Multiple sclerosis (MS) is a chronic condition that causes nerve damage. The four main types of MS are:

  • clinically isolated syndrome (CIS)
  • relapsing-remitting MS (RRMS)
  • primary-progressive MS (PPMS)
  • secondary-progressive MS (SPMS)

Each type of MS leads to different prognoses, levels of severity, and treatment methods. Keep reading to find out how PPMS differs from RRMS.

PPMS is one of the rarest types of MS, affecting about 15 percent of everyone diagnosed with the condition. While other MS types are characterized by acute attacks, called relapses, followed by periods of non-activity, called remission, PPMS causes gradually worsening symptoms.

PPMS can change over time. A period of living with this condition can be classified as:

  • active with progression if there are worsening symptoms or new MRI activity or relapses
  • active without progression if symptoms or MRI activity is present, but symptoms have not become more severe
  • not active without progression if there are no symptoms or MRI activity and no increasing disability
  • not active with progression if there are relapses or MRI activity, and the symptoms have become more severe

What are common PPMS symptoms?

PPMS symptoms can vary, but typical symptoms include:

  • vision problems
  • difficulty talking
  • problems walking
  • trouble with balance
  • general pain
  • stiff and weak legs
  • trouble with memory
  • fatigue
  • trouble with bladder and bowel
  • depression

Who gets PPMS?

People tend to get diagnosed with PPMS in their 40s and 50s, while those diagnosed with RRMS tend to be in their 20s and 30s. Men and women are diagnosed with PPMS at the same rates, unlike with RRMS, which affects mostly women.

What causes PPMS?

The causes of MS are unknown. The most common theory suggests that MS begins as an inflammatory process of the autoimmune system that causes damage to the myelin sheath. This is the protective covering that surrounds the nerves of the central nervous system.

Another theory is that it’s an immune response triggered by a viral infection. Later, nerve degeneration or damage occurs.

Some evidence suggests that primary-progressive MS is part of the clinical spectrum of MS and isn’t different from relapsing MS.

What is the outlook for PPMS?

PPMS affects everyone differently. Because PPMS is progressive, symptoms tend to get worse rather than better. Most people have trouble walking. Some people also have tremors and vision problems.

What treatments are available for PPMS?

Treatment of PPMS is more difficult than RRMS. It includes using immunosuppressive therapies. They may offer temporary help but can only be safely used for a few months to a year at a time.

Ocrelizumab (Ocevus) is the only FDA-approved medication to treat PPMS.

There’s no cure for PPMS, but you can manage the condition.

Certain disease-modifying drugs (DMDs) and steroids can help manage symptoms. Maintaining a healthy lifestyle that includes eating a well-balanced diet and exercising may help. Rehabilitation through physical and occupational therapy may also help.

RRMS is the most common type of MS. It affects around 85 percent of all people diagnosed with MS. Most people are first diagnosed with RRMS. That diagnosis typically changes after several decades to a more progressive course.

The name relapsing-remitting MS explains the course of the condition. It typically involves periods of acute relapses and periods of remissions.

During relapses, new symptoms can present, or the same symptoms can flare up and become more severe. During remissions, people can have fewer symptoms, or the symptoms can be less severe for weeks, months, or years.

Some RRMS symptoms can become permanent. These are called residual symptoms.

RRMS is classified as:

  • active when there are relapses or lesions found on an MRI
  • not active when there are no relapses or MRI activity
  • worsening when symptoms get progressively more severe after a relapse
  • not worsening when symptoms do not get progressively more severe after a relapse

What are common RRMS symptoms?

Symptoms vary for each person, but common RRMS symptoms include:

  • problems with coordination and balance
  • numbness
  • fatigue
  • inability to think clearly
  • problems with vision
  • depression
  • problems with urination
  • trouble tolerating heat
  • muscle weakness
  • trouble walking

Who gets RRMS?

Most people are diagnosed with RRMS in their 20s and 30s, which is younger than a typical diagnosis for other MS types, such as PPMS. Women are twice as likely to be diagnosed than men.

What causes RRMS?

One common theory is that RRMS is a chronic autoimmune condition that occurs when the body starts to attack itself. The immune system attacks the central nervous system’s nerve fibers and the insulating layers, called myelin, that protect the nerve fibers.

These attacks cause inflammation and create small areas of damage. This damage makes it difficult for nerves to carry information to the body. RRMS symptoms vary depending on the location of the damage.

The cause of MS is unknown, but there are likely both genetic and environmental triggers for MS. One theory suggests a virus, such as Epstein-Barr, might trigger MS.

What is the outlook for RRMS?

This condition affects each person differently. Some people may live a relatively healthy life with only rare relapses that don’t cause significant complications. Others may have frequent attacks with progressive symptoms that eventually lead to severe complications.

What are RRMS treatments?

There are several FDA-approved medications available to treat RRMS. These medications tend to reduce the occurrence of relapses and the development of new lesions. They also slow the progression of RRMS.

Although PPMS and RRMS are both types of MS, there are clear differences between them, such as:

Age of onset

A PPMS diagnosis typically occurs in people in their 40s and 50s, while RRMS affects those in their 20s and 30s.

Causes

Both PPMS and RRMS are caused by inflammation and immune system attacks on myelin and nerve fibers. RRMS tends to have more inflammation than PPMS.

Those with PPMS have more scars and plaques, or lesions, on their spinal cords, while those with RRMS have more lesions on the brain.

Outlook

PPMS is progressive with symptoms getting worse over time, while RRMS may present as acute attacks with long periods of inactivity. RRMS may develop into a progressive type of MS, called secondary progressive MS, or SPMS, after a certain time.

Treatment options

While Ocrelizumab is the only FDA-approved medication to treat PPMS, there are several that may help. There are also more medications that are being researched. RRMS has over a dozen approved treatments.

Patients with both PPMS and RRMS may benefit from rehabilitation with physical and occupational therapy. There are many medications doctors can use to help people with MS manage their symptoms.