Multiple Sclerosis? What Type Are You?

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Rose is a rose is a rose." ~ Gertrude Stein

A rose is a rose, but can we say MS is MS? After all, MS affects the autoimmune central nervous system of every person who has MS. But after that it gets a bit murky.

Just as a rose is identified by characteristics such as color, size and fragrance, so is each person's MS symptoms unique based on symptom clusters, reactions, time lines, the course of the disease and any number of other idiosyncrasies. So yes, MS is MS, but not exactly. There are different categories or types of MS that provide us with some degree of understanding why symptoms of people with MS differ so greatly.

It is sometimes difficult to know if a new symptom is because of MS, or if it is something totally unrelated. It is at least as difficult to determine what type of MS applies to us at any given time. Just as symptoms may come and go, we may evolve from one type to another as a regular course of this confusing disease. Most of us eventually get a handle on our symptoms, but many of us do not know about types, and perhaps there is good reason.

Even though there are four basic types typically recognized by the international medical community, there are more subtypes and labels. The same type may be called by different labels based on time. There are even a couple of conditions once considered to be MS that have since been determined to be separate diseases all together, although they are closely related. Who wouldn't be confused?

Lets look at the types and labels of MS, beginning with diagnosis:

Probable MS
This is a label many of us have heard. Probable MS is the first step of diagnosis, the common entrance for all other types.

MS is usually diagnosed only after two or more attacks, and two or more lesions found on an MRI over time, as described in the Revised McDonald Criteria. Before that criteria is satisfied, when MS is suspected, even strongly suspected, it is first labeled as Probable MS. After time, tests, and multiple attacks, the probable becomes definite, but that is only part of the answer.

When I was diagnosed, I was simply told I have MS. However, MS is not always just MS. There was still a question of type. MS may be RRMS, SPMS, PPMS, or PRMS.

MS Types by Occurrence

The percentage numbers given do not add up to 100 because they are approximate and often reported inaccurately. Also, types evolve from one to another, they are mislabeled, misdiagnosed, or not diagnosed at all. Just as we do not know why we get MS, little or nothing is known about why we develop one type or another, or why some people with Relapsing MS never move on to Secondary Progressive, or why some people experience benign periods, or . . . well. you get the idea.

However, we do know the first step of diagnosis is Probable MS. After an undetermined amount of time and unpredictable events, when probable becomes definite, the question of MS Types begins.

Why do we need to know? If we know what type of MS we have, we have a better idea what to expect, especially as far as the course of the disease. We know about clinical trials studying our particular MS type and treatment options available to us, and those that are not. We know how to talk to the doctor, and we understand better when the doctor responds.

The more knowledge we have about our incomprehensible disease, the monster that has invaded our lives, the more we are empowered to accept and handle it.

Relapsing/Remitting MS (RRMS)
Most people, including me, who are diagnosed with MS have the Relapsing/Remitting type. This is the MS that is most recognized, identified by periods of relapse followed by periods of remittances or complete recovery. At any given time, approximately 55%-85% of MSers have RRMS. Relapsing/Remitting MS is the type most MSers have, at least at first,and these are the ones who often know their type -- but not always. Clinical trials and disease-modifying drugs most often apply to RRMS.

Chronic Progressive
Until recently, anyone who did not have RRMS was told they have Chronic Progressive MS. All of us have Chronic MS. This is label that includes all progressive forms of MS.

In Progressive MS, there is a gradual worsening of symptoms. Progression is measured by loss of function as well as increase in lesions. However, Chronic Progressive MS is further characterized by defined, distinctive subtypes.

Secondary Progressive MS (SPMS)
Just as it takes time after the initial symptom presentation to get a definite diagnosis of MS, time is also a major factor in developing and identifying a type as Secondary Progressive. It is often difficult to determine exactly when the MSer crosses the threshold from RRMS to SPMS, but the difference between the types is clear.

When Relapsing/Remitting precedes a progressive form of MS, it is Secondary Progressive. That time period varies from as short as two years, to as long as forty years. At any given time, Secondary Progressive accounts for 30-40% of all MSers.

In the beginning of Secondary Progressive MS, there is a gradual worsening between relapses. There may still be relapses and remittances, but not as strong or obvious as before. After awhile there are no relapses and definitely no recoveries, but general progression of the symptoms continues. That is Secondary Progressive MS. This is now my MS.

Primary Progressive MS (PPMS)
If there is no period of initial Relapsing/Remitting before a progressive course, it is likely to be Primary Progressive MS. Somewhere between 10% and 15% of all MSers have PPMS. It is a steady progression of greater affliction with little or no recovery. Basically, Primary is quite similar to Secondary, without a previous period of Relapsing/Remitting.

Primary Progressive MS is generally diagnosed about one or two years after the initial presentation followed by progression of symptoms and some degree of disability. Though similar to Secondary, is unique. It is identified usually in late 30s or early 40s, affecting men as likely as women, and it usually attacks the spinal cord rather than the brain.

Progresssive Relapsing (PRMS)
Around 3-5% of MSers have a steady progression of neurological damage accompanied by clear periods of relapse followed by significant recovery. This form is similar to Relapsing/Remitting, but with the addition of accumulated damage between relapses. Sometimes this course of the disease progression is thought to be Primary until punctuated with relapse, and remittance ranging from full recovery to very little.

Some of the medical community believe a clear progression since the beginning with clear relapse and recovery periods is actually a variation of PPMS, if no identifiable period of Relapsing/Remitting preceded it. A period of this type also describes the overlap between RRMS and SPMS, easing the change from Relapsing/Remitting to Secondary Progressive.

These types of MS are recognized internationally. However, there are other terms used when diagnosing or just talking about MS.

Benign MS is characterized by a long period of little activity after the first attack. In Benign MS, people may remain fully functional though an MRI shows evidence of lesion. After an initial attack, MS may be considered benign after 10 or 15 years of no advanced functional disability. When symptoms flare, it is often reclassified as Secondary Progressive. The benign period may actually be nothing more than a long remission in a form of Relapsing/Remitting MS.

Benign is possibly a misleading term because it implies the severity of the disease is minimal. It may actually indicate that the severity is simply being delayed. As many as 20% of all MSers are considered Benign.

The malignant form is extremely rare and may also be called Marburg's Variant or Acute MS. It is a particularly aggressive form of Primary Progressive that progresses quite fast and results in severe disability.

Transitional Progressive
This term is also used only rarely, characterized by an initial attack followed by a long remission, then an obviously progressive course.

Devic's Disease or Syndrome
Devic's Syndrome is characterized by severe optic neuritis in both eyes and severe inflammation in a single section of the spinal cord. As the disease progresses, symptoms include motor difficulties, urinary, bowel, and sexual problems. Although at one time it was considered a type of MS, now it is generally considered a separate disease closely related to MS.

Balo's Concentric Sclerosis
Again, this is a disease separate but very similar to MS. It is identified by an MRI that shows concentric rings of intact myelin and demyelinized zones. It is very rare, and prevalent mostly in the Far East.

Next time I'll talk in more detail about Primary and Secondary Progressive.

Notes and Sources:
Gertrude Stein first used the phrase in a poem, Sacred Emily.

MS Types by Occurrence chart by GRJenkin
NMSS Includes charts representing typical disease courses for each type.
Geocities - Geocities presents a nice summary of MS types.
Health Care Guides - Another clear summary of types.
Revised McDonald Criteria