Classification of Multiple Sclerosis

Classification of MS

The sub-types of MS include:

Relapsing-Remitting MS (RRMS)

85% of patients who develop MS have RRMS
Severity varies greatly in from individual to individual.
Initial average annual relapse rate of about 2-2.5, dropping to approximately one per year.
Frequent relapses, especially at disease onset, considered as poor prognostic sign.
At 10 years after disease onset 50% of patients will enter the SPMS phase, at 20 years this will rise to 80%.

Progressive-Relapsing MS (PRMS)

Can be identified as worsening Relapsing-Remitting MS (progressive disease with obvious relapses).
Important to identify in terms of treatment. Whether the patient with PRMS is already on disease modifying therapies or not, switching to other treatments such as Tysabri or Mitoxantrone may be crucial in prevention of further disease activity and slowing down the evolution from PRMS to SPMS.

Secondary-Progressive MS (SPMS)

Defined as progression of clinical disability (with or without relapses and minor fluctuations) after a relapsing-remitting onset.
Disability progresses even in between relapses.
Establishing when patients are converting from RRMS to SPMS can be difficult and only become apparent over a significant length of time.

Primary-Progressive MS (PPMS)

Approximately 10%-15% of the MS population and, as opposed to other forms of MS, with no female propensity.
Progressive from onset without any discernible relapses or remissions.
Usually later age of onset (40’s onwards), though in rare cases can occur at an earlier age.
Typically presents with an increasing spastic gait already affecting quality of walking.
Poorer prognosis; it takes approximately 6 years to reach EDSS of 6.

Benign MS

Isolated attacks with complete recovery, with little or no accumulation of disability.
The attacks may be separated by 10 years or more.
Often goes undiagnosed for several years and in many instances, is diagnosed post-mortem.

See also:

Diagnosis of MS

Reference:

1- HSE (September 2012). Handbook for nurses and midwives caring for people with Multiple Sclerosis. A guide to support practice. Available at: http://www.hse.ie/eng/about/Who/ONMSD/practicedevelopment/Multiple%20Sclerois%20Care/Handbook%20for%20non%20Specialist%20Nurses%20%20MS.pdf. Accessed 13/3/2014