Multiple sclerosis (MS)
Multiple sclerosis (MS) is a chronic, sometimes disabling, disease of the
central nervous system affecting between 350,000 and 500,000 people in the
U.S. according to the Multiple Sclerosis Society. If affects twice as many
women as men. MS develops more often in Caucasians than in other races.
About 200 new cases of MS are diagnosed in the U.S. every week.
The cause of MS is still unknown. Some researchers believe it could be
caused by a virus, although it is unlikely that there is just one virus
responsible for triggering the condition. Researchers do know that MS is not
contagious. And while it is not an inherited disease, genetic susceptibility
plays a role. There is a higher risk for MS in families where it has already
occurred. The average person in the U.S. has about a two in 1,000 chance of
developing MS. Children or siblings of a person with MS have a four in 1,000
chance of developing the disease if they're female; and a two in 1,000
chance if they're male.
It is believed that MS is an autoimmune disease. In MS, the immune system -
for reasons still not understood -- attacks and destroys myelin and the
oligodendrocytes (oligo-few, dendro-branches, cytes-cells) that produce it.
Though the body usually sends in immune cells to fight off bacteria and
viruses, in MS they misguidedly attack the body's own healthy nervous
system, thus the term autoimmune disease. Rheumatoid arthritis and lupus are
other types of autoimmune diseases.
In multiple sclerosis, these misdirected immune cells (certain types of
lymphocytes, T-cells and killer cells) attack and consume myelin, damaging
the myelin sheath -- the fatty insulation surrounding nerve cells in the
brain and spinal cord. Myelin acts like the rubber insulation found in an
electric cable and facilitates the smooth transmission of high-speed
messages between the brain and the spinal cord and the rest of the body. As
areas of myelin are affected, messages are not sent efficiently or they
never reach their destination.
Eventually there is a build up of scar tissue (sclerosis) in multiple places
where myelin has been lost; hence the disease's name: multiple sclerosis.
These plaques or scarred areas, which only are a fraction of an inch in
diameter, can interfere with signal transmission. The underlying nerve also
may be damaged, further worsening symptoms and reducing the degree of
recovery experienced. The disease can manifest itself in many different
ways. Sometimes the diseased areas cause no apparent symptoms and sometimes
they cause many; this is why the severity of problems varies greatly among
persons affected with MS.
Multiple sclerosis usually strikes in the form of attacks or exacerbations.
This is when at least one symptom occurs, or worsens, for more than 24
hours. The symptom(s) can last for days, weeks, months or indefinitely.
The most common type of multiple sclerosis is relapsing-remitting MS. It is
characterized by periods of exacerbation followed by periods of remission.
The remissions occur because nervous system cells have ways of partially
compensating for their loss of ability. There's no way to know how long a
remission will last after an attack - it could be a month or it could be
several years. But disease activity usually continues at a low, often almost
indiscernible level, and MS often leads to disability over time as the
signal-transmitting portion of the cells - the axons - are damaged.
Most commonly, multiple sclerosis starts with a vague symptom that
disappears completely within a few days or weeks. Temporary weakness in a
limb can be a first sign. Ataxia (general physical unsteadiness), temporary
blurring or double vision, difficulty urinating and slurred speech are also
symptoms which can appear suddenly and then vanish for years after the first
episode, or in some cases never reappear.
The symptoms of MS vary greatly, as does their severity, depending on the
areas of the central nervous system that are affected. Most people suffer
minor effects. The disease can, however, completely disable a person,
preventing him or her from speaking and walking in the most extreme cases.
The bodily functions that are commonly affected by MS are:
- vision
- coordination
- strength
- sensation
- speech and swallowing
- bladder and bowel control
- sexuality
- cognitive function (thinking, concentration and short-term memory)
A varying degree of dysfunction may occur within these general areas. For
instance, one person may suffer blurred vision while another may suffer
double vision. Or one person may suffer from tremors while another will
experience clumsiness of a particular limb.
Specific symptoms associated with MS can include:
- Fatigue: a debilitating kind of general fatigue that is unpredictable and out of proportion to the activity; fatigue is one of the most common (and
- one of the most troubling) symptoms of MS
- Cognitive function: short-term memory problems and difficulty concentrating and thinking, but typically not severe enough to seriously interfere with daily functioning for most people with MS. Judgment and reasoning may also be affected
- Visual disturbances: blurring of vision, double vision (diplopia), optic neuritis, involuntary rapid eye movement, (rarely) total loss of sight
- Balance and coordination problems: loss of balance, tremor, unstable walking (ataxia), dizziness (vertigo), clumsiness of a limb, lack of coordination
- Weakness: usually in the legs
- Spasticity: altered muscle tone can produce spasms or muscle stiffness, which can affect mobility and walking
- Altered sensation: tingling, numbness (paresthesia), a burning feeling in an area of the body or other indefinable sensations
- Abnormal speech: slowing of speech, slurring of words, and changes in rhythm of speech
- Difficulty in swallowing (dysphagia)
- Bladder and bowel problems: the need to pass urine frequently and/or urgently, incomplete emptying or emptying at inappropriate times, constipation, and loss of bowel control
- Sexuality and intimacy: impotence, diminished arousal and loss of sensation
- Pain: facial pain and muscle pains
- Sensitivity to heat: this often causes symptoms to get worse temporarily Though these are a few of the symptoms commonly associated with MS, not all people with MS will experience all of them. Most will experience more than one symptom, however. There is no typical case of MS. Each is unique. oday, life expectancy for those with MS is close to normal.
Most people with MS begin experiencing symptoms between the ages of 20 and
40. But initial symptoms may be vague, may come and go with no pattern or be
attributed to other factors or conditions. For instance, a woman who
experiences sudden bouts of vertigo once every few months may explain away
the symptom by linking it to her menstrual cycle. Or, perhaps, someone who
suddenly has a bit of blurry vision may blame too many hours at the office.
DIAGNOSIS
Diagnosing MS involves several tests and a lot of discussions with several
types of health care professionals. You can expect a complete physical
examination, a discussion of your medical history and a review of your past
and/or current symptoms.
You should pay attention to any symptom suggestive of MS. Early diagnosis of
MS is important because a new generation of treatments introduced in the
1990s can reduce the frequency and severity of MS attacks. In fact, new
research has prompted health care professionals to change the diagnostic
criteria in order to treat more cases of MS as early as possible.
In the past a diagnosis of MS required that the patient experience two
separate "attacks" - symptoms suggestive of neurological damage, such as
blurry vision, numbness, tremors or difficulty with balance. The two attacks
had to be different in type and separated in time, suggesting damage to two
different areas of the central nervous system. The delay between a first and
second attack meant that a conclusive diagnosis could take years.
Today, health care professionals use magnetic resonance imaging (MRI),
introduced in the late 1980s, to scan the brain for lesions indicating early
evidence of damage. An MRI is painless and non-invasive. If you need one, a
health care professional will have you lie on a specialized table, on your
back. The table will be pushed into a tube-like structure and detailed
pictures of your brain and, sometimes, spinal cord will be taken. These
images are able to show scarred areas of the brain.
Despite these results, some neurologists have continued to favor the old
standard of two different kinds of attacks separated in time. The
controversy led to the convening of an international panel of experts, whose
recommendations were published in the April 2, 2001, issue of the Annals of
Neurology. The recommended criteria allow for diagnosis of MS based on one
clinical attack and evidence of lesions on an MRI performed at least three
months after the attack. The MRI must show this specific type of abnormality
to allow for the diagnosis. Yet the "old" standard still remains in force in
some clinics.
Bear in mind that a normal MRI does not ensure that a person does not have
MS. About five percent of MS patients have normal MRIs, according to the
National Multiple Sclerosis Society. Other diagnostic tests may be
recommended to establish an MS diagnosis. These include:
- Visual evoked potential tests, which measure the conduction of visual messages from the eye to the brain. These tests offer evidence of neurological scarring outside the brain. Evoked potential tests are painless and noninvasive. A health care professional or technician will place small electrodes on your head to monitor your brain waves and your response to auditory, visual and/or sensory stimuli. The time it takes for your brain to receive and interpret messages is a clue to your condition.
- A spinal tap, which tests cerebrospinal fluid (fluid surrounding the brain and spinal cord) for substances that indicate strong immune activity in the central nervous system. If you have this test performed, you will likely be given an injection of local anesthesia. You may experience a headache and nausea following the test.
- Blood tests, to rule out other potential causes of symptoms, such as Lyme disease and AIDS.
If you are diagnosed with MS, it will almost certainly be one of four types:
Relapsing-remitting MS: This is the most common form of MS. It is
characterized by periods of exacerbation when the disease is highly active.
During these exacerbations, or attacks, new symptoms may appear and previous
ones may worsen. The attacks are followed by periods of remission, when
disease activity subsides and may be unnoticeable. A remission may last for
months or even years. About 80 percent of MS cases begin as relapsing-remitting.
Secondary progressive MS: According to the National Multiple Sclerosis
Society, more than half of individuals with relapsing-remitting MS will
begin to experience a gradual worsening of symptoms with or without
occasional flare-ups, minor remissions or plateaus within 10 years of
initial diagnosis. This form of MS is called secondary progressive MS.
Current statistics show that 50 percent of relapsing-remitting cases become
secondary progressive within 10 years, and 90 percent become secondary
progressive within 25 years. However, those figures may shrink substantially
thanks to the introduction of the "ABC" disease-modifying drugs (see
Treatment section).
Primary progressive MS: This type of MS is characterized from the onset by a
nearly continuous worsening of the disease, with no distinct relapses or
remissions. There may be temporary plateaus with minor relief from symptoms,
but no long-lasting relief.
About 10 percent of people with MS have primary progressive MS.
Progressive-relapsing MS: This form of the disease is quite rare and takes a
progressive course from the onset, but also is characterized by obvious
acute attacks, with or without recovery. In contrast to relapsing-remitting
MS, the periods between relapses are characterized by continuing disease
progression. About 10 percent of people with MS have progressive-relapsing MS.
MS varies so greatly in each individual, it is hard to predict the course
the disease might take. However, some studies show that people who have few
attacks in the first five years following a positive diagnosis of MS, long
intervals between attacks, complete recoveries and attacks that are sensory
only in nature generally have a less debilitating form of the disease.
On the other hand, people who have early symptoms that include tremors, lack
of coordination or frequent attacks with incomplete recoveries generally
have a more progressive form of MS. These early symptoms indicate that more
myelin (the fatty insulation surrounding nerve cells in the brain and spinal
cord) has been damaged.
Since MS generally strikes a woman during childbearing years, many women
with the disease wonder if they should have a baby. Studies show that MS has
no adverse effects on the course of pregnancy, labor or delivery; in fact,
symptoms often stabilize during pregnancy. Although MS poses no significant
risks to a fetus, physical limitations of the mother may make caring for a
child more difficult. Also, women with MS who are considering having a child
need to know that certain drugs used to treat MS can cause birth defects and
can be passed to a fetus through blood and to an infant through breast milk.
You should discuss which drugs to avoid during pregnancy and while
breastfeeding with your health care professional.
Reprinted with Permission
