The symptoms that accompany a relapse are usually dramatic and debilitating – I have completely lost vision in one eye with optic neuritis, I have gone from being able to walk quickly to having to clutch furniture or another person to get across the room, and I have had such intense pain from the "MS hug" that I could not sleep. These symptoms came on quickly and intensified within a day or two.
When I have had a relapse, two main questions were in my mind: 1) When will these immediate symptoms be gone? 2) What effect will this relapse have long-term? While my immediate symptoms responded well to a course of Solu-Medrol, I still wonder what kind of impact the relapse had on my future disability.
I was lucky enough to attend a session at ECTRIMS 2012 called "Controversies in the Natural History of MS," where Antonio Scalfari from the Division of Neuroscience of Imperial College in London presented data on the relationship between relapses and sustained disability, using information from different databases of MS patients.
Typically, relapsing-remitting MS begins with a higher number of relapses at the beginning of the onset of the disease. Research is now showing that the relapses that people have in the first year or two may be the most important relapses in terms of telling us what our disease course may be.
How do relapses predict long-term disability?
Overall, people with more early relapses in the first two years after diagnosis have a shorter time to diagnosis of secondary progressive MS. Those that had 3 or more relapses in that time are almost 3 times more likely to progress to secondary progressive MS (SPMS) than the people who only had one relapse.
One study showed that people who had one relapse in the first 2 years took an average of 22.7 years to reach a score of 6.0 of the Expanded Disability Status Scale – EDSS (the point when assistance, such as a cane, is needed to walk), while those people who had 3 or more relapses in the first two years reached EDSS of 6.0 in 15.1 years.
However, the time from EDSS 3.0 (the average EDSS score when SPMS is diagnosed) to EDSS 6.0 is notaffected by early relapses.
Additionally, the number of relapses a person has after the first two years has almost no effect on progression to SPMS.
It turns out the most important factor in predicting progression to EDSS 6.0 is time to reach SPMS. Once SPMS is reached, relapse history does not matter, as disability accumulates with pretty much the same speed.
What does this mean for individuals with MS?
Remember that not everyone with relapsing-remitting MS will convert to SPMS.
Although it is still not entirely clear whether disease-modifying therapies have an impact on long-term disability, to slow disability accumulation it is important to delay progression to SPMS. Since early relapses tend to speed time to SPMS conversion, it may be important that therapy be started early to attempt to prevent relapses early in the disease process.