Well over a decade ago, a group of multiple sclerosis (MS) specialists — researchers and clinicians — got together to develop a common language for talking about MS. The group identified the following four disease courses, as illustrated in the figure:
Relapsing-remitting MS (RRMS): MS begins as a relapsing-remitting disease about 85 percent of the time. RRMS is characterized by unpredictable periods of worsening (called relapses, exacerbations, or attacks) followed by remissions. A remission may be complete, meaning that the person returns to his or her pre-relapse level of functioning, or partial, meaning that some of the symptoms are likely to be permanent.
Secondary-progressive MS (SPMS): Within about ten years, approximately 50 percent of those who are diagnosed with RRMS transition to SPMS, which is characterized by a steady (but not necessarily rapid) progression of disability without any remissions. Within about 25 years, a large majority of people make this transition. These folks generally have fewer or no relapses as time goes on.
Primary-progressive MS (PPMS): For about 10 percent of people, MS progresses right from the beginning, without any relapses or remissions. PPMS seems to differ from RRMS and SPMS in terms of its underlying disease process — it has less inflammatory action going on in the brain and spinal cord and more tissue degeneration and destruction early on. These differences may be the reason that the current treatments for MS — which mainly target the inflammation — work much better in relapsing forms of MS than they do in PPMS.
Progressive-relapsing MS (PRMS): A very small number of people (less than 5 percent) are diagnosed initially with a progressive form of the disease but then experience some relapses down the road.
Even though these categories may seem nice and neat, they really aren’t. Within each of the groups is a tremendous variability, so don’t be surprised if your MS doesn’t quite fit any of the descriptions outlined here.
For example, regardless of their disease course, some folks may experience very mild, stable MS (sometimes referred to as benign MS), while others may have a more rapidly disabling course. Unfortunately, no one can predict for sure whose MS is going to do what, which has led most MS experts to conclude that early treatment with one of the available medications is the best way to hedge your bets. So even if your MS appears benign at the outset, starting treatment early is your best protection against future progression.
MS symptoms can involve virtually any sensory or motor function that’s controlled by the central nervous system. This means that the list of possible symptoms is long — including fatigue (by far the most common), visual changes, walking problems, and tremor; bladder and bowel problems, sexual difficulties, sensory changes, and speech and swallowing problems; and mood changes and problems with thinking and memory.
Most symptoms tend to come and go, but some may come and stay. And they can range from mild to quite severe. The good news is that most people don’t develop all of these symptoms, and most of the symptoms are treatable.
MS symptoms don’t show up in any particular order. Often, however, visual changes are what bring someone to the doctor. Then, once in the doctor’s office, it’s pretty common for someone to remember an episode of one or more of these symptoms during high school or college that came and went without anyone paying much mind. That’s why your doctor asks you so many questions and takes such a careful medical history when trying to arrive at a diagnosis.
