A relapse can last for a few hours or several days. The symptoms can gradually worsen. RRMS is unpredictable. Some people go into remission without treatment.
At some point, many people with RRMS no longer have periods of remission or sudden relapses. Instead, their MS symptoms continue and worsen without any break. Continued, worsening symptoms indicate that RRMS has progressed to SPMS.
Similar symptoms exist within all forms of MS. But SPMS symptoms are far worse than RRMS. During the early stages of RRMS, symptoms are noticeable, but they aren’t necessarily severe enough to interfere with everyday activities. Once MS progresses to the secondary-progressive stage, symptoms become more challenging.