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 that 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.