What Are the 4 Types of MS?
Nearly 1 million people in the United States are living with multiple sclerosis (MS), according to a study funded by the National Multiple Sclerosis Society (NMSS). And while many people have the disease, they each can experience it very differently.
Although it can be difficult to predict exactly how the disease will affect you, it can be helpful to understand the basics of multiple sclerosis and the four common MS types, or subsets, to get a sense of what’s happening and how it may affect you.
Research into multiple sclerosis has yet to establish the cause of the disease. It’s most often diagnosed in adults between ages 20 and 50. The NMSS also states that women are three times more likely to get it than men, which may be due in part to hormones.
MS is an immune-mediated disorder in which the body's immune system mistakenly attacks the central nervous system (CNS), including the brain, spinal cord, and optic nerves (the connection between the back of the eye and the brain). It can be characterized by short episodes of neurological symptoms (also known as relapses), progressive damage to the CNS, or both.
“An episode is defined as either the appearance of new neurologic symptoms or perhaps a return of previously resolved neurologic symptoms that has to last at least 24 to 48 hours and is not due to an identifiable cause such as an infection or overheating,” says Barbara Giesser, M.D., a board-certified neurologist and MS specialist at Pacific Neuroscience Institute at Providence Saint John’s Health Center, in Santa Monica, California.
Symptoms of MS can include fatigue, vision problems, bladder issues, and transverse myelitis, an inflammation in the spinal cord that can cause numbness and weakness in the arms and legs or difficulty walking. The symptoms may last for days or weeks, and then can subside either partially or fully for a period of time.
4 Types of MS
The course of MS—how the disease presents itself—will be unique to each person, and each individual can have variable symptoms over time. The severity of the disease can also be quite different. “There are four types of MS, which are based on their clinical course,” says Cori Cummings, M.D., a board-certified neurology resident at the Medical University of South Carolina, in Charleston.
Each course of multiple sclerosis has its own impact on a person’s quality of life. Here are the four main types of MS:
1. Clinically Isolated Syndrome (CIS)
CIS is when a person has a first-time bout of symptoms, but they haven’t yet experienced another episode. This could be the first sign of MS, or there could be another explanation. “That initial attack may be optic neuritis, or they could have an inflammatory attack to their spinal cord,” says Kalina Sanders, M.D., a board-certified neurologist at Baptist Neurology Group, in Jacksonville Beach, Florida.
About half of people with CIS will go on to develop the second type of MS: relapsing-remitting multiple sclerosis (RRMS). Doctors will likely order an MRI (magnetic resonance imaging) to look for lesions on the brain. If they see markers for MS, the person is likely to have a second episode, meaning they will develop RRMS.
2. Relapsing-Remitting MS (RRMS)
By far the most common MS subtype, RRMS affects about 85% of people diagnosed with MS. It’s characterized by an attack of symptoms (relapse), followed by a period of remission (relative improvement in symptoms), which may last for months or even longer.
“During remission, a person doesn't get completely back to their baseline; there are usually a few persistent symptoms afterward,” Cummings notes. During RRMS, there’s not a discernible progression of the disease, just the cycle of relapse and remission.
3. Secondary Progressive MS (SPMS)
Before disease-modifying treatments were developed, studies showed that in several years or decades, about 50% of the people diagnosed with RRMS would go on to have a different form of MS: secondary progressive. It’s not entirely known how these medications can alter the transition from RRMS to SPMS, but most neurologists believe that the treatments do have some positive impact on disease progression from the former type of MS to the latter.
“People with SPMS have a slow accumulation of disability without significant relapses or MRI changes,” Sanders says. That means they may stop experiencing episodes of symptoms but have slowly worsening weakness or numbness to the point that it becomes difficult to walk.
4. Primary Progressive MS (PPMS)
As the name implies, people with PPMS experience a steady disease progression. But it starts out differently than SPMS does. “The big distinction is that with primary progressive MS, a person never starts out with relapsing-remitting at onset,” Cummings says. This type of multiple sclerosis affects about 15% of people with the disease. “It's a harder one to diagnose because people don't have distinct flares,” she adds.
All forms of MS are generally diagnosed by a neurologist. Doctors identify the disease through clinical diagnosis of symptoms and radiologic evidence. Although there isn’t a specific test that can identify any given type of MS, doctors do follow certain guidelines.
“The guidelines include that you have to be able to demonstrate that there's damage in different parts of the central nervous system,” Giesser says. “We get that evidence, in large part, by looking at an MRI.” It’s also important to rule out other diseases that might share similar symptoms or MRI findings.
In the past, multiple sclerosis was considered a debilitating diagnosis, but treatment advances have significantly changed the landscape of life with the condition. “It isn't really something we think of as a life-shortening diagnosis now,” Cummings says. The sooner a person is diagnosed, the sooner they can start treatment, which can help delay progression of the disease.
Treatment and Management
Once a person is diagnosed, a doctor will likely prescribe them treatment, along with lifestyle recommendations and ways to manage the symptoms they’re experiencing.
There are 23 FDA-approved disease-modifying drugs for MS, and there are a couple used off-label as well. “These are not cures, and they're not medications that reverse any preexisting damage,” Giesser says. “But what they do is they decrease the number and severity of exacerbations, and they decrease new areas of nerve damage.”
There are three different classes of these therapies: injectable, oral, and infused medications. Most of these drugs were developed to treat RRMS, since it's the most common form, but there are options for the other types of MS as well.
Medications such as steroids can be used to treat symptoms during flares, too. And doctors emphasize the importance of healthy lifestyle habits to help quality of life with MS.
"A healthy lifestyle includes eating an anti-inflammatory diet and avoiding smoking," Sanders says. An anti-inflammatory diet includes plenty of fruits and vegetables, healthy fats such as olive oil and nuts, and lean proteins like salmon. In addition, a doctor may refer a patient for rehabilitation to improve functioning and range of motion. This might include occupational or physical therapy.
While it can be daunting to receive a diagnosis of MS, it’s good to remember that treatment for it has come a long way. “It's not the same disease it was years ago,” Cummings says. “We have really good therapies, and we’re catching it much earlier. So, I think it's honestly really encouraging.”
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