Multiple Sclerosis Causes & Risk Factors

Multiple Sclerosis

Multiple sclerosis (MS) is thought to be an autoimmune disease in which the body’s own immune system mistakenly attacks normal tissues of the body. In MS, these attacks are aimed at the myelin in the Central Nervous System (CNS).

The Central Nervous System, which includes the brain and spinal cord, is made up of nerves that act as the body’s messenger system. Each nerve has a fatty covering of myelin that serves as insulation, which helps in the transmission of nerve impulses (messages) between the brain and other parts of the body. Once myelin in a certain area has been damaged, normal nerve function is disturbed and a number of symptoms can be experienced.

Causes & Risk Factors

There has been extensive research about MS over the past 50 years. While we still do not know the cause of MS, we know that it is an inflammatory disorder of the central nervous system that occurs in people with a tendency to such a problem. We know that about 350,000 people in the United States have MS, about one in a 1,000 people. We know that it is more common further north and south of the equator, though we are still unsure why this is. Females tend to get MS about three times as often as males, a rate which is similar to other immune diseases. It is more common in Caucasians, but can occur in other populations. It is not contagious nor is it infectious. There may be a link with reduced vitamin D levels and perhaps with decreased sun exposure.

We know that there is a genetic component to MS. Having a mother or father with MS increases the risk of having MS to about 3-5% lifetime, and having an identical twin with MS increases the risk to about 30%. However, many people with MS have no close family members with the disease.

There is nothing that an individual with MS either did to cause the disease to happen, or can avoid to stop the disease from following its natural course. We know that emotional stress may increase the symptoms of MS. We also know that attacks of MS are more likely after infections. There does not seem to be any association with physical trauma or surgical procedures and MS, nor do these seem to make MS worse.


MS varies from person to person so there is no ‘standard’ set of symptoms for MS. However we know that common symptoms of MS include numbness or tingling in various parts of the body, weakness of one or more parts of the body, walking difficulties, dizziness, fatigue, visual blurring, and occasionally double vision.

Patients may also have a symptom called Lhermitte’s phenomenon, in which they feel electrical tingling or shocks down their back, arms or legs when they bend their neck forwards. Sometimes people notice hesitancy when they try to urinate or may find that 'when they have to go, they have to go’. There is no way to predict which symptoms one person might develop. The usual course of MS is to have periods of time where things are relatively stable, followed by times when, over a few days or weeks, new symptoms occur or old symptoms worsen. This relatively rapid worsening is known as an exacerbation (also known as an attack, or a relapse). In others with MS, there may be a tendency to progress in that symptoms gradually worsen over time (months to years).

Sensory Symptoms

(changes in sensation)

  • Numbness
  • Tingling
  • Other abnormal sensations
  • (“pins & needles,” pain)
  • Visual disturbances
  • Dizziness

Motor Symptoms

(changes in muscle function)

  • Weakness
  • Difficulty walking
  • Tremor
  • Bowel/Bladder problems
  • Poor coordination
  • Stiffness

Other Symptoms

  • Heat sensitivity
  • Fatigue
  • Emotional changes
  • Cognitive changes
  • Sexual symptoms

MS varies from patient to patient so that each individual has their own set of symptoms, problems, and their own course. There are people who have MS so mildly that they never even know that they have it. Of course, there are also others that have it severely. It is really a spectrum that ranges from mild to severe. An international panel of experts developed a classification of MS in 1999 that most neurologists use today.

  • Relapsing-remitting: Patients have attacks of symptoms/signs, with or without recovery, but between attacks have no interval worsening.
  • Secondary progressive: This is often after a few years of relapsing-remitting MS. The pattern changes from a relapsing pattern to progressive in between attacks, usually with fewer attacks.
  • Primary progressive: Gradual onset from the beginning, no attacks.
  • Progressive relapsing: This is a rare form, and begins with a progressive course, while later developing attacks.
  • Fulminant: Very severe, rapidly progressive MS. This is a rare form of MS.

Diagnosis & Testing

Multiple sclerosis is often difficult to diagnose. This is because there is no single test or finding on the examination that makes the diagnosis, and because the disorder varies from person to person. In most cases there is a history of neurological symptoms that come and go over years.

The neurological examination may show changes that suggest problems with the spinal cord or brain. The MRI may show areas of abnormality that suggest MS, though the MRI in itself does not ‘make the diagnosis’. Spinal fluid testing may show that the immune system is active in and around the brain and spinal cord, supporting the diagnosis. Evoked potentials may assist in diagnosis. All of these need to be put together by the physician to determine if MS is the actual diagnosis. Even when all the tests are done, some people cannot be diagnosed for years after the beginning of symptoms.

An international panel of MS experts recently revised the ways that MS is diagnosed, providing a framework for clinicians to use in making the diagnosis. These new diagnostic criteria (The McDonald criteria) allow the diagnosis of MS if MRI scanning shows new lesions forming over time, making even earlier diagnosis possible. Even with these advances, there are some people where the diagnosis may be uncertain for years, due to the complexity and variation of MS.


The Mellen Center staff believes in developing lifetime partnerships with its patients.

At the Mellen Center, patients may meet with one or more members of the care team, depending on individual needs. On the first visit, patients typically meet with a neurologist, who is primarily responsible for managing the patient’s medical care. At future visits, patients will also meet with a clinical nurse specialist or physician assistant, who will discuss any concerns about MS and offer suggestions for special problems related to the disease, including spasticity, pain, bowel, bladder or skin problems. The clinical nurse specialist or physician assistant works closely with the neurologist to carry out the individual’s care plan.

After a thorough medical history and complete physical evaluation, the Mellen Center team develops an individualized care plan to meet the patient’s specific needs. In addition to elements recommended by each member of the Mellen Center team, a care plan also may include specific components requested by the patient, family members or a family doctor.

Follow up visits are scheduled with one of the clinical nurse specialists or physician assistants who will evaluate your current medical status and discuss treatment plans and options with you and one of the Mellen Center physicians. Additional appointments may be scheduled with a physical or occupational therapist, a psychologist, or a social worker, if necessary.

Medical treatments include medications to alleviate symptoms and control the progression of the disease. Experimental therapies involving new drugs also are available. Most of the time, the staff provides treatments in the outpatient setting. Of the 15,000 patient visits annually, only about 150 require hospitalization.

Team members meet regularly to discuss the individual’s progress and fine-tune care plans as needed. Team meetings are an effective means to monitor the flare-ups and remissions that are characteristic of MS. Team members help patients and their families prepare for these changes.

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