Primary progressive multiple sclerosis causes brain and nerve function to worsen. Symptoms do not go into remission then relapse. This is one of several forms that MS can take.

Multiple sclerosis (MS) is an autoimmune disease. It causes the immune system, which usually defends the body against infection and disease, to instead target the protective myelin coating that covers the nerves.

Around 15% of people with MS have primary progressive MS (PPMS).

In this article, we describe PPMS, its treatment, and additional strategies for managing symptoms.

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PPMS do not experience relapses in symptoms.

PPMS causes the function of the brain and central nervous system (CNS) to consistently worsen, without episodes of remission and relapse.

However, some people with PPMS experience temporary plateaus and sometimes minor reductions in symptoms.

For this reason, doctors add modifiers to better describe MS progression. The goal is to help a person receive the most effective treatment.

Below are these modifiers and their definitions:

  • Active: A brain MRI shows more lesions and wider disease activity.
  • Not active: Symptoms continue, but the disease is not causing further lesions.
  • With progression: Levels of disability are increasing and symptoms are getting worse.
  • Without progression: The disease is not causing further disability and symptoms are steady.

In people with relapsing-remitting MS or secondary progressive MS, symptoms develop and resolve cyclically. In a person with PPMS, the symptoms gradually grow more severe, without remission periods.

All types of MS typically damage the CNS. However, PPMS causes a distinct type of damage. It tends to cause fewer lesions on the brain and more lesions on the spinal cord, for example, compared with other forms of MS.

According to the National Multiple Sclerosis Society, PPMS is more difficult to diagnose and treat than types that remit and relapse.

Also, people with PPMS usually develop symptoms about 10 years later than those with relapsing types of MS.

Another key difference is that relapsing types affect two to three times more women than men. PPMS, on the other hand, develops among both sexes equally.

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Fatigue is sometimes a symptom of MS.

PPMS symptoms can affect a person’s everyday life and ability to complete regular tasks. Problems with mobility are characteristic of PPMS, usually due to spinal cord damage.

A person with PPMS may also experience the following symptoms:

  • changes in mood
  • muscle weakness
  • numbness
  • a tingling sensation
  • unclear or muddled thought
  • fatigue
  • balance problems
  • vision problems
  • problems with bowel and bladder control
  • sexual dysfunction
  • depression
  • paralysis

It is hard to predict which symptoms will develop in each person — no two people experience the same symptoms of MS.

Any type of MS can lead to many of these symptoms. Distinguishing PPMS from other types requires time and repeated diagnostic tests. A person must experience symptoms that consistently worsen over the course of 1 year for a doctor to diagnose PPMS.

In addition to having progressive symptoms, a person must exhibit at least two of the following criteria:

  • MS-related lesions in the brain that show on an MRI scan
  • two or more MS-related lesions on the spinal cord
  • elevated levels of immunoglobulin G antibodies or certain immune proteins in the spinal fluid

A doctor is likely to recommend regular MRI scans to track the disease’s progression.

One drug appears to slow the progression of PPMS. This is a disease-modifying therapy called ocrelizumab (OCR), or, by its brand name, Ocrevus.

In February 2016, the Food and Drug Administration (FDA) granted OCR “Breakthrough Therapy Designation” as a treatment for PPMS.

Guidelines from 2018 describe OCR as “the only [disease-modifying therapy] shown to alter disease progression in individuals with [PPMS] who are ambulatory.”

However, there is no evidence that OCR provides clinical benefit to people who are not mobile.

Here, learn important facts about multiple sclerosis.

Other measures

A range of therapies and strategies can help with managing symptoms and enhancing the quality of life.

Examples include:

  • Medications to help relieve symptoms: These can reduce, for example, depression, muscle spasms, and bladder problems.
  • Therapies: Physical, occupational, speech, and psychological therapies can help enhance strength, mood, and mobility, and some people feel that they promote independence.
  • Lifestyle adjustments: These should support physical and mental wellness. Examples include eating a healthful diet, exercising, meditating, and participating in counseling or group therapy.

It is also important for a person with any type of MS to avoid exposure to extreme temperatures. Being overheated can make symptoms worse.

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PPMS is an unpredictable type of MS.

PPMS is a highly unpredictable type of a disease that is already difficult to predict. Symptoms can be severe, and the rate at which they progress varies from person to person.

Authors of a study published in the Journal of Neurology, Neurosurgery & Psychiatry note that PPMS progression may depend on the types of symptoms and the age at which they first occurred.

To gauge the extent of disability from MS, a doctor may use the Kurtzke Expanded Disability Status Scale. The scores range from 0.0, demonstrating that a person has no symptoms, to 10.0, indicating that the presentation of MS may be fatal.

Some of the key functional differences on the scale include:

  • 4.0: A person is able to walk without an assistive aid, such as a cane. They are able to stand or walk around for at least 12 hours a day without overly reduced function.
  • 5.0: A person is able to walk without an aid for about 200 meters. However, the level of disability is severe enough to limit some daily activities, such as full-time work.
  • 6.0: A person needs occasional or daily assistance and uses a cane, crutch, or brace to walk distances of 100 meters or more.
  • 7.0: A person is unable to walk for 5 meters with an aid and usually uses a wheelchair.
  • 8.0: A person generally cannot move from a bed or chair and may use a motorized wheelchair. At this phase, a person’s arms are usually unaffected.

The transition between a score of 4.0 and 5.0 usually represents a change in a person’s ability to walk, which is a primary symptom of PPMS.

The authors of the study in the Journal of Neurology, Neurosurgery & Psychiatry report that the average time that it takes for a person with a diagnosis of PPMS to reach a score of 4.0 is 8.1 years.

The time that it takes to reach 8.0 can vary, but on average, this takes about 20.7 years, the authors found. The speed at which symptoms progress is faster in people with PPMS than in those with a relapsing type of MS.

As scientific advances lead to new medications, there is hope that the outlook for people with PPMS will improve.


Does PPMS always result in disability?


PPMS frequently is associated with weakness in the legs and difficulty walking. In one study, over 90% of patients with PPMS had weakness in the legs.

Seunggu Han, MD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.