Because the transition from a relapsing-remitting course to a more progressive one is a gradual process, the doctor will not be able to tell exactly when it is happening. If a person’s symptoms are worsening, the challenge for the doctor is to determine whether:
- The worsening is left over from the last relapse. In other words, permanent but stable damage remains after the inflammatory attack has ended, which would mean that the person is still in the RRMS phase of the illness; or
- The disease is continuing to worsen even though the last inflammatory attack has ended, which would mean that the person has transitioned to the SPMS phase.
The physician will use a variety of strategies, including a careful history of the changes in a person’s symptoms, the neurologic examination, and repeat magnetic resonance imaging (MRI) scans, to try and determine what is happening with the person’s disease.