Multiple Sclerosis
Symptoms
These tend to occur in attacks usually lasting several weeks and at least
in the first few attacks, remissions that may be total or partial. Symptoms
that are more short-lived lasting minutes are only very rarely due to MS. Loss
of vision in one eye (optic neuritis), loss of sensation in arms or legs or
loss of strength (myelitis) may occur. Double vision, unsteadiness (brainstem
lesion) are fairly typical sort of attacks. In some patients but by no means
all, a progressive element sets in. In these cases, function of the legs with
weakness and unsteadiness (ataxia) and bladder problems sometimes leading to
being wheelchair bound, can occur. The range is extreme and simple classifications
of MS largely for clinical trial uses has over simplified the situation that
does not account for patients who have a single attack in their lifetime to
the very rare patients who become disabled very quickly or can even die.
Diagnosis
It remains important to have clinical symptoms that conform to inflammation
of the central nervous system such as a myelitis or optic neuritis. Back up
support for the diagnosis and simultaneously exclusion of other possibilities
would normally be achieved from doing an MRI scan of the head, spine or both
and when changes are not characteristic, some Neurologists will also advise
a lumbar puncture to look specifically for changes in the immuno-globulin fraction
known as oligoclonal bands. In patients with MS, it is possible for either the
MRI scan or the lumbar puncture to not show a positive result but almost impossible
for both to be negative. The investigations do not give any indication as to
prognosis.
Characteristically the MRI scan will show “white dots” within the white matter
and if the spinal scan shows anything which it often does not, it will again
show “white blobs” characteristic of inflammation. Other tests of an electrical
sort known as visual evoked and auditory evoked potentials occasionally get
done but have really been superseded by MRI and oligoclonal banding.
Cause
The cause is unknown but the effect is to strip the sheath off the central
nervous system neurones that makes them function poorly and slowly. There is
also inflammation. In some cases the nerve cells will eventually die. In patients
who improve, remyelination must occur but it is always imperfect but fortunately
can be enough to allow the symptoms to remit. Like many complex conditions,
MS does not run in families in the strict sense of the term though there is
a slight increased incidence suggesting that there are pre-disposing genetic
factors. However, it seems unlikely that genetics factors on their own can cause
the condition and the presumption has always been that there is interaction
with a virus through an immunological achilles heel that gives rise to persistent
inflammation. Perhaps the immune system in trying to continually rid the body
of the virus also attacks the myelinia hypothesis known as molecular mimicry.
MS is much less common in countries close to the equator and this is explained
on environmental, not genetic grounds as if individuals migrate before late
teenage years to the Northern hemispheres, they acquire the increased chances
of getting MS.
Treatment
Not all patients require treatment as they may improve under their own steam.
In severe or persistent attacks, a short course of steroids are normally advised.
These do not always work and when they do, promptly speed up recovery rather
than cause a recovery in patients who would not otherwise have improved in time.
New drugs are becoming available. Beta Interferon is on the market though not
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