Multiple sclerosis (MS) is a chronic autoimmune disorder that affects the optic nerves, spinal cord, and brain.

People who are diagnosed with MS often have very different experiences. This is especially true for those diagnosed with primary progressive multiple sclerosis (PPMS), one of the rarer types of MS.

The four types of MS are:

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

The types, or courses, have been identified based on how MS affects the body over time.

Each type has different treatment recommendations. The severity of their symptoms, and their outlooks, will also vary.

CIS is a newly defined type of MS. It occurs when you have a single episode of neurologic symptoms that last for at least 24 hours.

People who were previously diagnosed with progressive-relapsing MS (PRMS) are now considered primary progressive: active or not active.

PPMS is a unique type of MS. It involves less inflammation than relapsing forms of MS.

The main symptoms are caused by nerve damage. These symptoms occur because nerves aren’t able to send and receive messages to each other properly.

Those with PPMS have more plaques in the spinal cord than in the brain, as opposed to those with other types of MS.

PPMS isn’t very common. It only affects about 15 percent of those diagnosed with MS. As the name implies, the condition progresses from the time the primary, or first, symptoms are observed.

While other types of MS have periods of acute relapses and remissions, PPMS slowly but steadily gets worse with time. However, people with PPMS can occasionally have relapses.

PPMS also leads to a faster decline in neurological function than other MS types. However, the severity of the disability and how fast it develops depends on each case.

Some people may have continued disability that gets worse. Others may have steady periods without symptom flare-ups, or even periods of small improvements.

While other types of MS typically get diagnosed when people are in their 20s, PPMS is usually diagnosed when people are in their 30s and 40s. PPMS typically affects men and older women, unlike RRMS, which affects mostly younger women.

Common early symptoms of PPMS include weakness in the legs and problems with walking. These symptoms typically get worse over a period of two years.

PPMS affects people differently, but other symptoms typical of the condition include:

  • stiffness in the legs
  • problems with balance
  • memory problems
  • pain
  • weakness and tiredness
  • trouble with vision
  • bladder or bowel dysfunction
  • depression
  • fatigue
  • numbness and/or tingling in different parts of the body

The exact cause of PPMS, or MS in general, isn’t known. The most common theory is that MS begins as an inflammatory process of the autoimmune system, which results in loss of myelin. Myelin is the protective covering that surrounds nerves in the central nervous system (CNS).

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

While doctors don’t believe that PPMS can be inherited, it may have a genetic predisposition. Some believe that it may be triggered by a virus or by a toxin in the environment.

Four modifiers are used to characterize PPMS over time:

  • Active with progression: PPMS with worsening symptoms and relapses or with new MRI activity; increasing disability will also occur
  • Active without progression: PPMS with relapses or MRI activity, but no increasing disability
  • Not active with progression: PPMS with no relapses or MRI activity, but with increasing disability
  • Not active without progression: PPMS with no relapses, MRI activity, or increasing disability

A key characteristic of PPMS is the lack of remissions.

Even if a person with PPMS sees their symptoms stall (i.e., they don’t experience worsening disease activity or an increase in disability), their symptoms never actually improve. They’ll never regain any function they might have lost.

It’s important to work with your doctor to pinpoint which of the four types of MS you may have. This is because each type has a different outlook and different courses of treatment. There’s no specific test that can provide a PPMS diagnosis.

Doctors often have a harder time diagnosing PPMS in comparison to other types of MS and other progressive conditions. A neurological issue needs to have progressed for one or two years in order for someone to receive a PPMS diagnosis.

Other diseases that have symptoms similar to PPMS include:

  • an inherited condition that causes stiff, weak legs
  • a vitamin B-12 deficiency that causes similar symptoms
  • Lyme disease
  • viral infections, such as human T-cell leukemia virus type 1 (HTLV-1)
  • forms of arthritis, such as spinal arthritis
  • a tumor near the spinal cord

To diagnose PPMS, your doctor may:

  • evaluate your symptoms
  • review your neurological history
  • conduct a physical examination focusing on your muscles and nerves
  • conduct an MRI scan of your brain and spinal cord
  • perform a lumbar puncture to check for signs of MS in the spinal fluid
  • conduct evoked potentials (EP) tests to identify the specific type of MS; EP tests stimulate sensory nerve pathways to determine electrical activity of the brain

Ocrelizumab (Ocrevus) is the only drug approved by the Food and Drug Administration (FDA) to treat PPMS. It reduces nerve degeneration.

However, there are many treatments that may help with the progression of PPMS symptoms. These immunosuppressive therapies include:

  • azathioprine (Imuran)
  • cladribine (Cladibrine)
  • cyclophosphamide
  • methotrexate (Trexall)

Some medications are used to treat specific symptoms of PPMS, such as muscle tightness, pain, fatigue, and bladder and bowel problems.

There are a variety of disease-modifying therapies (DMTs) and steroids approved by the FDA for relapsing forms of MS. These medications aren’t usually helpful in treating PPMS. They target inflammation that occurs in the CNS and acute relapses, which aren’t typical of PPMS.

People with PPMS may be able to relieve symptoms with exercise and stretching. This can preserve mobility, control weight gain, and increase energy levels. Eating a healthy and nutritious diet and staying on a regular sleep schedule are also beneficial.

Physical and occupational therapy can also teach strategies for increasing mobility and managing symptoms, leading to improved quality of life.