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What is MS?

MS is the most common disease of the central nervous system affecting young adults. The central nervous system comprises the brain and spinal cord. Together with the nerves connecting to the rest of the body, they form the body's communication network.

Nerve cells (neurons) contain nerve fibres (axons), which are surrounded by a protective sheath of fatty protein called myelin. This protects the nerves in the same way that insulating material protects an electric wire. In MS, damage or scarring occurs to the myelin sheath. This damage (called demyelination) disrupts the way in which messages, or nerve impulses, are carried to and from the brain and so can interfere with a range of the body's functions.

A nerve cell or neuron

The term 'multiple sclerosis' comes from 'sclerosis', which means 'scarring' and 'multiple', which relates to the sites of the scarring, which can occur in different places throughout the brain and spinal cord.

The symptoms experienced depend on the position and extent of the scarring or lesions within the central nervous system and on how much damage has occurred, so no two people with MS will have exactly the same set of symptoms.

In the earlier stages of MS, the central nervous system can often repair areas of damaged myelin or reroute messages via different pathways of neurons thereby avoiding the damaged areas. This explains why episodes of symptoms (relapses) can be followed by weeks, months or even years when symptoms improve or disappear (remission). However, if the area of damage becomes too large, communication with that specific part of the central nervous system may become permanently blocked.

What are the common symptoms at the time of diagnosis?

  • fatigue
  • loss of vision in one eye
  • blurred or double vision
  • dragging a foot
  • weakness of limbs
  • reduced coordination
  • balance problems
  • numbness, pins and needles, burning sensations

What causes MS?

The cause of MS is not yet fully understood but is thought to be a combination of environmental and genetic factors. One theory is that some people have certain groups of genes that make them more likely to develop MS. It may be that an external factor, such as a virus, triggers a reaction in those with this genetic predisposition causing the immune system to malfunction and attack its own myelin.

More on the cause of MS