Multiple Sclerosis

Multiple Sclerosis: Greek for "many scars." MS is an autoimmune disease whose cause is unknown. It is a disease of the central nervous system in which the transmission of electrochemical messages is slowed or even halted, resulting in impaired functions.

Multiple sclerosis (MS) is a chronic, sometimes disabling, disease of the central nervous system affecting approximately 400,000 people in the United States, according to the National Multiple Sclerosis Society. It affects three times as many women as men. MS develops more often in Caucasians than in other races. About 200 new cases of MS are diagnosed in the United States every week.
The cause of MS is still unknown, but most researchers think that MS results from an abnormal response by the body's immune system. Some researchers believe this abnormal immune response could be caused by a virus, although it is unlikely that there is just one virus responsible for triggering the condition. Researchers do know that MS is not contagious. And while it is not an inherited disease, genetic susceptibility plays a role. There is a higher risk for MS in families where it has already occurred. Other possible causes include environmental triggers, trauma and heavy metals.
It is believed that MS is an autoimmune disease. In MS, the immune system—for reasons still not understood—attacks and destroys myelin and the oligodendrocytes (oligo, few; dendro, branches; cytes, cells) that produce it. Though the body usually sends in immune cells to fight off bacteria and viruses, in MS they misguidedly attack the body's own healthy nervous system, thus the term autoimmune disease. Rheumatoid arthritis and lupus are other types of autoimmune diseases.
In multiple sclerosis, these misdirected immune cells (certain types of lymphocytes, T-cells and killer cells) attack and consume myelin, damaging the myelin sheath—the fatty insulation surrounding nerve cells in the brain and spinal cord. Myelin acts like the rubber insulation found in an electric cable and facilitates the smooth transmission of high-speed messages between the brain and the spinal cord and the rest of the body. As areas of myelin are affected, messages are not sent efficiently or they never reach their destination.
Eventually, there is a buildup of scar tissue (sclerosis) in multiple places where myelin has been lost; hence the disease's name: multiple sclerosis. These plaques or scarred areas, which only are a fraction of an inch in diameter, can interfere with signal transmission. The underlying nerve also may be damaged, further worsening symptoms and reducing the degree of recovery. The disease can manifest itself in many ways. Sometimes the diseased areas cause no apparent symptoms, and sometimes they cause many; this is why the severity of problems varies greatly among people affected with MS.
Multiple sclerosis usually strikes in the form of attacks or exacerbations. This is when at least one symptom occurs, or worsens, for more than 24 hours. The symptom(s) can last for days, weeks, months or indefinitely.
The most common type of multiple sclerosis is relapsing-remitting MS. It is characterized by periods of exacerbation followed by periods of remission. The remissions occur because nervous system cells have ways of partially compensating for their loss of ability. There's no way to know how long a remission will last after an attack—it could be a month or it could be several years. But disease activity usually continues at a low, often almost indiscernible level, and MS often worsens over time as the signal-transmitting portion of the cells—the axons—are damaged.
Most commonly, multiple sclerosis starts with a vague symptom that disappears completely within a few days or weeks. Temporary weakness, tingling or pain in a limb can be a first sign. Ataxia (general physical unsteadiness and problems with coordination), temporary blurring or double vision, memory disturbances and fatigue are also symptoms that can appear suddenly and then vanish for years after the first episode, or in some cases never reappear.
The symptoms of MS vary greatly, as does their severity, depending on the areas of the central nervous system that are affected. Most people suffer minor effects. The disease can, however, completely disable a person, preventing him or her from speaking and walking in the most extreme cases. The bodily functions that are commonly affected by MS are:
vision
coordination
strength
sensation
speech and swallowing
bladder and bowel control
sexuality
cognitive function (thinking, concentration and short-term memory)
A varying degree of dysfunction may occur within these general areas. For instance, one person may suffer blurred vision while another may suffer double vision. Or one person may suffer from tremors while another will experience clumsiness of a particular limb.
Specific symptoms associated with MS can include:
fatigue: a debilitating kind of general fatigue that is unpredictable and out of proportion to the activity; fatigue is one of the most common (and one of the most troubling) symptoms of MS
cognitive function: short-term memory problems and difficulty concentrating and thinking, typically not severe enough to seriously interfere with daily functioning, although sometimes it does. Judgment and reasoning may also be affected
visual disturbances: blurring of vision, double vision (diplopia), optic neuritis, involuntary rapid eye movement and (rarely) total loss of sight
balance and coordination problems: loss of balance, tremor, unstable walking (ataxia), dizziness (vertigo), clumsiness of a limb and lack of coordination
weakness: usually in the legs
spasticity: altered muscle tone can produce spasms or muscle stiffness, which can affect mobility and walking
altered sensation: tingling, numbness (paresthesia), a burning feeling in an area of the body or other indefinable sensations
abnormal speech: slowing of speech, slurring of words, and changes in rhythm of speech
difficulty in swallowing (dysphagia)
bladder and bowel problems: the need to urinate frequently and/or urgently, incomplete emptying or emptying at inappropriate times, constipation and loss of bowel control
sexuality and intimacy: impotence, diminished arousal and loss of sensation
pain: facial pain and muscle pains
sensitivity to heat: this often causes symptoms to get worse temporarily
Though these are some of the symptoms commonly associated with MS, not all people with MS will experience all of them. Most will experience more than one symptom, however. There is no typical case of MS. Each is unique.
Today, life expectancy for those with MS is normal or close to normal.
Most people with MS begin experiencing symptoms between the ages of 20 and 50. But initial symptoms may be vague, may come and go with no pattern or may be attributed to other factors or conditions. For instance, a woman who experiences sudden bouts of vertigo once every few months may explain away the symptom by linking it to her menstrual cycle. Or, perhaps, someone who suddenly has a bit of blurry vision may blame too many hours at the office.