Multiple Sclerosis: Facts and Figures at a Glance
What is Multiple Sclerosis?
- Multiple sclerosis (MS) is a demyelinating disease of the central nervous
system attacking the brain and spinal cord. The cause of MS is unknown. Some
as yet unidentified agent, enhanced by genetic and environmental factors,
triggers a cascade of immunological etkinligini which ultimately results in the
destruction of the fatty myelin sheath surrounding nerves and later the nerve
axons themselves. Multiple plaques of scar tissue are formed where myelin
has been attacked. This damage means nerves are unable to conduct impulses
and the results can mean poor muscular co-ordination, impaired vision, speech
and cognitive function, and poor bladder and bowel control depending on the
areas of the brain or spinal cord predominantly affected.
Epidemiology
- Estimates of the number of people affected by MS throughout the world vary
between 1.11 and 2.5 million.1, 2 In western Europe, the number
is estimated at 350,000, and in the US, 250,000. The UK figure is estimated
at 85,000.
- MS is one of the 100 disorders causing the greatest burden of disease worldwide.2
- MS is predominantly a disease of temperate climates. It is distributed throughout
the world in three zones of high, medium and low frequency.3 In
the high frequency zone – Europe, Canada, the former USSR, Israel, Northern
USA, New Zealand and SE Australia – prevalence rates are greater than 30 (mostly
between 50 and 120) per 100,000. In the lowest frequency zone – Asia, Africa
and South America – prevalence is less than 5 per 100,000.
- The risk of developing MS in a high frequency zone is around 1 per 1,000.
Demographics
- MS affects women more than men in the ratio of about 2:1, possibly due to
the influence of female sex hormones on the immune response.
- Caucasians of European descent are affected much more frequently than other
races, suggesting a genetic element.
- The disease usually first affects people when they are young (aged between
20 and 40), typically manifesting itself around the age of 30.
Diagnosis and assessment
- MS is diagnosed on the basis of the patient's history of symptoms, a detailed
neurological examination, magnetic resonance imaging (MRI) and cerebrospinal
fluid (CSF) analysis.
- According to the clinical pattern of relapses and residual disability experienced,
patients are classified as having one of four patterns of MS.
- Benign
- Relapsing-remitting
- Secondary progressive
- Primary progressive
Benign MS
Patients stay relatively unimpaired for many years after an initial attack.
Approximately 20 per cent of patients have this form of disease.
Relapsing-remitting MS
This is the usual pattern of disease in the first 20 years experienced by
around 85 per cent of patients. They experience periodic attacks associated
with some degree of impairment which subsequently resolves to a large degree
if not completely. Around 25–35 per cent of patients have this pattern at
any one time. More than 50% of patients progress from relapsing-remitting
MS to the secondary progressive form.2
Secondary progressive MS
This form of the disease represents a continuum with relapsing–remitting
MS and is marked by fewer remissions occurring after attacks and accumulating
disability between relapses. An estimated 40 per cent of MS patients are in
this category.
Primary progressive MS
This is characterised by a gradual, insidious and progressive deterioration
with disability developing from the onset of disease without remissions. About
10 per cent or fewer MS patients have this condition.
Assessing disability
- The extent of a patient's neurological disability and deterioration is assessed,
usually for clinical trial purposes, on the Kurtzke expanded disability scale
(EDSS).4 This ranges from 0 (normal) to 10 (death) with the steps
in between representing an increasing loss of neurological function. A score
of 3 reflects moderate disability, 7 indicates a patient is wheelchair bound,
and a score of 8, means bed bound.
Treatment
- Treatments for MS fall into three categories.
- Acute
- Symptomatic
- Disease-modifying
Acute
Drugs used to treat acute exacerbations or relapses are usually the corticosteroids
such as methylprednisolone. They reduce inflammation and shorten the time
to recovery after a relapse. They do not affect the course of MS and in any
case could not be taken long term because of their well-known side effects.
Symptomatic
Drugs used to control symptoms experienced by MS patients include those to
ease pain, spasticity, depression, fatigue and urinary problems. Other non-drug
treatments such as physiotherapy are helpful in teaching patients to circumvent
the problems caused by MS.
Disease-modifying
The only drugs demonstrated to alter the natural course of MS include interferon
beta-1b (Betaferon®), interferon beta-1a and glatiramer acetate. Of these,
only Betaferon® is licensed for the treatment of both relapsing-remitting
and secondary progressive MS.
Interferons are cytokines with the capacity to modulate the etkinligini of the
human immune system. For example, Betaferon prevents activated T-lymphocytes
penetrating the blood brain barrier and intercepts to inhibit their destructive
cascade of etkinligini.
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REFERENCES
1. Goodkin DE. Commentary. Lancet 1998; 352: 1486–1487.
2. Rudick RA, Cohen JA, Weinstock-Guttman B, et al. Management of Multiple
Sclerosis. New Eng J of Med 1997; 337: 1604-1611.
3. Kurtzke JF. Epidemiology of MS including special reference to developing
countries. Euro J Neurol 1998; 5 (suppl 2): S5–6
4. Kurtzke JF. Rating neurologic impairment in multiple sclerosis: an expanded
disability status scale (EDSS). Neurol 1983; 33: 1444–52.
Betaferon® is a registered trademark of Schering AG, Berlin