Multiple sclerosis is a chronic autoimmune condition that impacts the central nervous system, including the brain and spinal cord. It affects nearly one million people in the United States and more than 2.3 million people worldwide. MS is a progressive disease, meaning it can get worse over time without treatment. However, treatment can’t always slow the progression of the disease. There are four types of multiple sclerosis: clinically isolated syndrome, relapsing-remitting MS, primary progressive MS, and secondary progressive MS.
Common symptoms of MS that can occur at any stage include numbness and tingling, muscle spasms, loss of balance, and spasticity. Other symptoms that can occur with the condition include fatigue, cognitive changes, and weakness.
Multiple sclerosis is a complex and unpredictable disease. Because there is no way to know for certain how someone’s MS will progress, there is no set timeline for how long it will take to move from one stage to the next.
Clinically Isolated Syndrome
Clinically isolated syndrome (CIS) is one type of multiple sclerosis. With CIS, the first episode of neurologic symptoms lasts at least 24 hours. These include:- Numbness or tingling
- Dizziness and shakiness
- Muscle stiffness
- Paralysis
- Vision changes, such as double vision
- Bladder or bowel dysfunction
- Age
- Ethnicity
- CIS symptoms
- Number, location and size of lesions
- Vitamin D levels
Relapsing-remitting Multiple Sclerosis (RRMS)
Relapsing-remitting multiple sclerosis is the most common type of MS. About 85% of MS patients have RRMS. It’s defined by inflammatory attacks on myelin and nerve fibers. The exact cause of RRMS is currently unknown, but experts believe a combination of genetic and environmental factors may play a role in the development of RRMS and other forms of MS. With RRMS, patients have relapses that last 24 hours or longer followed by periods of stability. During a relapse, you may have symptoms you’ve experienced before or new ones. Past symptoms may appear in different parts of the body than you’re used to. Every relapse is different. It isn’t possible to know when they will happen or how often. People with RRMS usually have one or two relapses a year. The symptoms of a relapse usually come on suddenly. A relapse can range from mild to severe and can last anywhere from a few hours to a few months. Most relapses can be self-managed at home, but some may need hospital treatment. A relapse is followed by a remission or period of recovery. During remission, symptoms may disappear completely while others may continue and become permanent. There is no obvious progression of MS during a relapse. RRMS can be classified with four modifiers:- Active—Relapses or lesions are found on an MRI
- Not active—No relapses or MRI activity
- Worsening—Symptoms get progressively more severe after a relapse
- Not worsening—Symptoms do not get progressively more severe after a relapse
- Vision loss or double vision
- Fatigue
- Tingling or numbness
- Balance problems
- Weakness
- Sensitivity to heat
- Dizziness
- Trouble thinking clearly
- Depression
Benign MS
Benign MS is the mildest type of multiple sclerosis. It is often considered a variation of RRMS. It can appear as an extended period of remission with few or no symptoms. About 10% of people with MS have a benign disease course. Neurologists may use the Expanded Disability Status Scale (EDSS) to recognize benign MS. The EDSS measures the extent of physical impairment and ranges from 0 to 10. The standard criterion for benign MS is below 3 on the EDSS. This means there is no evidence of worsening body functions and no increase in disease activity. People with MS receive a diagnosis of benign MS 15 years or more after the initial MS diagnosis. Long-term follow-up of people with benign MS shows that some who didn’t take MS medications eventually became disabled.Primary Progressive MS (PPMS)
Primary progressive MS (PPMS) is a severe type of multiple sclerosis. It's characterized by worsening neurologic function from the onset of symptoms without early relapses or remissions. There are four forms of PPMS:- Active PPMS with progression—Worsening symptoms and relapses, or new MRI activity. Increased disability.
- Active PPMS without progression—Relapses or MRI activity, but no increasing disability.
- Not active with progression— No relapses or MRI activity, with increasing disability.
- Not active without progression—No relapses, MRI activity, or increasing disability.
- Weak, stiff legs
- Trouble with balance
- Trouble walking
- Pain (headaches, muscle spasms)
- Dizziness or shakiness
- Vision changes
- Depression
- Fatigue
- Bladder or bowel dysfunction
Secondary Progressive MS (SPMS)
Secondary progressive MS is a type of multiple sclerosis that develops from RRMS. Most patients with RRMS will eventually develop SPMS. Studies have shown that 50% of people diagnosed with RRMS will transition to SPMS within 10 years. Ninety percent will transition to SPMS within 25 years. The transition from relapsing-remitting MS to progressive MS is gradual. It is possible to be diagnosed with SPMS from the beginning, as mild relapses early can be overlooked. Like other types of multiple sclerosis, there is no single test to diagnose SPMS. Once there is a diagnosis of RRMS, your doctor will continue to observe your symptoms over a period of time to determine if they have progressed to SPMS. It is not clear why people progress from RRMS to SPMS and others don’t. Some researchers believe it is because of a nerve injury that happened early in the disease. This injury may cause the nerve fibers to disappear, triggering the progression of RRMS to SPMS. While it is possible to delay disease progression, it cannot be stopped completely. Disease-modifying therapies can help decrease inflammation, which reduces the severity and frequency of MS attacks. Other medications may address specific symptoms such as depression or muscle spasms. People with SPMS can continue to take the same drugs they took with RRMS if they helped. Medications for active SPMS include cladribine and mitoxantrone. Most patients with SPMS have fewer relapses than they would have with RRMS since there is less inflammation. However, the symptoms steadily worsen over time. Unlike RRMS, remissions in SPMS are incomplete and symptoms often remain present. Like RRMS and PPMS, secondary progressive MS can be categorized with modifiers like active and not active, and with progression or without progression.- Active SPMS—Relapses and/or new MRI activity
- Not active SPMS—No relapses or new MRI activity
- With progression—Evidence of increasing disability over time, with or without relapses or new MRI activity
- Without progression—No evidence of increasing disability
- Trouble walking
- Poor balance or coordination
- Bladder or bowel dysfunction
- Sexual difficulties
- Spasticity
- Numbness or tingling