What Is Multiple Sclerosis?
Multiple sclerosis (MS) is an autoimmune disease in which the body's immune system attacks its own central nervous system (CNS), which is made up of the brain and spinal cord. With MS, the immune system attacks and damages or destroys the myelin, a substance that surrounds and insulates the nerves, causing a distortion or interruption in nerve impulses traveling to and from the brain. This results in a wide variety of symptoms.
Who Can Get Multiple Sclerosis?
Multiple sclerosis is estimated to affect 2.3 million people worldwide. Most people are diagnosed between the ages of 20 to 50, though it can also occur in young children and the elderly. It is three times more common in women than in men, and is more prevalent among Caucasians than other ethnicities. MS is believed to have a genetic component as people with a first degree relative with the disease have a higher incidence than the general population.
What Causes Multiple Sclerosis?
The exact cause of multiple sclerosis is unknown, but it is believed to be any combination of immunologic, environmental, infectious, or genetic factors. Researchers are examining the possible role of viruses in the cause of MS, but this is still unproven.
When Multiple Sclerosis Attacks
Multiple sclerosis (MS) is an autoimmune disorder where the body perceives its own myelin (the sheath around the nerves) as an intruder and attacks it, as it would a virus or other foreign infectious agent. This causes inflammation and degeneration of the myelin and can lead to demyelination, or stripping of the myelin covering of the nerves. It can also cause scarring. This causes electrical impulses to travel more slowly along the nerves resulting in deterioration of function in body processes such as vision, speech, walking, writing, and memory.
Is Multiple Sclerosis Inherited?
While multiple sclerosis is not hereditary, genetics are believed to play a role. In the U.S., the chances of developing MS are one in 750, or a 0.1% chance. Having a first-degree relative (parent, sibling) increases the risk to up to 5%. An identical twin of someone with MS has a 25% chance of being diagnosed with the disorder. It is thought there is an outside trigger and genetics only makes certain people susceptible to getting MS which is why the disease is not considered hereditary – genes may make a person more likely to develop the disease but it is believed there still is an additional outside trigger that makes it happen.
What Are the Types of Multiple Sclerosis?
There are four different types of multiple sclerosis that have been identified and each type can have symptoms ranging from mild to severe. The different types of MS can help predict the course of the disease and the patient's response to treatment. The four types of MS are discussed on the following slides.
Relapsing-Remitting (RR) MS
Relapsing-remitting multiple sclerosis (RR-MS) is the most common type of MS, affecting about 85% of sufferers. RR-MS is defined by inflammatory attacks on the myelin and nerve fibers causing a worsening of neurologic function. Symptoms vary from patient to patient, and symptoms can flare up (called relapses or exacerbations) unexpectedly, and then disappear (remission). The most common symptoms of RR-MS include fatigue, numbness, problems with vision, muscle spasms or stiffness, bowel and bladder function problems, and cognitive difficulties.
Primary-Progressive (PP) MS
Primary-progressive multiple sclerosis (PP-MS) is characterized by steady worsening of neurologic functioning, without any relapses or remissions. There may be occasional plateaus, but overall the progression of the disability is continuous. This form of MS occurs equally in men and women, and the age of onset is about 10 years later than in relapsing-remitting MS.
Secondary-Progressive (SP) MS
Secondary-progressive multiple sclerosis (SP-MS) is a form of MS that follows relapsing-remitting MS. The majority of people diagnosed with RR-MS will eventually transition to having SP-MS. After a period of relapses (also called attacks, or exacerbations) and remissions the disease will start to progress steadily. People with SP-MS may or may not experience remissions.
Progressive-Relapsing (PR) MS
Progressive-relapsing multiple sclerosis (PR-MS) is the least common form of MS, occurring in about 5% of patients. People with PR-MS experience steady disease progression and worsening neurological function as seen in primary-progressive multiple sclerosis (PP-MS), along with occasional relapses like people with relapsing-remitting multiple sclerosis (RR-MS).
What Are the Symptoms of Multiple Sclerosis?
Symptoms of multiple sclerosis may be single or multiple and may range from mild to severe in intensity and short to long in duration. These include:
- Numbness or tingling
- Dizziness or vertigo
- Sexual dysfunction
- Emotional instability
- Difficulty walking
- Muscle spasms
- Vision problems
- Bladder or bowel problems
- Cognitive changes
How Is Multiple Sclerosis Diagnosed?
Multiple sclerosis is often difficult to diagnose as symptoms are so varied and can resemble other diseases. It is often diagnosed by a process of exclusion – that is, by ruling out other neurological diseases – so the diagnosis of MS may take months to years. A physician will do a complete history and neurological exam, along with tests to evaluate mental, emotional and language functions, strength, coordination, balance, reflexes, gait, and vision.
Tests to help confirm the diagnosis of MS include:
- Electrophysiological test
- Cerebrospinal fluid exam (spinal tap, lumbar puncture)
- Evoked potential (EP) tests
- Optical coherence tomography (OCT)
- Blood tests
How Is Multiple Sclerosis Diagnosed?
One of the main ways to diagnose multiple sclerosis is an MRI (magnetic resonance imaging). Characteristic areas of demyelination will show up as lesions on an MRI scan. On the left is a brain MRI of a 35-year-old man with relapsing remitting multiple sclerosis that reveals multiple lesions with high T2 signal intensity and one large white matter lesion. The right image shows the cervical spinal cord of a 27-year-old woman representing a multiple sclerosis demyelination and plaque (see arrow).
How Is Multiple Sclerosis Treated?
There are several aspects to treating multiple sclerosis.
- Modifying the disease – there are several drugs that can reduce the severity and frequency of relapses
- Treating exacerbations (or attacks) with high dose corticosteroids
- Managing symptoms
- Rehabilitation both for fitness and to manage energy levels
- Emotional support
Multiple Sclerosis Treatment
Treatment for multiple sclerosis may include drugs to manage attacks, symptoms, or both. Many medications carry the risk of some side effects so patients need to manage their treatment with their doctors.
Corticosteroids are drugs that reduce inflammation in the body and affect the function of the immune system. They are often used to manage MS attacks, but can have numerous side effects.
Multiple Sclerosis Treatment Medications
There are currently 10 medications approved for disease modification:
Interferons for relapsing multiple sclerosis:
- Interferon beta-1b (Betaseron and Extavia)
- Interferon beta-1a (Rebif)
- Interferon beta-1a (Avonex)
Other medications approved for relapsing multiple sclerosis:
- Glatiramer acetate (Copaxone)
- Natalizumab (Tysabri)
- Mitoxantrone (Novantrone)
- Fingolimod (Gilenya)
- Teriflunomide (Aubagio)
- Dimethyl fumarate (Tecfidera)
How Are the Physical Manifestations of MS Treated?
Many medications are used to treat and manage symptoms associated with multiple sclerosis. This table (continued on the next slide) lists common multiple sclerosis symptoms, and the treatments often used, along with possible complications.
Physical Manifestations of MS Treated (continued)
Continued from the last slide, this table lists common multiple sclerosis symptoms, and the treatments often used, along with possible complications.
What Are the Future Directions for Managing Multiple Sclerosis?
There has been a lot of progress over the years in managing multiple sclerosis, and research is ongoing into new therapies. There are several new avenues of research including techniques to allow brain cells to generate new myelin or prevent the death of nerves. Other research involves use of stem cells that might be implanted into the brain or spinal cord to regrow the cells that have been destroyed by the disease. Some therapies being investigated include methods that would improve the nerve impulse signals. In addition the effects of diet and the environment on multiple sclerosis are being investigated.
Multiple Sclerosis At A Glance
- Multiple sclerosis (MS) is an autoimmune disease that progressively damages the nerves of the brain and spinal cord.
- Any sensory or motor (muscular) function in the body may be affected by the nerves damaged from MS.
- The cause of multiple sclerosis is unknown, but it is believed to be a combination of genetic, immunological, infectious, and/or environmental factors.
- There are four different types of multiple sclerosis and symptoms range from mild to severe. The different types of MS can help predict the course of the disease and the patient's response to treatment.