Multiple sclerosis
Definitions
Multiple sclerosis (MS) is defined as a chronic, inflammatory, demyelinating auto-immunological disease. The name multiple sclerosis refers to the scars (sclerosis), known as plaques, formed in the nervous system. There are four types of MS classified according to the course/progression of the disease process.
Benign MS
This subgroup is diagnosed retrospectively. These individuals show little or no disease progression.
Relapsing remitting MS
This is the most common type of MS representing 80% of the people diagnosed with MS. Symptoms occur for a period of time (relapse, exacerbation) and then improve (remission), either partially or completely.
Secondary progressive MS
This type is a progression of relapsing remitting MS, when the individual shows a sustained deterioration for at least 6 months. On average, by 15 years, around two-thirds of people with relapsing remitting MS will have developed secondary progressive MS.
Epidemiology
Prevalence
According to government guidelines, MS is diagnosed in 3.5–6.6 people per 100 000 of the population each year in England and Wales.
Aetiology
The definitive cause is unknown. However, the evidence suggests that the cause may be a combination of both genetic and environmental factors.
Environmental factors
Viral infection
The evidence indicates that a viral infection, produced by a widespread microbe rather than a rare pathogen, could be the origin of the disease. For example, human herpes virus, chicken pox and glandular fever.
Vitamin D deficiency
Vitamin D deficiency has been linked with a higher risk of MS. This may occur as a result of inadequate intake of the vitamin, coupled with a lack of exposure to sunlight and may explain the geographical distribution of MS in countries further away from the equator.
Full access? Get Clinical Tree
