Multiple sclerosis (MS) is a potentially disabling disease of the brain and spinal cord (central nervous system).
In MS, the immune system attacks the protective sheath (myelin) that covers nerve fibers and causes communication problems between your brain and the rest of your body. Eventually, the disease can cause the nerves themselves to deteriorate or become permanently damaged.
Signs and symptoms of MS vary widely and depend on the amount of nerve damage and which nerves are affected. Some people with severe MS may lose the ability to walk independently or at all, while others may experience long periods of remission without any new symptoms.
There's no cure for multiple sclerosis. However, treatments can help speed recovery from attacks, modify the course of the disease and manage symptoms.
- Myelin damage and the nervous system
Multiple sclerosis signs and symptoms may differ greatly from person to person and over the course of the disease depending on the location of affected nerve fibers. They may include:
- Numbness or weakness in one or more limbs that typically occurs on one side of your body at a time, or the legs and trunk
- Partial or complete loss of vision, usually in one eye at a time, often with pain during eye movement
- Prolonged double vision
- Tingling or pain in parts of your body
- Electric-shock sensations that occur with certain neck movements, especially bending the neck forward (Lhermitte sign)
- Tremor, lack of coordination or unsteady gait
- Slurred speech
- Problems with bowel and bladder function
Types of MS
MS starts in one of two general ways: with individual relapses (attacks or exacerbations) or with gradual progression.
More than 8 out of every 10 people with MS are diagnosed with the "relapsing remitting" type. Someone with relapsing remitting MS will have episodes of new or worsening symptoms, known as "relapses". These typically worsen over a few days, last for days to weeks to months, then slowly improve over a similar time period.
Relapses often occur without warning, but are sometimes associated with a period of illness or stress. The symptoms of a relapse may disappear altogether, with or without treatment, although some symptoms often persist, with repeated attacks happening over several years.
Periods between attacks are known as periods of "remission". These can last for years at a time.
After many years (usually decades), many, but not all people, with relapsing remitting MS go on to develop secondary progressive MS. In this type of MS, symptoms gradually worsen over time without obvious attacks. Some people continue to have infrequent relapses during this stage.
Around half of people with relapsing remitting MS will develop secondary progressive MS within 15-20 years, and the risk of this happening increases the longer you have the condition.
The cause of multiple sclerosis is unknown. It's considered an autoimmune disease in which the body's immune system attacks its own tissues. In the case of MS, this immune system malfunction destroys myelin (the fatty substance that coats and protects nerve fibers in the brain and spinal cord).
Myelin can be compared to the insulation coating on electrical wires. When the protective myelin is damaged and nerve fiber is exposed, the messages that travel along that nerve may be slowed or blocked. The nerve may also become damaged itself.
It isn't clear why MS develops in some people and not others. A combination of genetics and environmental factors appears to be responsible.
These factors may increase your risk of developing multiple sclerosis:
- MS can occur at any age, but most commonly affects people between the ages of 15 and 60.
- Women are about twice as likely as men are to develop MS.
- Family history. If one of your parents or siblings has had MS, you are at higher risk of developing the disease.
- Certain infections.A variety of viruses have been linked to MS, including Epstein-Barr, the virus that causes infectious mononucleosis.
- White people, particularly those of Northern European descent, are at highest risk of developing MS. People of Asian, African or Native American descent have the lowest risk.
- MS is far more common in countries with temperate climates, including Canada, the northern United States, New Zealand, southeastern Australia and Europe.
- Certain autoimmune diseases. You have a slightly higher risk of developing MS if you have thyroid disease, type 1 diabetes or inflammatory bowel disease.
- Smokers who experience an initial event of symptoms that may signal MS are more likely than nonsmokers to develop a second event that confirms relapsing-remitting MS.
People with multiple sclerosis also may develop:
- Muscle stiffness or spasms
- Paralysis, typically in the legs
- Problems with bladder, bowel or sexual function
- Mental changes, such as forgetfulness or mood swings
A complete neurological exam and medical history are needed to diagnose MS.
There are no specific tests for MS. Instead, a diagnosis of multiple sclerosis often relies on ruling out other conditions that might produce similar signs and symptoms, known as a differential diagnosis.
Your doctor is likely to start with a thorough medical history and examination. Your doctor may then recommend:
Lumbar puncture (spinal tap)
Multiple sclerosis MRI scan
- Blood tests, to help rule out other diseases with symptoms similar to MS. Tests to check for specific biomarkers associated with MS are currently under development and may also aid in diagnosing the disease.
- Lumbar puncture (spinal tap), in which a small sample of fluid is removed from your spinal canal for laboratory analysis. This sample can show abnormalities in antibodies that are associated with MS. Spinal tap can also help rule out infections and other conditions with symptoms similar to MS.
- MRI, which can reveal areas of MS (lesions) on your brain and spinal cord. You may receive an intravenous injection of a contrast material to highlight lesions that indicate your disease is in an active phase.
- Evoked potential tests,which record the electrical signals produced by your nervous system in response to stimuli. An evoked potential test may use visual stimuli or electrical stimuli, in which you watch a moving visual pattern, or short electrical impulses are applied to nerves in your legs or arms. Electrodes measure how quickly the information travels down your nerve pathways.
In most people with relapsing-remitting MS, the diagnosis is fairly straightforward and based on a pattern of symptoms consistent with the disease and confirmed by brain imaging scans, such as MRI.
Diagnosing MS can be more difficult in persons with unusual symptoms or progressive disease. In these cases, further testing with spinal fluid analysis, evoked potentials and additional imaging may be needed.
There is no cure for multiple sclerosis. Treatment typically focuses on speeding recovery from attacks, slowing the progression of the disease and managing MS symptoms. Some people have such mild symptoms that no treatment is necessary.
Treatments for MS attacks
- Corticosteroids, such as oral prednisone and intravenous methylprednisolone, are prescribed to reduce nerve inflammation. Side effects may include insomnia, increased blood pressure, mood swings and fluid retention.
- Plasma exchange (plasmapheresis). The liquid portion of part of your blood (plasma) is removed and separated from your blood cells. The blood cells are then mixed with a protein solution (albumin) and put back into your body. Plasma exchange may be used if your symptoms are new, severe and haven't responded to steroids.
Treatments to modify progression
No therapies have shown benefit for slowing the progression of primary-progressive MS.
For relapsing-remitting MS, several disease-modifying therapies are available.
Much of the immune response associated with MS occurs in the early stages of the disease. Aggressive treatment with these medications as early as possible can lower the relapse rate and slow the formation of new lesions.
Many of the disease-modifying therapies used to treat MS carry significant health risks. Selecting the right therapy for you will depend on careful consideration of many factors, including duration and severity of disease, effectiveness of previous MS treatments, other health issues, cost, and child-bearing status.
Treatment options for relapsing-remitting MS include:
- Beta interferons. These medications are among the most commonly prescribed medications to treat MS. They are injected under the skin or into muscle and can reduce the frequency and severity of relapses.
Side effects of beta interferons may include flu-like symptoms and injection-site reactions.
You'll need blood tests to monitor your liver enzymes because liver damage is a possible side effect of interferon use. People taking interferons may develop neutralizing antibodies that can reduce drug effectiveness.
- Glatiramer acetate (Copaxone). This medication may help block your immune system's attack on myelin and must be injected beneath the skin. Side effects may include skin irritation at the injection site.
- Dimethyl fumarate (Tecfidera). This twice-daily oral medication can reduce relapses. Side effects may include flushing, diarrhea, nausea and lowered white blood cell count.
- Fingolimod (Gilenya). This once-daily oral medication reduces relapse rate.
You'll need to have your heart rate monitored for six hours after the first dose because your heartbeat may be slowed. Other side effects include headache, high blood pressure and blurred vision.
- Teriflunomide (Aubagio). This once-daily medication can reduce relapse rate. Teriflunomide can cause liver damage, hair loss and other side effects. It is harmful to a developing fetus and should not be used by women who may become pregnant and are not using appropriate contraception, or their male partner.
- Natalizumab (Tysabri). This medication is designed to block the movement of potentially damaging immune cells from your bloodstream to your brain and spinal cord. It may be considered a first line treatment for some people with severe MS or as a second line treatment in others. This medication increases the risk of a viral infection of the brain called progressive multifocal leukoencephalopathy in some people.
- Alemtuzumab (Lemtrada). This drug helps reduce relapses of MS by targeting a protein on the surface of immune cells and depleting white blood cells. This effect can limit potential nerve damage caused by the white blood cells, but it also increases the risk of infections and autoimmune disorders.
Treatment with alemtuzumab involves five consecutive days of drug infusions followed by another three days of infusions a year later. Infusion reactions are common with alemtuzumab. The drug is only available from registered providers, and people treated with the drug must be registered in a special drug safety monitoring program.
- This immunosuppressant drug can be harmful to the heart and is associated with development of blood cancers. As a result, its use in treating MS is extremely limited. Mitoxantrone is usually used only to treat severe, advanced MS.
Treatments for MS signs and symptoms
- Physical therapy. A physical or occupational therapist can teach you stretching and strengthening exercises and show you how to use devices to make it easier to perform daily tasks.
Physical therapy along with the use of a mobility aid when necessary can also help manage leg weakness and other gait problems often associated with MS.
- Muscle relaxants. You may experience painful or uncontrollable muscle stiffness or spasms, particularly in your legs. Muscle relaxants such as baclofen (Lioresal) and tizanidine (Zanaflex) may help.
- Medications to reduce fatigue.
- Other medications. Medications also may be prescribed for depression, pain, sexual dysfunction, and bladder or bowel control problems that are associated with MS.
Many people with MS use a variety of alternative or complementary treatments or both to help manage their symptoms, such as fatigue and muscle pain.Activities such as exercise, meditation, yoga, massage, eating a healthier diet, acupuncture and relaxation techniques may help boost overall mental and physical well-being, but there are few studies to back up their use in managing symptoms of MS.
Guidelines from the American Academy of Neurology recommend the use of oral cannabis extract for muscle spasticity and pain, but do not recommend cannabis in any other form for other MS symptoms due to a lack of evidence.
The guidelines also do not recommend the use of herbal supplements such as Ginkgo biloba and bee venom or magnetic therapy for MS symptoms.