Multiple Sclerosis
Multiple sclerosis (MS) is an unpredictable, often disabling disease of the central nervous system that disrupts the flow of information within the brain, and between the brain and body. ItÕs an inflammatory disease damaging the insulating covers of nerve cells in the brain and spinal cord. Disrupting the ability of parts of the nervous system to communicate, MS results in a wide range of signs and symptoms, including physical, mental, and sometimes psychiatric problems.
CausesThe cause of MS is unknown; however, it is believed to occur as a result of some combination of environmental factors such as infectious agents and genetics. Theories try to combine the data into likely explanations, but none has proved definitive. While there are a number of environmental risk factors and although some are partly modifiable, further research is needed to determine whether their elimination can prevent MS. The underlying mechanism is thought to be either destruction by the immune system or failure of the myelin-producing cells. MS is usually diagnosed based on the presenting signs and symptoms and the results of supporting medical tests.
ManagementThere 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. 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.Several therapies have proven helpful. The primary aims of therapy are returning function after an attack, preventing new attacks, and disability.
Signs and symptomsA person with MS can have almost any neurological symptom or sign; with autonomic, visual, motor, and sensory problems being the most common. The specific symptoms are determined by the locations of the lesions within the nervous system, and may include loss of sensitivity or changes in sensation such as tingling, pins and needles or numbness, muscle weakness, very pronounced reflexes, muscle spasms, or difficulty in moving; difficulties with coordination and balance; problems with speech or swallowing, visual problems, feeling tired, acute or chronic pain, and bladder and bowel difficulties, among others. Difficulties thinking and emotional problems such as depression or unstable mood are also common. Uhthoff Õs phenomenon, a worsening of symptoms due to exposure to higher than usual temperatures, and LhermitteÕs sign, an electrical sensation that runs down the back when bending the neck.
PrognosisThe expected future course of the disease depends on the subtype of the disease; the individualÕs sex, age, and initial symptoms; and the degree of disability the person has. 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.
ResearchEventually, MS researchers hope genetics will allow doctors to identify people at high risk for the disease and intervene with treatment at very early stages of MS. The approved FDA drugs reduce the frequency of relapses and possibly slow the progression. These drugs are called disease-modifying therapies and must be injected or administered intravenously. Other new drugs for multiple sclerosis that can be taken orally are in clinical trials. If approved, they may offer a welcome end to injections for some patients.
Restoring nervous system function is a hot focus in MS research. Traditionally, experts believed that once myelin was destroyed it could not be repaired. Now we know there is the potential for remyelination. A major research goal is to figure out how to replace the cells that make myelin, which are lost in MS patients. Researchers have   had some success using human embryonic stem cells to generate myelin-producing cells. They are studying the effectiveness of adult stem cells. Growth factors (substances that affect the growth of acell) are also being studied for their ability to repair myelin-producing cells.