Multiple Sclerosis (MS)

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS)

• Messages from our brain and spinal cord to the rest of body is disrupted or damaged. Messages are carried by nerve fibres.
• The basic functional unit of nervous tissue is the neuron.
  • A neuron is made up of a nerve cell body plus small branches called fibres. One type of fibre, the dendrite, carries nerve impulses to the nerve cell body.
  • A single fibre, the axon, carries impulses away from the nerve cell body.
  • Some axons are covered with a fatty material called myelin that insulates and protects the fibre.
  • Myelinated axons are called white fibres (because of the colour of myelin) and are found in the white matter of the brain and spinal cord.
• In MS the immune system attacks and damages myelin, oligodendrocytes (myelin producing cells) and axons.
• This in turn interferes with conduction of impulses along the nerve fibre, resulting in a range of disabling neurological symptoms that vary from one person to another depending on where the damage has occurred.
• There is no cure and symptoms can ‘come and go’ (relapse) and vary with each individual.
• The CNS can restore function by remyelinating the axons.
  • After remyelination, function is restored but may not be as quick or as efficient.
  • Permanent loss of function in MS is caused by failure to remyelinate, which in turn leads to axonal loss and neuronal death.

Types of multiple sclerosis

Four disease courses have been identified in MS.

Lublin F, Reingold S, Cohen J et al. Defining the clinical course of multiple sclerosis: the 2013 revisions. Neurology 2014;83:278–286.

Relapsing-remitting MS (RRMS)

• Characterised by clearly-defined periods of worsening neurological function (relapse), which are followed by periods of partial or complete recovery (remission) without apparent disease progression.
• Around 85% of patients with MS have RRMS at the time of diagnosis.

Secondary-progressive MS (SPMS)

• Occurs in around 60–70% of patients with RRMS, typically 10–30 years after initial onset.
• SPMS is characterised by gradual disease progression with or without relapses.

Primary-progressive MS (PPMS)

• Characterised by steady disease progression and worsening neurological function from onset, with no distinct periods of relapse or remission.
• Around 10% of MS patients have PPMS.

Progressive-relapsing MS (PRMS)

• Characterised by steadily worsening neurological function from the onset with occasional relapses.
• Around 5% of people with MS have PRMS.

The Pharmaceutical Journal, PJ, 21 February 2015, Vol 294,

No 7850;294(7850):DOI:10.1211/

PJ.2015.20067861