What is Multiple Sclerosis?

MS is thought to be an autoimmune disease that affects the central nervous system (CNS). The CNS consists of the brain, spinal cord, and the optic nerves. Surrounding and protecting the nerve fibers of the CNS is a fatty tissue called myelin, which helps nerve fibers conduct electrical impulses.

In MS, myelin is lost in multiple areas, leaving scar tissue called sclerosis. These damaged areas are also known as plaques or lesions. Sometimes the nerve fiber itself is damaged or broken.

Myelin not only protects nerve fibers, but makes their job possible. When myelin or the nerve fiber is destroyed or damaged, the ability of the nerves to conduct electrical impulses to and from the brain is disrupted, and this produces the various symptoms of MS.

People with MS can expect one of four clinical courses of disease, each of which might be mild, moderate, or severe.

• Relapsing-Remitting
  Characteristics: People with this type of MS experience clearly defined flare-ups (also called relapses, attacks, or exacerbations). These are episodes of acute worsening of neurologic function. They are followed by partial or complete recovery periods (remissions) free of disease progression.
  Frequency: Most common form of MS at time of initial diagnosis. Approximately 85%.

• Primary-Progressive
  Characteristics: People with this type of MS experience a slow but nearly continuous worsening of their disease from the onset, with no distinct relapses or remissions. However, there are variations in rates of progression over time, occasional plateaus, and temporary minor improvements.
  Frequency: Relatively rare. Approximately 10%.

• Secondary-Progressive
  Characteristics: People with this type of MS experience an initial period of relapsing-remitting MS, followed by a steadily worsening disease course with or without occasional flare-ups, minor
• recoveries (remissions), or plateaus.
  Frequency: 50% of people with relapsing-remitting MS developed this form of the disease within 10 years of their initial diagnosis, before introduction of the "disease-modifying" drugs. Long-term data are not yet available to demonstrate if this is significantly delayed by treatment.

• Progressive-Relapsing
  Characteristics: People with this type of MS experience a steadily worsening disease from the onset but also have clear acute relapses (attacks or exacerbations), with or without recovery. In contrast to relapsing-remitting MS, the periods between relapses are characterized by continuing disease progression.
  Frequency: Relatively rare. Approximately 5%.

What Causes MS?

While the exact cause of MS is unknown, most researchers believe that the damage to myelin results from an abnormal response by the body’s immune system. Normally, the immune system defends the body against foreign invaders such as viruses or bacteria. In autoimmune diseases, the body attacks its own tissue. It is believed that MS is an autoimmune disease. In the case of MS, myelin is attacked. Scientists do not yet know what triggers the immune system to do this. Most agree that several factors are involved, including:

• Genetics
• Gender
• Environmental Triggers
  [Possibilities include viruses, trauma, and
  heavy metals ( toxicology)]

Who Gets MS?

Anyone may develop MS, but there are some patterns.

• Most people with MS are diagnosed between the ages of 20 and 50.
• Two-three times as many women as men have MS.
• Studies indicate that genetic factors make certain individuals more susceptible than others, but there is no evidence that MS is directly inherited.
• MS occurs more commonly among people with northern European ancestry, but people of African, Asian, and Hispanic backgrounds are not immune.

Approximately 400,000 Americans acknowledge having MS, and every week about 200 people are diagnosed. Worldwide, MS may affect 2.5 million individuals.

Symptoms

Symptoms of MS are unpredictable and vary from person to person and from time to time in the same person. For example, one person may experience abnormal fatigue, while another might have severe vision problems. A person with MS could have loss of balance and muscle coordination making walking difficult; another person with MS could have slurred speech, tremors, stiffness, and bladder problems. While some symptoms will come and go over the course of the disease, others may be more lasting.

As a result of the inflammatory, demyelinating process in the central nervous system, people with MS can experience a wide variety of symptoms. The most common symptoms of MS include:

• Fatigue (also called MS lassitude to differentiate it from tiredness resulting from other causes)
  
• Problems with walking
  
• Bowel and or bladder disturbances
  
• Visual problems
  
• Changes in cognitive function, including problems with memory, attention, and problem-solving
  
• Abnormal sensations such as numbness or "pins and needles"
  
• Changes in sexual function
  
• Pain
  
• Depression and/or mood swings
  

Less common symptoms include:

• Tremor
  
• Incoordination
  
• Speech and swallowing problems
  
• Impaired hearing
  

All of these are considered primary symptoms of MS because they are a direct result of demyelination, the destruction of myelin—the fatty sheath that surrounds and insulates nerve fibers in the central nervous system—and of damage to the nerve fibers themselves. Demyelination and neuronal damage impair transmission of nerve impulses to muscles and other organs, resulting in impaired function. Many of these symptoms can be managed effectively with medication, rehabilitation, and other management strategies.

In addition to the primary symptoms caused by demyelination, there are other types of problems or complications that can occur as indirect results of the primary symptoms or the experience of having a chronic illness:

Secondary symptoms of MS are complications that can arise as a result of the primary symptoms. For example, bladder dysfunction can cause repeated urinary tract infections. Inactivity can result in loss of muscle tone and disuse weakness (not related to demyelination), poor postural alignment and trunk control, decreased bone density (and resulting increased risk of fracture), and shallow, inefficient breathing. Immobility can lead to pressure sores. While secondary symptoms can be treated, the optimal goal is to avoid them by treating the primary symptoms.

Tertiary symptoms of MS are the social, vocational and emotional complications associated with the primary and secondary symptoms. The diagnosis of a chronic illness can be damaging to self-esteem and self-image. A person who becomes unable to walk or drive may lose his or her livelihood. The strain of dealing with a chronic neurologic illness may disrupt personal relationships. People with MS frequently experience emotional changes as well, but it is important to note that mood swings and depression can occur as primary, secondary, or tertiary symptoms of the disease. Professional assistance from psychologists, social workers, physical and occupational therapists, and public health agencies is indicated for managing many of these psychosocial and vocational issues.

It is important to remember that not every person with MS experiences all of these symptoms. Some people may experience only one or two of them over the course of the disease, while others experience quite a few. Symptoms can come and go quite unpredictably, and no two people experience them in exactly the same way. Most of the symptoms of MS can be effectively managed, and complications avoided, with regular care by a neurologist and allied health professionals.

Diagnosis of MS

At this time, no single test is available to identify or rule out MS. Several tests and procedures are needed. These are likely to include:

Complete Medical History
Healthcare providers need an overall view of the individual's health picture, including symptoms and when they began.

Nervous System Functioning
Testing of reflexes, balance, coordination, and vision— as well as checking for areas of numbness

Diagnostic Tests such as:

* MRI scan, which gives detailed view of the brain
* Evoked potential tests, which measure how quickly and accurately a person's nervous system responds to certain stimulation
* Spinal tap, which checks spinal fluid for signs of the disease

Two Basic Signs are Required to Confirm MS
1. Signs of disease in different parts of the nervous system
2. Signs of at least two separate flare-ups (also called relapses or exacerbations) of the disease

Information provided by the National MS Society