About Multiple
Sclerosis
Multiple Sclerosis is a chronic disease that affects the
brain and spinal cord. multiple sclerosis can cause a variety
of symptoms, including changes in sensation, visual problems,
weakness, depression, and difficulties with coordination and
speech.
Although many patients lead full and rewarding lives, multiple
sclerosis can cause impaired mobility and disability in the
more severe cases.
Multiple Sclerosis attacks the brain and spinal cord, which
contain nerves that carry information and allow the brain to
control the body. Surrounding and protecting these nerves is a
layer of fat, called myelin, which helps nerves carry
electrical signals. Multiple Sclerosis causes gradual
destruction of myelin (demyelination) in patches throughout the
brain and/or spinal
cord, causing different symptoms depending upon which
signals are interrupted.
Multiple Sclerosis results from attacks by an individual's
immune system on his or her own nervous system, and it is
therefore categorized as an autoimmune disease. The name
multiple sclerosis refers to the multiple scars (or scleroses)
on the myelin sheaths.
Signs and Symptoms
Individuals with multiple sclerosis may experience a wide
variety of symptoms. The initial attacks are often transient,
mild (or asymptomatic), and self-limited. They often do not
prompt a health care visit and sometimes are only identified in
retrospect once the diagnosis has been made based on further
attacks.
The most common initial symptoms reported are: changes in
sensation in the arms, legs or face (33%), complete or partial
vision loss (optic neuritis) (16%), weakness (13%), double
vision (7%), unsteadiness when walking (5%),
and balance problems (3%).
Clinical Entities
Three clinical entities warrant further discussion because
affected individuals are often eventually diagnosed with
multiple sclerosis. (However, multiple sclerosis is only one of
several potential causes for these entities.)
Optic Neuritis
Individuals typically experience rapid onset of pain in one
eye, followed by blurry vision in part or all of the visual
field of that eye. This is a result of involvement of the optic
nerve by multiple sclerosis.
At least 15% and as many as 75% of individuals who have an
episode of optic neuritis go on to develop multiple sclerosis.
The blurred vision usually resolves within six months, but
individuals are often left with less vivid color vision
(especially red) in the affected eye.
Internuclear Ophthalmoplegia
Individuals usually notice double vision (diplopia),
especially when looking to one side. This is the result of
failure of the lateral rectus muscle to contract appropriately,
so that the eyes do not move equally (called disconjugate
gaze). Internuclear ophthalmoplegia occurs when multiple
sclerosis affects a part of the brain stem
called the medial longitudinal fasciculus, which is responsible
for communication between the two eyes.
Transverse Myelitis
Individuals typically develop rapid onset of numbness,
weakness, bowel or bladder dysfunction, and/or loss of muscle
function, typically in the lower half of the body. This is the
result of multiple sclerosis attacking the spinal cord.
As many as 80% of individuals with transverse myelitis are left
with lasting disabilities, even though there is usually some
improvement during the first two years.
Diagnosis
Multiple Sclerosis is difficult to diagnose in its early
stages. In fact, definite diagnosis of multiple sclerosis
cannot be made until there is evidence of at least two
anatomically separate demyelinating events occurring at least
thirty days apart. The McDonald criteria represent
international efforts to standardize the diagnosis of ms using
clinical data, laboratory data, and radiologic data.
Clinical data alone may be sufficient for a diagnosis of
multiple sclerosis. If an individual has suffered two separate
episodes of neurologic symptoms characteristic of multiple
sclerosis, and the individual also has consistent abnormalities
on physical examination, a diagnosis of multiple sclerosis can
be made with no further testing. Since some people with
multiple sclerosis seek medical attention after only one
attack, other testing may hasten the diagnosis and allow
earlier initiation of therapy.
Course
The course of multiple sclerosis is difficult to predict,
and the disease may at times either lie dormant or progress
steadily. Several subtypes, or patterns of progression, have
been described. Subtypes use the past course of the disease in
an attempt to predict the future course. A person diagnosed
with a particular subtype may, for unclear reasons, switch from
one subtype to another over time.
Factors triggering a relapse
Multiple Sclerosis relapses are often unpredictable and can
occur without warning with no obvious inciting factors.
Some attacks, however, are preceded by common triggers. In
general, relapses occur more frequently during spring and
summer than during autumn and winter. Infections, such as the
common cold, influenza, and gastroenteritis, increase the risk
for a relapse. Emotional and physical stress may also trigger
an attack, as can severe illness of any kind.
Pathophysiology
Although much is known about how multiple sclerosis causes
damage, the reasons why multiple sclerosis occurs are not
known.
Complications
Multiple Sclerosis is a disease in which the body's immune
system attacks the myelin surrounding nerve cells. Myelin is a
fatty substance which covers the axons of nerve cells and is
important for proper nerve conduction.
A special subset of white blood cells, called T cells, plays
a key role in the development of multiple sclerosis. Under
normal circumstances, these lymphocytes can distinguish between
self and non-self. However, in a person with multiple
sclerosis, these cells recognize healthy parts of the central
nervous system as foreign and attack them as if they were an
invading virus.
Why Multiple Sclerosis Occurs
Although many risk factors for multiple sclerosis have been
identified, no definitive cause has been found. Multiple
sclerosis likely occurs as a result of some combination of both
environmental and genetic factors. Various theories try to
combine the known data into plausible explanations. Although
most accept an autoimmune explanation, several theories suggest
that multiple sclerosis is an appropriate immune response to an
underlying condition.
Treatment
There is no known definitive cure for multiple sclerosis.
However, several types of therapy have proven to be helpful.
Different therapies are used for patients experiencing acute
attacks, for patients who have the relapsing-remitting subtype,
for patients who have the progressive subtypes, for patients
without a diagnosis of ms who have a demyelinating event, and
for managing the various consequences of multiple sclerosis
attacks. Treatment is aimed at returning function after an
attack, preventing new attacks, and preventing disability.
Management of Acute Attacks
During symptomatic attacks, patients are often hospitalized.
They are typically given high doses of corticosteroids such as
methylprednisolone intravenously for several days to increase
the chances that the attack will end sooner and leave fewer
lasting deficits. There is some support for using oral
corticosteroid pills during an attack, but clinical practice
varies. However, there is no data to support the continued use
of steroids for preventing ms after an initial attack.
Management Of Progressive Multiple Sclerosis
Treatment of progressive multiple sclerosis is more
difficult than relapsing-remitting multiple sclerosis, and many
patients do not respond to any therapy.
A wide range of medications have been used to try to slow
the progression of disease. Many therapies have been shown to
have some effect on disease progression and resulting
disability, but most therapies have significant side effects
which limit their long-term use. Therefore they are often
appropriate only for the most rapidly progressive cases.
Management Of Demyelination Without A Diagnosis Of Multiple
Sclerosis
Several studies have shown that starting treatment with
interferon (Avonex or Rebif) during the initial attack (and
prior to the second attack required for a definite diagnosis of
multiple sclerosis) can decrease the chance that a patient will
develop multiple sclerosis.
A separate medication, intravenous immunoglobulin (IVIG) has
also shown promise in reducing progression to multiple
sclerosis in this set of patients. Therefore, in certain
patients, it is important that therapy be started prior to
definite diagnosis.
Management Of The Effects Of Multiple Sclerosis
Because much of the damage caused by multiple sclerosis is
irreversible, management of the resulting deficits is very
important. As for any patient with neurologic deficits, a
multidisciplinary approach is key to limiting and overcoming
disability. Physical therapy, occupational therapy, and speech
therapy are all important components of a comprehensive
approach to maintaining quality of life.
Therapies Under Investigation
A family of cholesterol-lowering drugs, the statins, have
shown anti-inflammatory effects in animal models of multiple
sclerosis. However, as of 2005 there is not sufficient evidence
that statins are beneficial in the treatment of human ms
patients with normal cholesterol levels.
A recent study found that women who took vitamin D
supplements were 40% less likely to develop multiple sclerosis
than women who did not take supplements. However, this study
does not provide enough data to conclude that vitamin D has a
beneficial influence on ongoing ms. Furthermore, it could not
distinguish between a beneficial effect of vitamin D and that
of multivitamin supplements including vitamin E and various B
vitamins, which may also exert a protective effect.
Side Effects Of Medications For Relapsing-Remitting Multiple
Sclerosis
The two most common types of medications used to treat
relapsing-remitting multiple sclerosis have significant side
effects which warrant further discussion. Both the interferons
and glatiramer acetate are available only in injectable forms,
and both can cause irritation at the injection site.
Interferons are produced in the body during illnesses such
as influenza in order to help fight the infection. They are
responsible for the fever, muscle aches, fatigue,
and headache common during influenza infections.
Prognosis
The future course of the disease (or prognosis) for people
with multiple sclerosis depends on the subtype of the disease,
the individual's sex and race, their age, their initial
symptoms, and the degree of disability they experience. The
life expectancy of people with multiple sclerosis is now nearly
the same as that of unaffected people. This is mainly due to
improved methods of limiting disability, such as physical
therapy and speech therapy, and more successful treatment of
common complications of disability,such as pneumonia and
urinary tract infections.
Risk Factors
In northern Europe, continental North America, and
Australasia, about one of every 1000 citizens suffers from
multiple sclerosis, whereas in the Arabian peninsula, Asia, and
continental South America, the frequency is much lower. In
sub-Saharan Africa, multiple sclerosis is extremely rare.
With important exceptions, there is a North-South gradient
in the Northern hemisphere and a South-North gradient in the
Southern hemisphere, with multiple sclerosis being much less
common in people living near the equator.
Climate, diet, geomagnetism, toxins, sunlight exposure,
genetic factors, and infectious diseases have all been
discussed as possible reasons for these regional differences.
Environmental factors during childhood may play an important
role in the development of multiple sclerosis later in
life.
This idea is based on several studies of migrants showing
that if migration occurs before the age of fifteen, the migrant
acquires the new region's susceptibility to ms. If migration
takes place after age fifteen, the migrant keeps the
susceptibility of his home country. Additionally, smoking has
been shown to be an independent risk factor for developing
multiple sclerosis.
History
A French neurologist named Jean-Martin Charcot (1825–93) was
the first person to recognize multiple sclerosis as a distinct,
separate disease in 1868.
Summarizing previous reports and adding his own important
clinical and pathological observations, Charcot called the
disease sclerose en plaques.
The three signs of multiple sclerosis now known as Charcot's
triad are dysarthria (problems with speech), ataxia (problems
with coordination), and tremor.
Prior to Charcot, Robert Hooper (1773–1835), a British
pathologist and practicing physician, Robert Carswell
(1793–1857), a British professor of pathology, and Jean
Cruveilhier (1791–1873), a French professor of pathologic
anatomy, had described and illustrated many of the disease's
clinical details.
Natural Remedies
Although some doctors recommend fish oil capsules for people
with multiple sclerosis, few investigations have explored the
effects of this supplement.
In one small trial, people with multiple sclerosis were
given approximately 20 grams of fish oil in capsules per day.
After one to four months, 42% of these people received slight
but significant benefits, including reduced urinary
incontinence and improved eyesight.
However, a longer double-blind trial involving over 300
people with multiple sclerosis found that half this amount of
fish oil given per day did not help.
A preliminary, two-year intervention trial tested the
effects of fish oil supplements (5 ml of fish oil per day,
providing 400 mg of EPA and 500 mg of DHA) combined with other
dietary supplements and dietary changes in people with newly
diagnosed, relapsing-remitting multiple sclerosis.
References For Multiple Sclerosis
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McDonald WI; Compston A; Edan G; Goodkin D;
Hartung HP; Lublin FD; McFarland HF; Paty DW; Polman CH;
Reingold SC; Sandberg-Wollheim M; Sibley W; Thompson A;
van den Noort S; Weinshenker BY; Wolinsky JS. Recommended
diagnostic criteria for ms: guidelines from the
International Panel on the diagnosis of multiple
sclerosis. Ann Neurol 2001 Jul;50(1):121-7
Rudick, RA, Whitaker, JN. Cerebrospinal fluid
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Princeton, NJ 1987
Gronseth GS; Ashman EJ. Practice parameter: the
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