What type of MS do you have?

Type of MS

You should be able to classify yourself as having either relapsing or non-relapsing progressive MS.

85-90% of MSers start with so called relapse onset MS, i.e. they have a definite attack that is usually followed by a period of recovery that can be complete or incomplete. When you have only one attack you may be labelled as having a clinically isolated syndrome (CIS). This means that you don't fulfill the current diagnostic criteria for having full blown MS, but you are at risk of developing further attacks and MS in the future. Once you have more attacks then you are usually diagnosed as having MS.

After a variable period of time people with relapse-onset MS may notice worsening of neurological function without improvement. When this occurs it is called secondary progressive MS (SPMS). Please note that SPMS can occur with or without superimposed relapses.

A small number of MSers (10-15%) will present with worsening neurological function without a prior history of relapses. This type of MS is called primary progressive MS (PPMS). Interestingly, a number of PPMSers go onto have relapses and these people have been referred to as having progressive-relapsing MS (PRMS).

Rarely someone may present with worsening neurological function, similar to PPMS, but have a prior history of just one relapse. This was referred to in the past as single-attack progressive MS. Most MSologists classify these patients as having SPMS.

When we refer to people with relapsing MS it capture all MSers who are still having relapses, i.e. within the last 2 years, and includes people with RRMS, R-SPMS and PRMS. In comparison, non-relapsing progressive MS refers to SPMS and PPMS. These MSers should have no history of recent relapses, i.e. in the last 2 years. In the past non-relapsing progressive MS was referred to as chronic progressive MS (see below).

Why is this important? Different DMTs are licensed for different types of MS and many treatment guidelines specifically state the type of MS a particular drug can be used for.

To be honest with you what is important is know if your MS is active or inactive. This is covered in a different section on this microsite.

Is MS one or more diseases?

In the past MS was one disease, i.e. you either had MS or you did not have MS. The stages of MS were referred to as early relapsing MS or chronic progressive MS, but MS was still one disease.

However, when disease modifying therapies were developed MS was split into multiple sub-types. The splitting of MS into multiple diseases was driven by commercial considerations and allowed interferon-beta to be licensed under the orphan-drug act in the United States. To be classed as an orphan disease there has to be less than 200,000 people diagnosed with the disease in the US. By dividing MS into relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), primary progressive MS (PPMS) and later clinically-isolated syndromes (CIS) ensured that each category had fewer than 200,000 people. Since then progressive-relapsing (PRMS) and radiologically-isolated syndrome (RIS) categories have also been added. These classifications tend to arbitrary and overlap with each other and there is no biological basis to support MS being more than one disease.

From a treatment perspective it is more important to know if you disease is active. This means there is evidence of ongoing inflammation in the brain and spinal cord. If you are having relapses, or are developing new lesions on MRI, or you have raised neurofilament light levels (NFL) in your cerebrospinal fluid (CSF) your MS is active. Most people will accept that you have to have had a relapse in the last 2 years and/or have had MRI evidence of activity in the last 12 months and/or raised CSF NFL levels measured in the last 6 months to be called active. Please note these definitions of activity are quite arbitrary and tend to have been set by the entry criteria for clinical trials of disease-modifying therapies, as a result they tend to be incorporated into clinical guidelines. The general consensus is that if your MS is active you are likely to respond to anti-inflammatory therapies.

The term progressive MS is entrenched in the field and refers to the stage of MS when your disability gets worse independent of relapses and possibly focal inflammatory lesions. I say possibly because our current MRI scan don't report out the presence of new or enlarging microscopic lesions but only those that are larger than 3-4 mm in size. CSF NFL measurements have the advantage of being

This may happen because of delay death of axons from persistent demyelination or slow burn. Axons that are persistently demyelinated are vulnerable to die prematurely for many reasons; one reason is that it takes more energy to conduct nerve impulses across demyelinated nerve segments. The lack of energy results in the axon being 'overworked' as a result it dies prematurely. This is one reason why remyelination therapies remain an important treatment strategy in MS. Slow burn refers to the so called toxic mircoenvironment that exists in some MS lesions after the initial inflammatory attack resides. The immunological and chemical mediators that are continuously produced in these lesions results in continued loss of neurons and axons that runs its course over months to years; therefore worsening of disability, without active disease could be due to the dying off of axons or neurons that were damaged in the past. These slow burn lesions are often referred to chronic expanding lesions or CELs and have a rim of 'hot microglia' at their edges.

Another issue is premature ageing. What protects people from age-related neurodegeneration is so-called reserve capacity that is related to brain and cognitive reserve. MS reduces both brain reserve (size of the brain) and cognitive reserve (education and ability to learn). Therefore MSers are on average more susceptible to ageing; hence some of the late worsening of disability could simply be superimposed age-related neurodegeneration. This is another reason for managing MS holistically and targeting so called non-MS related issues to maximise brain health.