Multiple Sclerosis Overview

The name "multiple sclerosis" means that a patient has more than one sclerosis. A sclerosis is a plaque, or hardened tissue. As mentioned in the previous section, people with multiple sclerosis have these plaques, or lesions, in the white matter of the brain or spinal cord. While the gray matter contains neurons (nerve cells), white matter contains the axons (nerve fibers) that connect neurons and allow them to communicate with each other. Specifically, MS means that there has been a breakdown of the myelin sheath, which is the protective layer surrounding the axons. This breakdown is known as demyelinization. When the myelin sheath thins and breaks down, the axon can't function correctly and electrical signals can't travel between the neurons. Although the myelin can rebuild itself, the rate of demyelinization caused by MS is too rapid for it to keep up. In some cases, the axon is cut completely.

This results in numerous neurological symptoms that can appear in the form of attacks. The type, duration and severity of the disease depends on the type of MS. It also varies depending on the person, which can make it difficult for a doctor to determine the type and predict its course.

According to the National Multiple Sclerosis Society, there are four main types of MS:

Progressive-Relapsing - Patients with this rare form of MS get progressively and steadily worse and also suffer attacks, or relapses. Sometimes they recover briefly, but they never experience remission (long-term recovery) of the disease.

Relapsing-Remitting - Most MS patients are diagnosed with this form. They have attacks followed by remissions, during which the disease doesn't get worse.

­Primary-Progressive - A small percentage of MS patients experience a slow progression of the disease without attacks or remissions. They may temporarily improve, or the disease may stay the same for short periods of time.

Secondary-Progressive - Some patients begin with a diagnosis of progressive-relapsing MS but develop secondary-progressive MS. This means that the disease progresses more quickly, and they may or may not experience attacks, periods of recovery or periods of remission. 

­­Multiple sclerosis is one of a class of diseases known as autoimmune diseases. This means that the immune system, which normally defends us against foreign bodies such as viruses and bacteria, attacks the body instead. In MS, T-cells and monocyctes (specialized types of white blood cells) attack the myelin sheaths of the central nervous system. This is why one of the tests for MS is a spinal tap, to check if the cerebrospinal fluid contains an abnormally high number of antibodies and certain protein byproducts (which indicate a breakdown of myelin, composed of protein and lipids).

MS is an extremely unpredictable disease, because the lesions can occur anywhere in the central nervous system and the stages of demyelinization vary depending on the lesion. In the next section, we'll look at the symptoms of MS, and how MS is treated.

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One of the most difficult things about living with multiple sclerosis is its wide range of varying symptoms. Some patients experience every symptom known to be associated with MS; some only experience a few. Some symptoms are chronic and result in permanent damage, while others come and go. While there is no cure, many of the symptoms can be managed through medication and different types of therapy. We'll look at some of the most common symptoms and their typical course of treatment.

Most MS patients experience some degree of fatigue. It tends to get worse over the course of a day and comes on suddenly. Doctors don't currently know why MS causes fatigue. Patients are often prescribed medications such as amantadine, as well as relaxation therapy, stress therapy, and physical therapy to learn energy-saving techniques for tasks like walking.

Vision problems are also very common; a patient may have blurry vision, double vision, tunnel vision, temporary episodes of blindness or severe eye pain. This can be the result of optic neuritis, or lesions on the optic nerves. Steroids can help the patient recover, and these vision problems tend to come and go on their own. MS patients don't usually go completely blind.

Many MS patients also experience numbness and tingling in different parts of the body, such as the arms and legs. If patients have facial numbness, they're advised to be very careful when eating because they can accidentally bite their cheeks or tongue. Doctors sometimes prescribe steroids for numbness as well, but it's another symptom that comes and goes. Some people with MS also experience dizziness and feel off-balance. To help with these symptoms, patients can take drugs for motion sickness, like Dramamine, or antinausea drugs, like Zofran.

MS can be physically painful. Patients can suffer from a number of different types of chronic and acute pain. One chronic type of pain is dysesthesia, which can be burning, itching, tingling and aching pain that some describe as feeling like an electric shock or acid on the skin. It can be treated with antidepressants, which change the central nervous system's reaction to pain. Dysesthesia can also be treated with anticonvulsant medication or nonmedicinal therapies like wearing a body stocking, which can make the pain feel more like pressure. Some patients experience acute pain such as stabbing facial pain, known as trigeminal neuralgia, which can also be treated with anticonvulsants.

Patients who have MS might also have difficulty walking, which can be caused by other common symptoms, such as fatigue, numbness and vertigo. Walking problems can also result from weak muscles or spasticity, which occurs when the muscles stiffen and contract involuntarily. Depending on the cause, medications can help. Some patients who have problems walking use canes or walkers, or must progress to scooters or wheelchairs as the disease worsens. Physical therapy can also help to stretch spastic muscles and teach ways of walking that compensate for the weakness.

Since MS originates in the central nervous system, it can also affect brain functions such as memory, organization, problem-solving and speech. While half of MS patients will develop some kind of problem with higher brain function, only 5 to 10 percent have severe impairment. [source: NMSS]. MS also affects the brain in other ways. Many patients become clinically depressed, either as a reaction to the disease or from the demyelinization. Depression can also be a side effect of some of the drugs prescribed to treat other symptoms.

In addition to treating the symptoms of MS, doctors also prescribe drugs to help slow the progress of relapsing forms of the disease and decrease its activity. These are known as disease-modifying agents. The FDA has currently approved five different drugs for this purpose: Avonex, Betaseron, Caopaxone, Novantroe, Rebif and Tysabri. These drugs either suppress or alter the immune system in some way, and all have different side effects, so which one gets prescribed depends entirely on the individual.

Currently, there are about 400,000 people living with multiple sclerosis in the United States, and more than 2 million people throughout the world. There's about a 1 in 750 chance of being diagnosed with it [source: NMSS]. But researchers don't yet know exactly what causes MS, or what makes some people more susceptible to it. It's often called the "prime of life" disease, because that's when people are usually diagnosed. The first attack often occurs when the patient is between the ages of 20 and 50, although it and subsequent attacks may not be recognized as MS until much later. Multiple sclerosis isn't contagious and doesn't appear to be directly hereditary, although the risk for people with parents, siblings or children who are diagnosed with it is somewhere between 1 in 20 and 1 in 40 [source: Robinson].

­Women are diagnosed more than twice as often as men (which is true of nearly all autoimmune diseases). This usually occurs when the production of estrogen and progesterone, the female sex hormones, are at their peak. Because of this, researchers are looking at what roles estrogen and progesterone may play in the development of MS.

Caucasians, especially those of Northern European descent, are more likely to get MS than any other ethnicity. People who live north of the equator are diagnosed with MS more often than people living south of the equator. Some researchers think that the latter's increased exposure to the sun may somehow protect them. Others have also suggested that there are "clusters" of MS -- areas where a high number of people have been diagnosed with the disease. Although there have been studies in some of these areas, they have not yet found any reason for the "cluster," and many argue that the idea of "clusters" themselves is questionable.

The latest target in the search for a cause is the environment -- this doesn't mean the natural environment, but something outside of the human body. It could be anything from reactions to chemicals and toxins that we're exposed to on a daily basis, our increased stress levels, our diet, or other illnesses. Exposure to heavy metals like lead, for example, can cause neurological problems. Some believe that the typical Western diet, high in saturated fats, could be a factor. However, there's no evidence that these factors lead to MS. Some researchers think that the immune system is simply overburdened by everything that it has to fight on a daily basis. Its breakdown, they believe, has led to an increase in autoimmune diseases like multiple sclerosis.

Although there are arguments for all of these potential causes, the distribution of MS suggests that it's likely a complex combination of genetics and environment. So far, scientists have identified two genes that can increase the risk of developing MS. When it comes to the search for a cause, however, it's still in the beginning stages. From the future to the past: In the next section, let's take a look at the history of multiple sclerosis.

Like many other diseases, multiple sclerosis existed long before it had a name. Writings from as far back as the Middle Ages described patients with symptoms that doctors today believe pointed to MS. A Dutch saint named Lidwina, who died in 1433, may have been one of the first known MS patients. After she fell while ice skating, she developed symptoms such as excruciating pain, blinding headaches, problems walking and paralysis. Her condition got worse over the course of her life, but she did have remissions. Another well-known potential MS patient was a grandson of King George III, who described his symptoms in a diary that he kept until his death in 1848.

Twenty years later, Dr. Jean-Martin Charcot became the first person credited with identifying multiple sclerosis as a disease. A female patient of his suffered an unusual combination of symptoms. He tried some of the typical treatments for other neurological disorders, such as electrical stimulation and injections of silver (which helped alleviate the symptoms of syphilis), but none of them worked. After his patient died, he dissected her brain and discovered the brain lesions. He called the disease sclerose en plaques. Myelin was discovered shortly afterwards, although its exact significance was unknown.

Improvements in microscopes helped doctors in the search to understand the disease. In 1916, a Scottish doctor named James Dawson was able to clearly describe the inflammation and demyelinization after viewing brain cells of patients with MS through a microscope. At the time, doctors thought that MS was caused by a toxin or virus that made its way into the brain via the bloodstream, although they had no proof for either. In the 1930s, laboratory studies in mice suggested the possibility that the immune system was involved, but most doctors didn't take it seriously.

­­In 1947, a researcher at Columbia University found that people with MS had unusual protein byproducts in their cerebrospinal fluid, paving the way for today's MS testing. During this time, doctors believed that MS was caused by problems with blood flow and tried to stimulate circulation for treatment. After DNA's structure was discovered in 1953, doctors began to better understand both genetics and the immune system. The 1960s resulted in the discovery that MS was probably an autoimmune disease, and in the next decade, steroids were used to treat attacks. Scientists also developed the first disease-modifying agent.

Numerous clinical trials involving potential treatments and diagnostics took place in the 1980s and 1990s. MRI scans became the standard for diagnostics as well as testing the effectiveness of disease-modifying agents in slowing down the progress of the disease. There were also improvements in the use of drugs to treat symptoms, as well as the development of more effective rehabilitation and other types of therapies. Unlike MS patients of the past, patients of today have a wide range of treatment options. Recently, there has been promising clinical research in the form of stem cell treatments, which may be able to repair damaged myelin.

To learn more about multiple sclerosis and related topics, try the links to articles on the next page.