Secondary Progressive Multiple Sclerosis tends to be a more steady progression of the apparent neurological damage to the CNS with or without the relapses or minor remissions and more periods of time where the symptoms seem to level off that are seen in the Relapse-Remitting type of ms. It appears that those that develop Secondary Progressive MS have already been previously diagnosed with Relapse-Remitting MS and have struggled with ms for 2 to 40 years before they develop Secondary Progressive ms.  The relapses and remissions that appeared during the time after the initial diagnosis tend to gradually disappear after the Relapse-Remitting MS type turns into the secondary progressive ms type.

Once the Secondary Progressive form of the disease appears, the person becomes more disabled more quickly than they had during the Relapse-Remitting ms, although the appearance of the more severe disability can be much slower in some individuals. In spite of the fact that the majority of people that have been diagnosed with Relapsing and Remitting Multiple Sclerosis will most likely develop Secondary Progressive ms, it appears that only 25% of people with MS will get to the point where they need to use a wheelchair.

Secondary Progressive Multiple Sclerosis tends to be associated with less scarring and lesions appearing that in Relapse Remitting MS, but overall the resulting nerve damage appears to be worse in the Secondary Progressive Multiple Sclerosis than in the Relapse Remitting, as the disease continues to progress.  At any one point in time, the Secondary Progressive form of MS accounts for 30% of all people that have been diagnosed with Multiple Sclerosis.