Download Multiple Sclerosis explained

Multiple Sclerosis explained
Multiple sclerosis (MS) is a neurological disorder that is typically
characterized by symptoms that grow progressively more severe with
time. Some patients may experience only one or a few attacks of
symptoms. Others will have life-changing symptoms as they cope
with increasing debilitation and paralysis.
The National Multiple Sclerosis Society estimates 3.5 million people
worldwide have the disease.
MS is believed to be an autoimmune disorder, in which the body’s
immune system attacks the myelin that surrounds nerves in the brain
and spinal cord. Normally the myelin helps conduct signals along the
length of the neurons (nerve cells). In patients with MS, the myelin
degrades and is replaced with scar tissue, a process termed sclerosis.
The loss of myelin causes the nerve signals to move more slowly or
become distorted or blocked.
Scientists do not completely understand why the immune system
begins to attack the body’s nerves. There is some evidence of a
genetic link that may make some people more susceptible to an
unknown environmental trigger. Many researchers believe the trigger
is a virus or bacteria, but other factors are also suspected.
There are four types of MS that are generally recognized. They differ
in how the symptoms progress. Relapsing-remitting MS patients
experience attacks of symptoms that may last weeks or months
before a period of remission. After several years, it may develop into
secondary-progressive MS with constant symptoms that become more
severe and lack significant periods of remission. Primary-progressive MS
is similar to secondary-progressive MS, but is not preceded by a
period of relapse and remission. Patients with progressive-relapsing MS
experience symptoms that continually get worse, as well as periodic
attacks of more severe symptoms.
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A physician may suspect that a patient has MS based on the patient’s
symptoms and the results of a neurological examination. To confirm
the diagnosis, a combination of tests is required. These are likely to
include imaging tests (e.g., MRI), an analysis of cerebrospinal fluid
(spinal tap) and an evoked potential study.
There is a great deal of ongoing research concerning MS. Much of it
is focused on trying to discover the causes of the disease. It is hoped
that finding the cause will lead to ways to prevent and cure the
disabling disease.
Multiple sclerosis (MS) is a non-contagious, neurological disorder
that may cause symptoms that range from mild to severe and can
change a patient’s life. As the disease progresses, most patients
maintain their ability to walk, though many require the assistance of a
cane or similar device. A third of MS patients may be eventually
paralyzed by the disease. The disease also causes increasing levels of
fatigue and some people experience vision loss. The average life span
of patients with MS is slightly shorter than the rest of the population,
but does not differ significantly.
The average age of diagnosis of MS is roughly age 30. Symptoms may
first appear at any point throughout a person’s life, although they
usually start between the ages of 20 and 50.
It is a disease that is twice more likely to develop in women than men
and is more common in Caucasian people than other races.
The symptoms of MS result from the loss of myelin from neurons
(nerve cells) in the brain and spinal cord, although scientists are
unsure why this occurs. Myelin is a fatty material that forms a layer
around the neurons of the central nervous system. It is believed to
help conduct the electrical nerve signal from one end of the neuron
to the other. MS causes myelin to degrade and it may be replaced by
scar tissue, a process that is called sclerosis. Without myelin, nerve
signals move more slowly and they may be distorted or blocked by
the scar tissue or other damage to the neuron.
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Types and differences of multiple sclerosis
Multiple sclerosis (MS) is a neurological disorder that primarily
affects movement and vision, as well as other senses. There are
several types of the disease that are classified according to the pattern
of progression. While different patients will experience different
patterns of progression, MS is usually classified as one of the
following:
•
Relapsing-remitting MS. Patients experience symptoms during
attacks that may last weeks to months. These periods are
followed by a remission stage when symptoms may partially or
completely fade. Some patients experience only one or two
attacks in their lifetime, but others face worsening relapses with
shorter and less frequent remission stages. It is the most
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common form of MS and is diagnosed in 85 percent of patients
according to the National Multiple Sclerosis Society (NMSS). It
is most often diagnosed in patients between 25 and 29 years of
age.
•
•
Secondary-progressive MS. Half of patients with the relapsingremitting form of MS will develop this form within 10 years of
the initial diagnosis. It is characterized by initial periods of
distinct attacks followed by worsening symptoms that may or
may not fluctuate in intensity. People with secondaryprogressive MS do not usually have remissions, although they
may experience temporary improvements or plateaus in their
condition.
Primary-progressive MS. This form of MS is characterized by a
slow progression of disease with symptoms that continue to
grow more severe. Patients do not usually experience distinct
attacks or periods of remission. According to the NMSS, it is
diagnosed in approximately 10 percent of patients, and usually
only occurs in patients who are in their 40s or older.
• Progressive-relapsing MS this rarest form of MS affects an
estimated 5 percent of patients with the disease according to
NMSS. They experience continuous symptoms that get
progressively worse in conjunction with attacks of more severe
symptoms.
Potential causes of multiple sclerosis
Little is known about what causes multiple sclerosis (MS). Most
scientists believe it is an autoimmune disorder, which is when the
immune system produces a reaction that attacks the body’s own
tissues. In the case of MS, the reaction is directed against the myelin
sheath of nerve cells (neurons). What may be causing this immune
response is not completely understood.
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Many researchers believe MS may result from a combination of
genetic and environmental factors. While there seems to be a slightly
higher rate of incidence when a close family member has the disease,
there is no distinct pattern of inheritance to establish a genetic cause.
Instead, genetics are suspected of making a person more susceptible
to unknown factors that trigger the disease. There are many theories
as to what the trigger for MS may be, including:
•
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Viral or bacterial disease. Some scientists think a virus or bacteria
infection may trigger the body’s immune system to mistakenly
attack the myelin around nerve cells. Antibodies to the EpsteinBarr virus, which causes infectious mononucleosis, have been
found in nearly 100 percent of MS patients (in general, they are
found in up to 90 percent of adults). They are also found more
frequently in children who develop MS than in other children.
Other infectious agents being studied include Chlamydia
pneumoniae (a cause of pneumonia) and the microorganisms that
cause measles and canine distemper.
Environmental pollution. The occurrence of apparent clusters
(disease occurrence at a rate higher than expected) of MS has
resulted in investigations into potential causes of the disease.
Sometimes these clusters have occurred near potential sources
of industrial contamination leading some scientists to speculate
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that environmental pollutants may trigger MS. No definitive
evidence to support this theory has been found.
• Vitamin D deprivation. People who live farther away from the
equator and are exposed to less sunlight are more likely to
develop MS. Because sunlight is needed by the body to make
vitamin D, some scientists believe that reduced levels of the
vitamin may be a cause of the disease.
Signs and symptoms of multiple sclerosis
The signs and symptoms of multiple sclerosis (MS) vary from patient
to patient in severity and frequency. They are likely to include:
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Double vision or vision loss
Numbness, tingling or weakness in one or more limbs
Unsteady walking
Sensitivity to heat
Partial or complete paralysis
Sensation of an electric shock when bending the neck
Lack of coordination
Fatigue
Dizziness
Muscle stiffness or spasticity
Slurred speech
Bladder, bowel or sexual dysfunction
Forgetfulness
Many people with MS also experience depression, which may be
related to the nature of the disease or a consequence of living with a
chronic illness. People with MS may also experience pain or develop
trigeminal neuralgia, ataxia and seizures.
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Depending on the form of MS, the symptoms may come in periodic
attacks followed by remission or may progressively become worse.
Pregnancy and the resulting changes in hormones can affect the
occurrence of MS symptoms. Attacks usually occur less frequently
during the second and third trimester, though they may be more
severe following birth.
Diagnosis methods for multiple sclerosis
Multiple sclerosis (MS) presents various difficulties for diagnosis. MS
may be suspected based on the occurrence of its symptoms, but
some symptoms may also be caused by other diseases. In addition,
the symptoms of MS are often temporary and may fade before
patients are examined. If this occurs, it is recommended that patients
relate their medical history, including what symptoms have been
experienced, as well as the frequency, severity and timing of
symptoms.
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The physician is likely to perform a neurological examination. This
may indicate signs or symptoms of which the patient was unaware,
such as lack of coordination. The examination will test the patient’s
reflexes, muscle strength and tone, sense of touch, vision, gait,
posture, coordination, balance and mental skills.
A number of techniques are available to help confirm suspected MS
based on the patient’s medical history and the results of the
neurological exam. These include:
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MRI (magnetic resonance imaging). This technique uses magnetic
fields and radio waves to allow physicians to see MS-related
damage in the brain and spinal cord. The procedure takes about
an hour and provides more detailed images than CAT scans
(computed axial tomography) and other imaging techniques.
Spinal tap. Cerebrospinal fluids from the spinal column may be
extracted using a needle and analyzed for indicators of MS.
These may include abnormal levels of white blood cells,
proteins and glucose (blood sugar) in the spinal fluid. The
process takes about 45 minutes.
Evoked potential study. These tests measure the electrical signals
that travel from the sensory organs to the brain and may be
used to detect abnormal functioning of the central nervous
system. During the test, electrodes are attached to the scalp to
measure the patterns of brain activity that occur following
stimulation of the senses. The results are compared to normal
patterns. Slow or abnormal brain activity may be an indication
of MS. The tests usually take about 45 minutes.
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•
Nerve conduction velocity. A measure of the electrical activity of
nerves. Electrodes on the surface of the skin send and detect
electricity as it moves through the nerves. Slower than normal
results may be indicative of nerve damage. To prepare for this
test, it may be recommended that patients avoid caffeine and
smoking for three hours, and anti-inflammatory medications
for 24 hours.
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A definitive diagnosis of MS relies on evidence of changes in multiple
parts of the central nervous system. These changes must include the
degradation of myelin into scar tissue as well as at least two separate
attacks of symptoms.
Treatment and prevention of multiple sclerosis
To date, there is no method to cure or prevent multiple sclerosis
(MS). Years of research have allowed physicians to develop several
forms of treatment for the disease. Medications have been developed
that help various aspects of MS. These include:
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Treating symptoms, such as muscle relaxants to relieve muscle
spasms.
Altering the progression of the disease, including reducing the
frequency, length and severity of attacks.
Medications are most effective when used in the early stages of the
disease.
In addition to medications, other forms of treatment for both the
physical and psychological impact of MS include physical therapy,
individual counseling and support groups.
Ongoing research regarding multiple sclerosis
Multiple sclerosis (MS) is a common neurological disorder and is the
subject of continuing medical research. Scientists involved in the
research are investigating many aspects of the disease, including its
causes and potential prevention methods.
Research into the causes of MS is multifaceted. Studies are underway
to investigate possible genetic factors that may be involved in the
disease and how genetic engineering may be able to prevent MS.
Scientists also are examining how viruses, bacteria and pollution may
trigger MS. If these triggers can be identified, then there may also be
ways to address them. Additionally, stem cell research is in
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development for MS. It is currently focused on repairing the damage
inflicted on body tissue by MS rather than on preventing the disease.
Another topic of research interest is the blood brain barrier. The
membrane around the brain typically serves to control the passage of
nutrients and waste products between the central nervous system and
the blood. If this barrier malfunctions, it may allow the passage of
chemicals into the brain that may be involved in MS.
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