What Is Multiple Sclerosis? Symptoms, Causes, Diagnosis, Treatment, and Prevention
Multiple sclerosis, or MS, is a disease of the central nervous system that can cause symptoms throughout the body.
The term “multiple sclerosis” refers to the multiple areas of scar tissue — often called “lesions” — that develop along nerve fibers in the brain, spinal cord, and optic nerve and that are visible in MRI scans. The literal meaning of “sclerosis” is “pathological hardening of tissue.”
Most experts believe MS is an autoimmune condition, in which the immune system mistakenly attacks normal tissues in the body.
In the case of MS, the immune system attacks the myelin sheath that normally protects nerve fibers in the central nervous system. The underlying nerve fibers can also be damaged or destroyed in this attack.
As the attack progresses, the myelin sheath becomes inflamed and gradually is destroyed, leaving areas of sclerosis that disrupt the electrical impulses between the brain and other parts of the body, leading to MS symptoms.
Advances in imaging technologies and further research are needed to clarify what actually causes MS and how best to treat it.
Common Questions & Answers
Race to Erase MS 2022
Types of Multiple Sclerosis
Scientists have long described different types of MS, the most common being relapsing-remitting MS, primary-progressive MS, and secondary-progressive MS.
Nonetheless, most people with MS are still diagnosed with a particular type of the disease based on their progression of symptoms.
Relapsing-Remitting MS (RRMS)
This type of MS is characterized by periods of active inflammation in the central nervous system, during which symptoms worsen (and new symptoms may develop), alternating with periods when symptoms are less acute.
The times when symptoms worsen are known as relapses, flares, or exacerbations. As a relapse ends, the severity of symptoms diminishes, but a person can be left with new, permanent symptoms.
The quiet periods between relapses are called remissions. Remissions may last for months or years before a relapse occurs.
RRMS is the most common type of MS — estimates vary, but between 80 and 90 percent of people with MS are diagnosed with this relapsing-remitting course of the disease, and most people with RRMS eventually develop secondary-progressive MS.
Secondary-Progressive MS (SPMS)
This type of MS is generally considered a second phase of RRMS, in which there is symptom progression and increased disability. People with SPMS may continue to have relapses, although they may be less frequent than in RRMS.
Most people who are diagnosed with RRMS will eventually transition to SPMS, but each person’s experience with it — whether or not they have relapses and how much progression, or disease worsening, occurs — will be unique.
Learn More About Secondary-Progressive MS
Primary-Progressive MS (PPMS)
In PPMS there is no initial relapse that signals the beginning of the disease. Instead, MS symptoms gradually appear over time.
Those who have PPMS generally do not experience acute exacerbations or have distinct remissions, but they may have temporary plateaus during which symptoms lessen somewhat.
Learn More About Primary-Progressive MS
A small percentage of people with MS have a benign form of the disease, in which symptoms progress very little over the course of a person's lifetime, after the initial attack.
There’s some controversy over how (or whether) to classify people with benign MS, since the progress of the disease can vary over a person’s lifetime, according to the NMSS.
Signs and Symptoms of Multiple Sclerosis
The nerve damage that occurs in MS can lead to a broad range of symptoms, depending on what part of the central nervous system has been attacked. MS can affect numerous areas of the brain, as well as the optic nerve — the nerve that transmits signals from the eye to the brain — and the spinal cord.
It’s often said that no two people with MS have exactly the same pattern of symptoms. In addition, an individual’s symptoms can change or fluctuate in severity over time.
Some common early symptoms of MS include visual problems, difficulties with balance and walking, numbness and tingling, and heat intolerance.
Other common symptoms include:
- Bladder and bowel dysfunction
- Muscle spasticity
- Problems with thinking and memory
- Sexual dysfunction
- Sleep problems
Less-common symptoms of multiple sclerosis include:
- Breathing problems
- Difficulty moving arms
- Difficulty reading facial expressions
- Diminished fine motor control in hands
- Diminished sense of taste or smell
- Hearing loss
- Hypersensitivity to touch
- Itchy skin or altered sensations
- Lhermitte’s sign
- “MS hug”
- Pseudobulbar affect
- Sensitivity to cold
- Speaking problems
- Swallowing problems
- Trigeminal neuralgia
In many cases, MS symptoms can be treated, sometimes with medication and sometimes with a form of rehabilitation, such as physical therapy, occupational therapy, speech therapy, or cognitive therapy. People with MS who are depressed can often be helped by the same types of antidepressants, psychotherapy, and lifestyle changes that are beneficial for depressed people who don’t have MS.
Even when treatment can’t alleviate an MS symptom entirely, it can often reduce its severity.
What Is a Multiple Sclerosis Relapse?
A relapse, or flare, is a worsening of existing MS symptoms — physical and cognitive — often accompanied by the appearance of new symptoms. Relapses occur because of inflammation of previously existing lesions, new areas of inflammation in the central nervous system, or both.
Typically, relapses come on over hours or days and can last for days or weeks.
A true relapse occurs at least 30 days after your most recent relapse and lasts for at least 24 hours. Shorter periods of symptom worsening, called pseudoexacerbations, can be triggered by heat, stress, and fatigue, among other things. Once the underlying cause of a pseudoexacerbation is reduced or eliminated, the MS symptoms should abate too.
Treatment for a relapse often includes a short course of high-dose steroids, such as Solu-Medrol (methylprednisolone), delivered intravenously in an outpatient clinic or infusion center. Steroids speed recovery but cannot repair any new damage to the nervous system caused by the inflammation.
How Much Do You Know About MS Symptoms?
Causes and Risk Factors of Multiple Sclerosis
The cause of MS is unknown — no one knows what sets off the disease process that leads to MS lesions in the first place. But it is thought that some combination of genetic susceptibility and environmental causes is necessary to trigger the disease.
Approximately 20 percent of people with MS have a family member who has it, but even having an identical twin with MS increases the risk by only 20 to 40 percent. So even though having a family history of MS raises the risk somewhat, MS is not considered a genetic or hereditary disease.
Learn More About Causes of Multiple Sclerosis: Common Risk Factors, Genetics, and More
How Is Multiple Sclerosis Diagnosed?
MS is generally diagnosed on the basis of a person’s history of symptoms, along with the results of a variety of medical tests, which may include:
- A neurological evaluation of physical movement and coordination, vision, balance, and mental functioning
- Blood tests to rule out other conditions
- Magnetic resonance imaging (MRI) scans to detect brain lesions typical of MS
- Lumbar puncture (spinal tap) to obtain cerebrospinal fluid, which may contain substances more likely to be found in people with MS
Diagnosing MS early is critical so that treatment can begin early, with the goal of reducing the number of relapses a person experiences and slowing the progression of the disease.
But no single test can definitively diagnose the disease, and MS symptoms mimic those of a number of other conditions.
In addition, symptoms of MS and their severity vary widely from person to person. Symptoms can also come and go from one day or week to the next, as well as change gradually over time.
All this makes diagnosing MS a challenge, even with a newly revised set of guidelines known as the McDonald criteria, which spell out what’s needed to accurately diagnose MS.
Prognosis of Multiple Sclerosis
Although MS can sometimes be a debilitating disease, the majority of people who have it don't become severely disabled, according to the National MS Society.
Many people with MS are able to maintain their mobility with the help of assistive devices, such as canes or crutches, often supplemented with scooters or motorized wheelchairs for long distances. About one-third of people with MS completely lose their ability to walk.
People with MS who have the best prognosis are usually those who:
- Are female
- Were younger than 30 when the disease started
- Have infrequent attacks
- Have relapsing-remitting MS (RRMS)
- Have few signs of disease in diagnostic scans
The researchers found that brain and spinal cord MRIs done soon after clinically isolated syndrome (CIS), or a single episode of demyelination, predicted disease progression 15 years later. CIS sometimes, but not always, develops into MS. In the 166 study participants who were assessed after 15 years, certain types of lesions — specifically spinal cord and gadolinium-enhancing lesions — on their initial MRIs were linked to development of secondary-progressive MS at follow-up.
Duration of Multiple Sclerosis
- Aspiration pneumonia
- Respiratory infection
- Respiratory disease
- Urinary tract infection
- Other infection, including sepsis
- Skin disease, typically pressure ulcers
Of course, people with MS also die from the same systemic illnesses that kill people in the general population, such as heart disease and cancer, underscoring the importance of maintaining the type of healthy lifestyle habits that can lower the risk of these diseases.
Treatment and Medication Options for Multiple Sclerosis
Treatment for MS often includes disease-modifying medication to reduce the number and severity of relapses in those who have them and to slow disease progression. But these drugs don’t treat MS symptoms, nor are they effective at shortening an MS relapse that’s in progress.
For this reason, treating MS generally involves a multipronged approach, including:
- High doses of steroids or sometimes plasmapheresis to shorten relapses
- Disease-modifying therapies to prevent relapses and disease progression
- Treating the symptoms of MS using medication, physical therapy, other types of rehabilitative therapies, a healthy lifestyle, and complementary treatments
- Counseling and support for depression, anxiety, and other mood disorders
Disease-Modifying Therapy Options
For people who have relapsing-remitting MS, a long list of disease-modifying drugs are approved to lower the frequency and severity of acute attacks and slow disease progression.
For people with primary-progressive MS, only one medication, Ocrevus (ocrelizumab), has been shown to reduce the likelihood of disability progression.
And for people with “active” secondary-progressive MS, meaning they still experience relapses, and new lesions continue to be seen on their MRIs, a growing number of drug treatments have become available since 2019.
Learn More About Medication for Multiple Sclerosis
Treatments for MS Symptoms
Doctors can prescribe a wide variety of drugs to relieve symptoms related to MS, include analgesics for pain; antispasmodics, such as baclofen, and muscle relaxants, such as Zanaflex (tizanidine), to ease muscle spasticity; and Ampyra (dalfampridine) to improve walking ability.
Physical therapy can also be helpful for dealing with fatigue, weakness, pain, and spasticity. A physical therapist can prescribe exercises, stretches, and alternative ways of performing physical tasks to improve energy levels and physical functioning.
Occupational therapy is often used to find easier or alternative ways to achieve tasks of daily living, including by using assistive devices and energy conservation techniques.
Your doctor can also refer you for speech-language therapy to address problems with speaking or swallowing, cognitive rehabilitation for help with memory and thinking tasks, and psychotherapy for help with depression, anxiety, grief, or simply distress related to living with a chronic condition.
In addition to formal rehabilitation and therapy, exercise and meditation have both been shown to improve function and quality of life for people living with MS.
Learn More About Treatment for Multiple Sclerosis: Drug Therapy, Rehabilitation, Alternative and Complementary Therapies, and More
Prevention of Multiple Sclerosis
As of yet, there’s no surefire way to prevent multiple sclerosis, in large part because the cause of the disease is not yet fully understood. But there are some healthy behaviors that can reduce an individual’s risk of MS.
So while there’s no guarantee that upping your vitamin D levels will prevent MS, it’s also likely to do no harm, as long as you stay within safe limits of both sun exposure and vitamin D supplementation.
Complications of Multiple Sclerosis
Beyond the direct effects of MS symptoms — of which there are many and of varying severity — there can be additional consequences of some symptoms.
Urinary Tract Infections
Some people have trouble holding their urine in (incontinence), while others can't fully empty their bladder (retention).
Failing to empty the bladder completely raises the risk of developing a urinary tract infection (UTI), which can cause worsening MS symptoms, as well as discomfort when urinating, needing to urinate frequently, and releasing only small amounts of urine.
If not treated quickly, a urinary tract infection can in turn lead to a kidney infection, which is a medical emergency.
Sometimes people with MS have trouble swallowing, known as dysphagia. When the timing of a swallow is off, or the muscles involved in swallowing are weak, foods and liquids may enter the airway instead of the esophagus, where they belong.
If the person cannot cough forcefully enough to expel them, the food and liquid can end up in the lungs. This can lead to aspiration pneumonia, a serious condition that can require hospitalization.
Symptoms of aspiration pneumonia may include chest pain, fever, shortness of breath, and coughing up foul-smelling phlegm. You should seek medical help if you experience these symptoms.
Physical Trauma From Falling
Many MS symptoms, including balance problems, muscle weakness, fatigue, dizziness, blurred vision, and numbness, raise the risk of falling.
Falls, in turn, raise the risk of serious injuries, such as broken bones and head trauma. Falling can also lead to fear of falling, which typically causes a person to become less active, weaker, and even more prone to falling.
While not all falls can be prevented, many can, through a range of strategies to build leg strength, improve balance, fall-proof your home, and address potential causes of dizziness.
People with MS who spend most of their time sitting or lying down need to be aware of — and take steps to prevent — pressure sores. Also known as bedsores or pressure ulcers, pressure sores are areas of damaged skin caused by extended pressure to one area.
They tend to develop in areas where the bones are close to the skin, such as the heels, tailbone, shoulder blades, and elbows. A combination of moving more often, using special cushions or mattresses, and checking your skin every day can help prevent pressure sores or catch them early.
Risk of Depression Is High in Multiple Sclerosis
Depression is common among people who have MS, and not just because it’s stressful to have an unpredictable progressive disease.
Depression in MS may be a direct result of the immune system's attack on the protective myelin sheaths that envelop nerve fibers, causing behavioral changes, including depression.
Multiple sclerosis can also change what is known as the body's neuroendocrine system, which oversees hormone release, including hormones implicated in depression, such as serotonin.
Additionally, some medicines used to treat MS, such as interferon beta, can also cause depression.
And sometimes depression develops as a result of the stresses and challenges associated with having MS.
The good news: No matter what its underlying cause, depression in people with MS can be treated with psychotherapy, medication, or a combination of the two.
Research and Statistics: Who Has Multiple Sclerosis?
Going forward, more and better information about MS trends in America, including the number of new cases, should be available through the CDC’s National Neurological Conditions Surveillance System, which was established in 2016 and funded in 2019.
In the meantime, what is known now about MS is that while anyone can develop it, many of those who have it share the following characteristics:
Age The majority experience their first symptoms between the ages of 20 and 40.
Race White people have long been believed to be more than twice as likely as other races to develop MS. But the underrepresentation of racial and ethnic minorities in clinical trials calls this belief into question.
Climate MS is five times more common in temperate climates — like the northern United States, Canada, and Europe — than in tropical climates.
Genes People whose close relatives have MS are more susceptible to the disease, but there is no evidence the disease is directly inherited in most cases.
Black Americans and Multiple Sclerosis
It’s unknown exactly how common MS is among Black Americans, in part because researchers have only just begun to investigate this question, and in part because the complex causes of MS mean that the incidence of disease is likely to vary from one study population to another.
On the basis of his research, Bruce Cree, MD, PhD, a neurologist and the clinical research director at the multiple sclerosis center at the University of California in San Francisco, estimates that compared with people of Northern European ancestry in the United States, those of African ancestry develop MS at about half the rate. Yet Black Americans tend to develop more aggressive forms of MS than white Americans do, with a larger percentage having spinal lesions, indicating more aggressive disease.
As far as treatment for MS in Black Americans, studies have generally suggested that the MS treatments that work better for white people also work better for African Americans, although the evidence is limited.
The National MS Society encourages Black people with MS to check out several research initiatives in the United States that are seeking Black, and in some cases Hispanic or other ethnic minority, volunteers.
In the meantime, anyone, of any race or ethnicity, with symptoms that suggest MS should seek medical care for diagnosis and appropriate treatment.
Conditions Related to Multiple Sclerosis
A number of medical conditions occur at greater frequency in people with MS without necessarily being direct symptoms or complications of MS, although in many cases the link between the diseases remains unclear. Headache, migraine, fibromyalgia, and epilepsy are four such conditions.
Headache and Migraine
Headaches, and particularly migraine, are more common among people with MS than the general public, and the reasons for this are not fully understood. While some studies have found that the use of disease-modifying therapies to treat MS reduces the incidence and frequency of headache, others have found that certain MS therapies are linked to more headaches.
Fibromyalgia is sometimes mistaken for MS, and MS is sometimes mistaken for fibromyalgia. Both occur more frequently in women, and both can cause pain, fatigue, and brain fog, among other symptoms. Many people live with both conditions.
People with MS who have recurrent seizures are generally treated with anti-seizure medication.
Resources We Love
Favorite MS Patient Advocacy Orgs
National Multiple Sclerosis Society
The National MS Society is probably the best-known MS patient advocacy organization in the United States, and for good reason. It provides information, assistance, and support of various kinds through its local chapters and through its MS Navigators, who are available to chat online or by phone. It’s a great place to start if you have questions about MS, need help finding a healthcare provider or understanding health insurance benefits, want to attend a local MS-related event, or want to get involved in advocacy work yourself.
Multiple Sclerosis Association of America
The MSAA specializes in improving the lives of people living with MS through its toll-free helpline, cooling products program, MRI access fund, and much more. Check out its calendar of events for free educational presentations around the United States and Puerto Rico. Try out its My MS Manager app to track disease activity, store your medical information, and generate charts and reports. (The app is available for both Android and iOS devices and is free for individuals with MS and their caregivers.) MSAA has also teamed up with HealthUnlocked to provide a space for online discussion and support.
MS Focus offers a variety of grant programs to provide assistive technology, laptop computers, emergency living assistance, home care, and cooling items. The website also provides a directory of MS support groups and lists live events focused on MS education, fundraising, and wellness activities.
International Progressive MS Alliance
Progressive forms of MS, which include primary- and secondary-progressive MS, can cause significant physical and cognitive disability, and until recently, no drug treatments were available for these forms of MS. The Progressive MS Alliance is working to change the lives of people with progressive MS by conducting more and better studies to hasten the development of drug treatments and other therapies for those affected.
The MS Coalition brings together nine member organizations with a shared commitment to improving the lives of people with MS. It provides a quick way to find out which of these organizations might have programs that are helpful to you.
Influential MS Fundraiser
The Race to Erase MS annual gala attracts a who’s who of celebrities and a lot of money to fund research on MS treatments. And while the ticket price of the gala may be a bit steep for ordinary people, the MS Forum and Expo that happens the next day is free and open to the public, and offers access to some of the top MS researchers in the United States.
Basic Info to Learn From and Share With Others
When you’re first diagnosed with MS or want to help friends and family members understand the condition, the Mayo Clinic website is a great place to start. The site offers basic information on symptoms, diagnosis, and treatment, and simple illustrations of what’s happening in your body.
Favorite Videos Featuring MS Patients and Professionals
One way to feel less alone with MS is to listen to other people talk about their situation. The Consortium of Multiple Sclerosis Centers has put together a collection of videos featuring people living with MS as well as doctors, nurses, and other healthcare professionals who treat MS. Chances are you’ll find much to relate to, and maybe some new ideas on how to better manage MS.
Best Patient-Informed MS Research Org
Here’s a chance to participate in MS research without necessarily taking part in a clinical trial. When you join iConquerMS, you contribute information about your MS history, symptoms, and treatments. Researchers then use your information, along with that of thousands of other people living with MS, to look for patterns and clues about the causes of MS and the best ways to treat it. As an iConquerMS member, you can also make suggestions directly to researchers on the types of studies you’d like to see done.
Favorite Blog Collection
There are lots of great blogs out there by people with MS, but the advantage of subscribing to MultipleSclerosis.net is that you get regular blog posts from a whole bunch of diverse voices. Yes, they all share the diagnosis of multiple sclerosis, but they each have their own experiences, concerns, and perspective on life, MS, and the intersection of the two.
Favorite MS Podcast
Every week host Jon Strum tackles another MS topic, from stem cell transplants to advances in rehabilitation to healthcare legislation that could affect people with MS. Listen in as he interviews scientists, activists, MS caregivers, and others whose lives have been affect by MS.
Learn More About Additional Resources and Support for Multiple Sclerosis
Editorial Sources and Fact-Checking
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