MS can cause a variety of symptoms and some people may only experience one or two, while others may have a number of symptoms that need to be addressed.
Commonly seen symptoms include: visual disorders, slurred speech, swallowing disorders, numbness, dizziness and vertigo; bladder, bowel, and sexual dysfunction; spasticity, weakness, tremor, chronic aching pain, mild cognitive difficulties, and impaired mobility.
These symptoms are often compounded by extreme fatigue, which may be worse
in the afternoon, sometimes relating to a
rise in body temperature. Most symptoms may be temporarily increased by heat
intolerance - a classic MS symptom, where a rise in temperature (internally
or externally) causes a person to feel much worse. Other common symptoms
can include
depression and migraine headache.
Over the years, MS classifications and their definitions have evolved to
more accurately describe how each form of MS behaves. Given the unpredictability
of MS, categorizing the similarities is extremely important in the assessment
of clinical
trials and for assisting medical professionals with the care of people with
MS.
On average, 80 percent of those with MS begin with the relapsing-remitting form of MS (RRMS). What distinguishes this type of MS from other types are the temporary symptom flare-ups or exacerbations (also referred to as relapses, attacks, or bouts), which typically last for one to three months. These are followed by a complete or partial recovery (when symptoms are said to remit).
Many people may go into remission for a year or more; the mean relapse frequency is about once every two years, although this can vary greatly. Between relapses, patients may remain symptom free, or only experience mild changes that did not fully remit following the exacerbation. Their condition does not worsen between relapses.
People
with RRMS usually present with sensory disturbances (such as numbness
or tingling), unilateral optic neuritis (inflammation of the optic nerve causing
visual changes or loss; usually occurring in one eye) or diplopia (double
vision). Objects may also appear to jump as a result of the eyes not
coordinating together well. Visual changes are often temporary.
Other initial symptoms with RRMS may include limb weakness, clumsiness, fatigue, bladder and bowel problems, and Lhermitte's sign. The latter is a tingling sensation that radiates down the spine and into the limbs when the neck is flexed.
More than 90 percent of individuals with RRMS will enter a second phase of RRMS, known as secondary-progressive MS (SPMS), within 25 years. This phase is reached when the person experiences a progressive worsening of symptoms. SPMS may occur with or without superimposed relapses.
A small subgroup of individuals with RRMS may follow a relatively benign course, still doing well - with little or no disability - after 20 years with the disease. This subgroup represents about 10 percent of people with MS. Unfortunately, this is a diagnosis that is made retrospectively, because some of those who appear to have benign MS go on to progressive disease later in life.
While the majority of patients (80 percent) are diagnosed with RRMS, another 15 percent fall under the heading of primary-progressive MS (PPMS). This form of MS presents a gradual accumulation of neurologic deficits from the onset, without the presence of relapses and remissions. Unlike RRMS where women are twice as likely to be diagnosed than men, PPMS is equally divided between the genders.
Two other types of MS exist, but both are rare and seldom mentioned other than in a clinical setting. The first is progressive-relapsing MS (PRMS), which shows a progressive course from the beginning, but with which the person also experiences acute relapses. While PRMS is uncommon, some experts estimate that as many as five percent of patients have this type of MS. The second type is malignant or fulminant MS, which describes a rapidly progressing disease course.
Predicting
a person's prognosis is difficult. People with MS experience various symptoms,
and the disease progresses at different rates. In general, a more favorable
prognosis may be given if the person is female, younger at the age of onset,
experiencing initial symptoms that are visual or sensory, initially diagnosed
with RRMS, having relapses that are far apart, and experiencing a complete,
or nearly complete, recovery after each relapse.
According to earlier statistics, before any long-term treatments were available for MS, about half of those with MS after an average of 17 years tended to need some assistance with walking distances of more than 100 yards. After 50 years with the disease, up to half of people with MS were no longer mobile.
Prognosis, however, is just a likely outcome based on past experience - and does not take into consideration each individual person, his or her individual symptoms and disease progression, or the response to long-term treatments available now and in the future. With this in mind, people with MS should look forward to an ever-improving prognosis and should not rely on assumptions from past statistics. Most people with MS may now be helped by these new disease-modifying medications.