly female. The peak age group is probably around thirty, however we are seeing it in children; there are children now that have been diagnosed with it in this country, and we are diagnosing it in people who are forty, fifty, and sixty years of age because of improved techniques like MRI and so forth.
What are the risk factors for multiple sclerosis?
People with multiple sclerosis have a normal life expectancy. The quality of life is the real issue. I think that the earlier you treat MS patients, the less likely that they're going to get into trouble. It is a sword over their head. I have had patients who have had MS for 50 years, and they're still functional. They still work., and they'll tell me that some mornings, they wake up and they wonder what's going to happen to them. And I tell them, "You're probably going to die of a heart attack before your MS gets you." But they still think about, "Well, maybe I will be paralyzed, or maybe I won't be able to see, or maybe this will happen." Even though they've been living with it for 40 or 50 years, they still have that fear factor. That's almost impossible to eliminate in somebody with a chronic illness.
