Multiple sclerosis (MS), also known as disseminated sclerosis or encephalomyelitis disseminata, is an inflammatory disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to communicate, resulting in a wide range of signs and symptoms, including physical, mental, and sometimes psychiatric problem.
In simple terms,Multiple sclerosis (MS) is a disease in which your immune system attacks the protective sheath (myelin) that covers your nerves. Myelin damage disrupts communication between your brain and the rest of your body. Ultimately, the nerves themselves may deteriorate, a process that's currently irreversible.
While the cause is not clear, the underlying mechanism is thought to be either destruction by the immune system or failure of the myelin-producing cells.Proposed causes for this include genetics and environmental factors such as infections. MS is usually diagnosed based on the presenting signs and symptoms and the results of supporting medical tests.There is no known cure for multiple sclerosis. Treatments attempt to improve function after an attack and prevent new attacks. Medications used to treat MS while modestly effective can have adverse effects and be poorly tolerated. Many people pursue alternative treatments, despite a lack of evidence. The long-term outcome is difficult to predict, with good outcomes more often seen in women, those who develop the disease early in life, those with a relapsing course, and those who initially experienced few attacks.Life expectancy is on average 5 to 10 years lower than that of an unaffected population.
WHAT ARE THE POSSIBLE CAUSES OF MS?
What Role Do Genetics Play in Multiple Sclerosis?
Researchers believe that multiple sclerosis may in part be inherited (genetics contribute to the increased risk of MS seen in family members). First, second and third degree relatives of people with MS are at increased risk of developing the disease. Siblings of an affected person have a 2%-5% risk of developing MS.Researchers believe that there is more than one gene that makes a person more likely to get MS. Some scientists theorize that MS develops because a person is born with a genetic predisposition to react to some environmental agent, which, upon exposure, triggers an autoimmune response.
Sophisticated new techniques for identifying genes may help answer questions about the role of genetics in the development of MS.
What Viruses Are Linked to Multiple Sclerosis?
Some studies have suggested that many viruses such as Epstein-Barr (mononucleosis), varicella zoster, and the hepatitis vaccine may be the cause of MS. To date, however, this belief has not been proven.
Are There Other Potential Factors That Cause Multiple Sclerosis?
There is growing evidence suggesting that hormones, including sex hormones, can affect and be affected by the immune system. For example, both estrogen and progesterone, two important female sex hormones, may suppress some immune activity. Testosterone, the primary male hormone, may also act as an immune response suppressor. During pregnancy, estrogen and progesterone levels are very high, which may help explain why pregnant women with MS usually have less disease activity. The higher levels of testosterone in men may partially account for the fact that women with MS outnumber men with MS by 2-3 to 1.
Smoking has been shown to be an independent risk factor for MS.Stress may be a risk factor although the evidence to support this is weak. Association with occupational exposures and toxins—mainly solvents—has been evaluated, but no clear conclusions have been reached.Vaccinations were studied as causal factors; however, most studies show no association. Several other possible risk factors, such as diet and hormone intake, have been looked at; however, evidence on their relation with the disease is "sparse and unpersuasive". Gout occurs less than would be expected and lower levels of uric acid have been found in people with MS. This has led to the theory that uric acid is protective, although its exact importance remains unknown.
WHAT ARE THE SYMPTOMS OF MS?
Signs and symptoms of multiple sclerosis vary, depending on the location of affected nerve fibers. MS signs and symptoms may include:
1. 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
2. Partial or complete loss of vision, usually in one eye at a time, often with pain during eye movement
3. Double vision or blurring of vision
4. Tingling or pain in parts of your body
5. Electric-shock sensations that occur with certain neck movements, especially bending the neck forward
6. Tremor, lack of coordination or unsteady gait
7. Slurred speech
8. Fatigue
9. Dizziness
10. Problems with bowel and bladder functioN
Disease course
Most people with MS have a relapsing-remitting course, with new symptoms (relapse) that develop over days or weeks and usually improve partially or completely, followed by a quiet period (remission) that can last months or even years. Small increases in body temperature can temporarily worsen signs and symptoms of MS, but that type of event isn't a relapse.
About 60 to 70 percent of people with relapsing-remitting MS eventually develop a steady progression of symptoms, with or without periods of remission (secondary-progressive MS). The worsening symptoms usually include problems with gait. The rate of progression varies greatly among people with secondary-progressive MS.
Some people with MS experience a gradual onset and steady progression of signs and symptoms with no relapses (primary-progressive MS).
NB: management of multiple sclerosis
TESTS AND DIAGNOSIS
There are no specific tests for MS. The diagnosis relies on ruling out other conditions that might produce similar signs and symptoms.
Your doctor is likely to start with a thorough medical history and examination. Your doctor may then recommend:
Blood tests, to help rule out infectious or inflammatory diseases with symptoms similar to MS.
Spinal tap (lumbar puncture), in which a small sample of fluid is removed from your spinal canal for laboratory analysis. This sample can show abnormalities in white blood cells or antibodies that are associated with MS. Spinal tap can also help rule out viral 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 dye to highlight lesions that indicate your disease is in an active phase.
Evoked potential tests
These tests 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
COMPLICATIONS
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
Depression
Epilepsy
PROGNOSIS
The expected future course of the disease depends on the subtype of the disease; the individual's sex, age, and initial symptoms; and the degree of disability the person has. Female sex, relapsing-remitting subtype, optic neuritis or sensory symptoms at onset, few attacks in the initial years and especially early age at onset, are associated with a better course.
The average life expectancy is 30 years from the start of the disease, which is 5 to 10 years less than that of unaffected people. Almost 40% of people with MS reach the seventh decade of life. Nevertheless, two-thirds of the deaths are directly related to the consequences of the disease.Suicide is more common, while infections and other complications are especially dangerous for the more disabled.Although most people lose the ability to walk before death, 90% are capable of independent walking at 10 years from onset, and 75% at 15 years.
