• The three relapsing forms of multiple sclerosis (MS) are clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS), and active secondary progressive MS (SPMS).
• Relapsing forms of MS can transition to more progressive forms of the disease.
• Long-term treatment with disease-modifying therapies (DMTs) is the most effective way to delay MS progression.

Multiple sclerosis can take different disease courses, and each represents a different type of MS. Only certain types of MS have a risk of relapses — also known as flare-ups, exacerbations, or attacks. Relapses are periods of new or worsening symptoms of MS. Doctors sometimes disagree about the exact nature of MS, but relapsing forms are often treated using the same medication options.

Understanding the Relapsing Forms of MS

There are three types of relapsing MS: clinically isolated syndrome, relapsing-remitting MS, and active secondary progressive MS.

Clinically Isolated Syndrome

Clinically isolated syndrome is often the first episode of symptoms a person will experience that eventually lead to a diagnosis of MS. CIS is diagnosed after neurological symptoms present for at least 24 hours. These symptoms must be due to demyelination (damage to the myelin that sheathes nerve fibers) or inflammation in the central nervous system (CNS).

CIS is a condition that can convert (or progress) to MS. The risk of conversion is often predicted based on the quantity and size of brain lesions, as seen on initial baseline MRI scans. CIS is usually diagnosed in people between the ages of 20 and 40. Effective treatment soon after a diagnosis of CIS is important to delay the conversion to MS.

Relapsing-Remitting Multiple Sclerosis

Relapsing-remitting MS is the most common form of MS. However, no two people experience RRMS the same way. This is because lesions can occur in different locations within the CNS, affecting different functions.

RRMS is characterized by defined attacks of new symptoms or symptoms worsening in severity. There are several risk factors for RRMS. Women are approximately two to three times more likely than men to be diagnosed with RRMS, according to Mayo Clinic. The age of onset for RRMS is similar to that of CIS — between ages 20 and 40. However, children can also be diagnosed with this course of MS. Genetics pose another risk factor, as RRMS can run in families.

Active Secondary Progressive Multiple Sclerosis

After a period of time, RRMS can progress to secondary progressive MS. In people with progressive disease, neurological symptoms continue to get worse, without clear periods of remission. SPMS is considered active if relapses continue to occur and inactive if there have been no relapses for a while. According to the National Multiple Sclerosis Society, without the use of approved disease-modifying therapies, 50 percent of people diagnosed with RRMS will likely transition to SPMS within 10 years, and 90 percent tend to transition within 25 years.

Although CIS, RRMS, and SPMS are distinct forms of relapsing MS, they are often grouped together and share similar treatment options.

Treatment Options for Relapsing Forms of MS

Disease-modifying therapies are the primary defense against progression in relapsing forms of MS. About 20 medications have been approved for the treatment of relapsing forms of MS. Research suggests DMTs can:

• Reduce the frequency of MS relapses
• Limit new MS activity, such as lesions or plaques on the brain and spinal cord, as shown on MRI scans
• Slow disease progression, including conversion from CIS to RRMS or from RRMS to active SPMS

People diagnosed with any type of relapsing MS should discuss DMTs with a doctor as soon as possible. Early treatment can make a positive difference in slowing the progression of MS.

Read What To Tell Your Physician About Relapsing MS Treatments and 14 Things To Ask.

Classes of DMTs for Relapsing Forms of MS

Different classes of medications are used as disease-modifying therapies in cases of relapsing MS. Each class works in a different way, and your neurologist can help you decide on the best treatment option for you.

Classes of drugs used as DMTs for MS include:

• Interferons, such as interferon beta 1a (Avonex) and interferon beta 1b (Betaseron)
• Monoclonal antibodies, such as ocrelizumab (Ocrevus) and natalizumab (Tysabri)
• Fumarates, such as dimethyl fumarate (Tecfidera) and diroximel fumarate (Vumerity)
• Cladribine (Mavenclad), an adenosine analog
• Sphingosine-1-phosphate receptor modulators, such as fingolimod (Gilenya) and siponimod (Mayzent)
• Pyrimidine synthesis inhibitors, such as teriflunomide (Aubagio)

Delaying MS Progression

MS is a debilitating disease that will progress — or continue to worsen — as time goes by. There is not yet a cure for MS. However, beginning a DMT treatment as early as possible following diagnosis can help delay the progression to more debilitating forms of MS.

There are many new MS drugs. At present, it is largely unknown how these medications might delay or lower the risk of MS progression in the long term. Long-term treatment with a DMT is the single most important factor in delaying MS progression.

Talk With Others Who Understand

MyMSTeam is the social network for people with multiple sclerosis and their loved ones. On MyMSTeam, more than 195,000 members come together to ask questions, give advice, and share their stories with others who understand life with MS.

Are you living with a relapsing form of multiple sclerosis? Do you worry about progression? Share your experience in the comments below, or start a conversation by posting on your Activities page.