In 2013, medical experts redefined the types of MS. As a result, PRMS is no longer considered one of the distinct types of MS.

People who might have received a diagnosis of PRMS in the past are now considered to have primary progressive MS with active disease.

Primary progressive multiple sclerosis (PPMS) is known for symptoms that worsen over time. The disease may be characterized as “active” or “not active.” PPMS is considered active if there are new symptoms or changes on an MRI scan.

The most common PPMS symptoms lead to changes in mobility, and they can include:

  • changes in gait
  • stiff arms and legs
  • heavy legs
  • an inability to walk for long distances

Progressive-relapsing multiple sclerosis (PRMS) refers to PPMS with active disease. A small percentage of people with multiple sclerosis (MS) have this progressive-relapsing version of the disease.

At the onset of MS, some people go through fluctuations in symptoms. Sometimes they don’t show any signs of MS for days or weeks at a time.

However, during dormant periods, symptoms can appear without warning. This may be called an MS relapse, exacerbation, or attack. A relapse is a new symptom, recurrence of an old symptom that had previously gotten better, or worsening of an old symptom that lasts more than 24 hours.

Relapses in active PPMS are different from relapses in relapsing-remitting multiple sclerosis (RRMS).

People with PPMS experience a gradual procession of symptoms. Symptoms may get a little better but never completely go away. Because the symptoms of a relapse never go away in PPMS, a person with PPMS will often have more MS symptoms than someone with RRMS.

Once active PPMS develops, relapses can occur spontaneously, with or without treatment.

Mobility symptoms are among the most common signs of PPMS, but the severity and types of symptoms can vary from person to person. Other common signs of active PPMS can include:

As the disease progresses, PPMS can cause less common symptoms such as:

  • changes in speech
  • tremors
  • hearing loss

Aside from relapses, active PPMS is also marked by a consistent progression of decreased neurological function.

Doctors can’t predict the exact rate of PPMS progression. In many cases, the progression is a slow but steady process that spans several years. The worst cases of PPMS are marked by rapid progression.

PPMS can be difficult to diagnose at first. This is partially because relapses in PPMS aren’t as noticeable as they are in other less severe forms of MS.

Some people pass off the relapses as the result of having bad days rather than assume that they’re signs of disease exacerbations. PPMS is diagnosed with the help of:

Your treatment will focus on helping to manage relapses. The only FDA-approved medication for PPMS is ocrelizumab (Ocrevus).

Medications are just one aspect of MS treatment. Your doctor may also recommend lifestyle changes to help ease your symptoms and improve quality of life. Regular physical activity and nutrition can complement medical care for MS.

There’s currently no cure for MS.

Like other forms of the disease, treatments may help slow the progression of PPMS. Treatment can also alleviate symptoms.

Early medical intervention can help prevent the disease from significantly affecting your quality of life. However, it’s important to get a proper diagnosis from your doctor to make sure you receive adequate care.

Researchers continue to study MS to understand the nature of the disease and possibly look for cures.

PPMS clinical studies are less prevalent than other forms of the disease because it isn’t as easy to detect. The recruiting process for clinical trials can be difficult given the rarity of this type of MS.

Most trials for PPMS study medications to manage symptoms. If you’re interested in participating in a clinical trial, discuss the details with your doctor.