Multiple Sclerosis or MS is a disease of the central nervous system characterised by inflammation and demyelination, the gradual loss of the insulation material around the nerves known as myelin. Sclerosis is the term given to describe the thickened and scarred small lesions which occur in the nerve tracts. The disease is continually active and forms new lesions regularly leading to gradually increasing levels of disability. The most common form of MS is the relapsing and remitting kind, meaning there are periods of worsening followed by at least partial recoveries.

MRI scanning has allowed an important increase in the ability to confirm MS as a diagnosis as the lesions in the central nervous system show up in the scans. No triggering factor or agent for this disease has yet been found, although it is known to be better during pregnancy and worse in the period following birth of the child. MS may be brought on by a number of different factors but only a quarter of MS onsets can be linked to any kind of infection at the time.

There are several different forms of multiple sclerosis which have differing patterns and severities of disease. MS is more common in Caucasian populations and the incidence increases with increasing latitude, in other words how far to the north the individual lives. Genetic inheritance may be important in the risk of getting MS but the environment plays a role somewhere as it is known that moving to a higher risk area before the age of 15 years means you suffer the increased risk of the new area.

2.5 multiple sclerosis sufferers are estimated to be presently living in the world and due to the typical age being a younger group this is the cause of important levels of disability and disturbance of family and economic life. Death is not a direct consequence of multiple sclerosis but there is an estimated reduction in life years of between five and seven, possibly due to the consequences of immobility such as urinary infections. Northern Europe shows the highest incidence of this disease and women present from 1.6 to 2.1 times more often than men in general, although in younger (under fifteen) and older (over fifty) women the proportion is three to one.

Male patients are more likely to get the primary progressive form of the disease while females are more likely to get the relapsing form. Attacks of the disease manifest themselves in newly developed central nervous system symptoms, symptoms which vary in part of the body affected and are spread over a variable time. Typical examples can be a sudden weakness of one or more of the limbs, double vision from involvement of the optic nerve and loss of sensations in variable areas. There can also be a steady worsening in both the physical and mental abilities without obvious attacks.

The relapsing and remitting type of multiple sclerosis exhibits acute attacks with an improvement again afterwards, however most sufferers in this very common group will eventually become more steadily worse which is termed secondary progressive disease. If affected by the primary progressive type the patient typically undergoes a steady worsening in ability without remissions, with deterioration to complete paralysis. This type of disease responds less well to usual treatments and is more disabling. Relapsing and progressive disease occurs when the disability from attacks is not recovered in remissions.

While MS symptoms often spread themselves over a variety of functions in any particular person they can be focussed on more specific areas such as mostly affecting balance, vision or mental abilities. At some point in the course of the disease sufferers seem to reach a threshold where they worsen in a neurodegenerative pattern rather than secondary to inflammation. The complex nature of multiple sclerosis means that virtually any neurological system can be affected in minor ways, or the damage can be concentrated in one particular part of the system. Even without much evidence of nervous system lesions people can lose significant mental ability.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and Physiotherapists in Manchester. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.