Types of MS

[shoshin]

We seem to have this discussion interminably and yet the types of MS still seem elusive. Just to satisfy my own curiosity, I got my hands on a copy of the article on which the current four clinical types are based:

Defining the clinical course of multiple sclerosis: results of an international survey by Fred D. Lublin and Stephen C. Reingold for the National Multiple Sclerosis Society (USA) Advisory Committee on Clinical Trials of New Agents in Multiple Sclerosis. In Neurology. 1996 Apr;46(4):907-11. http://www.ncbi.nlm.nih.gov/pubmed/8780061

Anyway, up until that point clinical trials were hampered by a lack of agreement on the types of MS and the definitions of those types. It was thought that since MS is such a heterogeneous disease, mixing up different types in one clinical trial would lead to inaccurate results. Given the lack of biomarkers for MS (e.g., something in the blood or the MRI that definitely would mark MS and show progression; we still lack biomarkers today), some researchers decided to undertake a survey and try to come up with types and definitions based on clinical patterns.

So this is where we get the four clinical patterns that you hear so much about--basically a survey of MS experts to try to come up with definitions that could be used to split up patients into groups for clinical trials. They used consensus to arrive at a standardized terminology, but the definitions were not unanimously agreed upon and it's still not clear whether anything of biological significance underlies these clinical courses. There are other ways to classify MS, such as by pathological types of lesions (however, this is not very practical for clinical trials as it requires a brain biopsy or an autopsy of a dead brain).

Just for the record, I'll summarize what they say about the four clinical types, although I'm not sure this really makes it any easier to map to our own less clear-cut experiences.

**RRMS (relapsing-remitting multiple sclerosis): "clearly defined disease relapses with full recovery or with sequelae and residual deficit upon recovery; periods between disease relapses characterized by a lack of progression.

"The defining elements of RR-MS are episodes of acute worsening of neurologic function followed by a variable degree of recovery, with a stable course between attacks. Although a clear majority (105/134) of responses included this definition, some (16/134) favored using the term relapsing-remitting only for those who fully recover between relapses. However the lack of evidence for a biological difference between those who recover fully and those who recover partially and potential differences in the vigor with which one might seek to determine the extent of recovery (clinical examination, evoked potentials, and so on) favored the more inclusive definition."

**PPMS (primary progressive multiple sclerosis): "disease progression from onset with occasional plateaus and temporary minor improvements allowed.

"The essential element in PP-MS is a gradual nearly continuously worsening baseline with minor fluctuations but no distinct relapses."

**SPMS (secondary progressive multiple sclerosis): "initial RR course followed by progression with or without occasional relapses, minor remissions, and plateaus.

"SP-MS may be seen as a long-term outcome of RR-MS in that most SP patients initially begin with RR disease as defined here. Once the baseline between relapses beings to progressively worsen, the patient has switched from RR-MS to PP-MS."

**PRMS (progressive-relapsing multiple sclerosis): "progressive disease from onset, with clear acute relapses, with or without full recovery; periods between relapses characterized by continuing progression."

They also briefly discuss definitions for two types of clinical severity, malignant and benign, but did not find an overwhelming consensus.

FWIW.

sho

[shoshin]

Thanks, Lulu, for picking up that typo. I did indeed mean SPMS.

PRMS is pretty rare and I have read that some researchers don't consider it functionally different or different in outcome from PPMS and thus don't think a separate category is needed for clinical trials. It seems to refer people who have an initially progressive course and then after some time (even a lot of time) have one or more relapses superimposed on their progression.

sho

[Lulu54]

I went and looked - PRMS is the form that fewer than 5% of MS patients have ....

[Lulu54]

Interesting to know where the categories came from - thanks!

I'm assuming there is a typo in this paragraph and the very end should read *switched from RR-MS to SP-MS* and not PP-MS  

"SP-MS may be seen as a long-term outcome of RR-MS in that most SP patients initially begin with RR disease as defined here. Once the baseline between relapses beings to progressively worsen, the patient has switched from RR-MS to PP-MS."

We rarely read anything about Progressive -Relapsing MS, so I have to wonder if that is still considered a category?    Or is that the fast moving, almost always fatal form?

thanks again,
Lulu