What Are the Symptoms of Primary Progressive Multiple Sclerosis?

Difficulty Walking and Other Spinal Cord-Related Problems in PPMS

Man suffering from Parkinson's disease and multiple sclerosis standing near steps
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Primary progressive MS affects approximately 10 to 15 percent of people with MS and is diagnosed equally in men and women. In primary progressive MS (PPMS), a person does not have typical flares or relapses. Instead, their symptoms usually arise gradually and are not reversible, which means that a person does not return to their baseline neurological function.

Like other forms of MS, PPMS is variable, affecting each person differently -- some may become disabled within a few years whereas others remain stable for decades.

That being said, people with PPMS tend to require more help with everyday functioning, as compared to those with relapsing remitting MS.

The vast majority of patients who end up diagnosed with primary progressive multiple sclerosis (PPMS) begin noticing problems walking.

Worsening Ability to Walk (Spinal Cord Syndrome) in PPMS

Walking disturbances and other spinal-cord related problems are by far the most common symptoms of PPMS, affecting as many as 80 to 85 percent of patients. Also called progressive myelopathy, these symptoms consist of:

  • An increasingly spastic gait (called spastic paraparesis), with the legs stiffening up to cause a limp and/or rhythmic jerkiness
  • Spastic hemiparesis, where there is weakness or inability to move on one side of the body (arms or legs) and/or an inability to hold things on that side
  • Clumsiness, stiffness, dragging legs
  • Exercise-related fatigue, meaning people are not able to walk far without resting
  • Stumbling and falling

Due to the fact that the spinal cord is affected, other common symptoms include problems with sexual, bladder, and bowel function. Fatigue is also a common symptom in PPMS, as in other types of MS.

In patients that have these types of symptoms, the MRI scans of their brains show few (if any) lesions and few gadolinium-enhancing lesions.

However, an MRI scan of their spines will often show atrophy, which is a result of axon and oligodendrocyte cell loss and injury.

Tremor and Imbalance (Progressive Cerebellar Syndrome) in PPMS

While walking and other spinal cord-related issues are common in PPMS, for some, the first symptoms  are slowly worsening tremor and problems with balance.

A small minority (up to 10 percent) of people with PPMS have these types of symptoms, which are characterized by:

  • Severe intention tremor, the inability to perform small movements accurately due to shaking or trembling hands
  • Hypotonia, a loss of muscle tone
  • Problems with balance
  • Incoordination
  • Dysmetria, the lack of ability to coordinate movements, which is exhibited by the person “overshooting” (hypermetria) or “undershooting” (hypometria) the intended position of the hand, arm or leg
  • Dysdiadochokinesia, which is the inability to perform rapid, alternating movements
  • Gait ataxia, a staggering way of walking

People with these symptoms are more likely to have abnormal brain MRI scans than people with spinal cord syndrome.

These brain MRIs resemble those of people with secondary progressive multiple sclerosis (SPMS) or people that have had relapsing remitting multiple sclerosis (RRMS) for a long time.

Likewise, the cause of progressive cerebellar syndrome is probably more inflammatory (meaning an immune system attack on myelin) like in SPMS and RRMS.

On the flip side, the cause of PPMS in people who have spinal cord syndrome is believed to be less inflammatory and more of a degenerative process in which nerve fibers (called axons) are gradually destroyed. This is why treatment of patients with PPMS can be tricky, as disease-modifying therapies target inflammation.

Other Possible Symptoms of PPMS

While much less common, the following symptoms can also be signs of PPMS:

  • Brainstem Syndrome: 1 percent of people with PPMS initially experience difficulties with swallowing, hoarseness, dizziness, nausea and vomiting, rapid involuntary movements of the eyes ( called nystagmus).
  • Vision Impairment or Loss: 1 percent of people with PPMS experience progressively worsening vision.
  • Cognitive Problems: 1 percent of people with PPMS have initial cognitive dysfunction symptoms, which includes problems with attention span, verbal memory, verbal fluency, and spatial reasoning.

Bottom Line

While there are currently no FDA-approved medications for treating PPMS, the good news is that there are excellent therapies to help manage symptoms, like physical and occupational therapy to optimize mobility and independence. Also, some neurologists will try a disease-modifying therapy in patients with PPMS -- for some it may work, especially if the diagnosis of PPMS is not clear-cut.


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National MS Society. Frequently Asked Questions about PPMS

Thompson, A. (2004). Overview of primary progressive multiple sclerosis (PPMS): similarities and differences from other forms of MS, diagnostic criteria, pros and cons of progressive diagnosis. Multiple Sclerosis,10: S2-S7.

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