What Is Secondary Progressive Multiple Sclerosis?

In SPMS, you may not get any break in your symptoms, unlike RRMS, when you had flare-ups that came and went. But your doctor can suggest medicine to help manage them.

About 85% of people with MS start with the relapsing-remitting form. They get attacks of symptoms called relapses, followed by symptom-free periods called remissions.

During relapses, your immune system — your body’s defense against germs — causes inflammation that damages the protective coating around nerve fibers. This disrupts the flow of nerve signals to and from the brain and spinal cord. It leads to symptoms like tiredness, numbness, and weakness.

Then the immune system stops attacking. Your symptoms improve or disappear, and you go into remission. Relapses and remissions alternate over time.

In SPMS, your symptoms steadily get worse instead of coming and going. You might still have relapses, but they don’t happen as often.

It’s not clear exactly why RRMS changes to SPMS. Some researchers think it happens because of nerve damage that occurred earlier in the disease.

Not everyone with the relapsing-remitting form of the disease will get SPMS. Doctors don’t know for sure who will and who won’t, and how quickly it will happen.

You’re more likely to change to SPMS if:

A small number of people start out with SPMS. They may have had RRMS first, but it wasn’t diagnosed or their symptoms were too mild to notice.

Before disease-modifying drugs were available, half of people with RRMS changed to SPMS within 10 years.

New treatments have altered the course of MS. Today these drugs can slow MS and delay the move towards SPMS, although doctors don’t know how much they delay it.