What is (are) Multiple sclerosis ?
Multiple sclerosis (MS) is a degenerative disorder that affects the central nervous system, specifically the brain and the spinal cord. The disorder is characterized by destruction of the myelin, the fatty tissue that surrounds and protects the nerve fibers and promotes the transmission of nerve impulses, and damage to nerve cells. The symptoms vary widely from person to person, and may include sensory disturbances in the limbs, problems with muscle control, tremors, muscle stiffness (spasticity), exaggerated reflexes (hyperreflexia), weakness, difficulty walking, poor bladder control, and vision problems. Most patients have periods during which they have symptoms (clinical attacks). The clinical attacks are typically followed by periods without any symptoms (remission). After several years, the symptoms worsen continuously. Multiple sclerosis is considered an autoimmune disorder but the exact cause is unknown. Risk factors for developing multiple sclerosis include genetic factors like changes in the HLA-DRB1 gene and in the IL7R gene and environmental factors, such as exposure to the Epstein-Barr virus, low levels of vitamin D, and smoking. The goal of treatment of MS is to decrease attacks and the inflammation within the central nervous system.