Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system
(the brain and spinal cord).
MS afflicts more women than men. The disorder most commonly
begins between ages 20 and 40, but can be seen at any age.
The exact cause is not known, but MS is believed to result from damage to the myelin
sheath, the protective material which surrounds nerve cells. It is a progressive
disease, meaning the nerve damage (neurodegeneration) gets worse over time.
In addition to nerve damage, another part of MS is inflammation. Inflammation occurs
when the body's own immune cells attack the nervous system. The inflammation destroys
the myelin, leaving multiple areas of scar tissue (sclerosis). It also causes nerve
impulses to slow down or become blocked, leading to the symptoms of MS. Repeated
episodes, or flare-ups, of inflammation can occur along any area of the brain and
Symptoms vary because the location and extent of each attack varies. Usually episodes
that last days, weeks, or months alternate with times of reduced or no symptoms
Recurrence (relapse) is common, although non-stop progression without periods of
remission may also occur.
Researchers are not sure what triggers an attack. Patients with MS typically have
a higher number of immune cells than a healthy person, which suggests that an
immune response might play a role. The most common theories point to a virus
or genetic defect, or a combination of both. There also appears to be a genetic
link to the disease.
MS is more likely to occur in northern Europe, the northern United States, southern
Australia, and New Zealand, than in other areas. Geographic studies indicate an environmental factor may be involved.
People with a family history of MS, and those who live in a geographical area with
a higher incidence rate for MS, have a higher risk of the disease.
- Decreased ability to control small movements
- Decreased attention span
- Decreased coordination
- Decreased judgment
- Decreased memory
- Difficulty speaking or understanding speech
- Double vision
- Eye discomfort
- Facial pain
- Loss of balance
- Movement problems that slowly progress, beginning in the legs
- Muscle atrophy
- Muscle spasms, especially in the legs
- Muscle spasticity (uncontrollable spasm of muscle groups)
- Numbness, or abnormal sensation in any area
- Pain in the arms or legs
- Paralysis in one or more arms or legs
- Slurred speech
- Tremor in one or more arms or legs
- Uncontrollable rapid eye movements
- Urinary frequency (frequent need to urinate)
- Urinary hesitancy (difficult to begin urinating)
- Urinary urgency (strong urge to urinate)
- Urine leakage (incontinence)
- Vision loss, usually affects one eye at a time
- Walking / gait abnormalities
- Weakness in one or more arms or legs
Additional symptoms that may be associated with this disease:
- Hearing loss
Note: Symptoms may vary with each attack. They may last days to months, then reduce
or disappear, then recur periodically. With each recurrence, the symptoms are different
as new areas are affected. Fever can trigger or worsen attacks, as can hot baths,
sun exposure, and stress.
Symptoms of MS may mimic many other neurologic disorders. Diagnosis is made by ruling
out other conditions.
A history of at least two attacks separated by a period of reduced or no symptoms
may be a sign of relapsing-remitting MS.
If the health care provider can see decreases in any functions of the central nervous
system (such as abnormal reflexes), a diagnosis of MS may be suspected.
A neurological exam may show localized decreases in nerve function. This may include
decreased or abnormal sensation, decreased ability to move a part of the body, speech
or vision changes, or other loss of neurologic functions. The type of neurologic deficit usually indicates the location of the damage to the nerves.
There may be a positive Babinski's reflex.
Eye examination may show abnormal pupil responses, changes in the visual fields or eye movements, rapid eye movements triggered by movement
of the eye, decreased visual acuity, or problems with the internal structures of the
Tests that indicate or confirm multiple sclerosis include:
The outcome is variable and unpredictable. Although the disorder is chronic and incurable, life expectancy can be normal or nearly so. Most people with MS continue to walk and function at work with minimal disability for 20 or more years.
The factors felt to best predict a relatively benign course are female gender, young age at onset (less than 30 years), infrequent attacks, a relapsing-remitting pattern, and low burden of disease on imaging studies.
The amount of disability and discomfort varies with the severity and frequency of attacks and the part of the central nervous system affected by each attack. Commonly, there is initially a return to normal or near-normal function between attacks. As the disorder progresses, there is progressive loss of function with less improvement between attacks.
Researchers are not sure what causes MS. Patients with MS typically have a higher number of immune cells than a healthy person, which suggests that an immune response might play a role. The most common theories point to a virus or genetic defect, or a combination of both. There also appears to be a genetic link to the disease.
MS is more likely to occur in northern Europe, the northern United States, southern Australia, and New Zealand, than in other areas. Geographic studies indicate an environmental factor may be involved.
People with a family history of MS, and those who live in a geographical area with a higher incidence rate for MS, have a higher risk of the disease.