Multiple sclerosis (MS) is often diagnosed when people are in their 20s and 30s. The disease typically follows a pattern, moving through different variations or types over the years. This is because as you get older, your MS symptoms are likely to change.

MS damages myelin, the protective coating around nerves. This damage interrupts the flow of nerve impulses from the brain to the body. The greater the damage that’s done to the myelin, the more severe your symptoms will become.

Everyone with MS is different. How quickly your disease progresses and the symptoms you experience won’t necessarily be the same as someone else’s with the condition.

Your doctor can’t predict exactly how your disease will change over time. But advances in MS research are offering better treatments to slow the disease’s progression and improve the outlook for people living with MS.

The first attack

MS often starts with a single attack. Suddenly your vision becomes blurry, or your legs feel numb or weak. When these symptoms last for at least 24 hours and this is the first attack, they’re called clinically isolated syndrome (CIS).

CIS typically starts between ages 20 and 40. It’s caused by inflammation or damage to myelin in your central nervous system. CIS can be a warning of MS to come, but that isn’t always the case.

Between 30 and 70 percent of people with CNS will develop MS. If an MRI shows signs of brain lesions, MS is much more likely to develop.

Relapsing-remitting MS (RRMS)

Up to 85 percent of people with MS are first diagnosed with RRMS. It typically starts when people are in their 20s or 30s, although it can begin earlier or later in life.

In RRMS, attacks on myelin produce periods of symptom flare-ups called relapses. During a relapse, symptoms may include:

  • numbness or tingling
  • weakness
  • vision loss
  • double vision
  • fatigue
  • problems with balance

Each relapse can last from a few days to a few months. The exact symptoms and their severity can be different for each person.

After a relapse, you’ll enter a symptom-free period called remission. Each remission lasts for several months or years. The disease doesn’t progress during remission.

Some people stay in RRMS for many decades. Others progress to the secondary-progressive form within a few years. It’s impossible to predict how each person’s disease will act, but new treatments are helping to slow the progression of MS overall.

Primary progressive MS (PPMS)

About 15 percent of people with MS are diagnosed with the primary progressive form. PPMS usually appears during the mid to late 30s.

In PPMS, nervous system damage and symptoms steadily get worse over time. There are no real remission periods. The disease continues to progress, and it can eventually lead to problems walking and performing other daily activities.

Secondary-progressive MS (SPMS)

SPMS is the stage that follows RRMS. In this type of MS, myelin damage gets worse over time. You won’t have the long remissions that you had with RRMS. Increasing nervous system damage will lead to more severe symptoms.

In the past, about half of people with RRMS moved into the SPMS stage within 10 years, and 90 percent transitioned to SPMS within 25 years. With new MS drugs, fewer people are progressing to SPMS, and the transition is happening much more slowly. Experts don’t yet know how long these treatments can delay the progression to SPMS.

Takeaway

MS is a disease that starts early in life but progresses over time. Most people start with the relapsing-remitting form, alternating periods of symptoms called relapses with symptom-free periods called remissions.

Without treatment, the disease continues to the secondary-progressive form. Yet new and more effective treatments are slowing MS progression, sometimes for decades.