Multiple Sclerosis is a disease in which the brain, spinal cord and nerves to the eyes (optic nerves) can be attacked by your immune system.
Specifically, the attack is directed at the coating of nerve cells called myelin. Myelin allows electrical signals to travel along nerves rapidly. When your immune cells attack myelin, these signals can be delayed or blocked. This prevents the nerve cells from “talking” to one another. The result of this inflammation against myelin can be neurological symptoms such as numbness, weakness, visual loss, double vision and imbalance. Attacks of inflammation causing symptoms lasting more than 24 hours are called relapses or exacerbations. Some attacks will last only 1 day but many last a few weeks to several months. Generally, the myelin can be repaired so recovery can occur. If the inflammation is severe enough, the actual nerves may be cut. This may result in permanent disability.
You Are Not Alone
Over 900,000 Americans are living with multiple sclerosis. Most people are 20 to 40 when diagnosed, but both children and older adults are often diagnosed. Genetic factors play a role, but most people do not have a family history of MS. If one identical twin has MS, only one third of the other twins will develop MS despite that the twins share the same genetic background. Fortunately, the chance of passing MS on to your children is low. For example, a daughter has a 3-5% risk and a son has a 1-3% risk of developing MS if their mother has MS.
Environmental factors may influence your risk of developing MS. Low Vitamin D is a risk factor for developing MS and has been associated with more relapses, new MRI and more disability. Exposure to Epstein-Barr virus (infectious mononucleosis) has been associated with an increased risk of developing MS although most people have been exposed to this virus. Smoking before age 17 years old increases the risk of getting multiple sclerosis and associated with higher rates of physical and cognitive disability. Childhood obesity also increases the risk of developing MS.
Relapse and Recovery
About 85% of patients initially have attacks or relapses with full or partial recovery. This pattern is called relapsing remitting MS. Fifteen percent of patients never have attacks, but only a slowly progressive course called primary progressive MS. The most common symptom of progressive disease is weakness, leading to trouble walking. Most patients without treatment will switch from a relapsing remitting to a more progressively worsening course called secondary progressive MS.
The time from the relapsing remitting phase to secondary progressive phase varies with some patients in only 7 years and others not for 30 years. About 10% of patients never develop progressive disease without treatment, but it is impossible to predict who will be this fortunate. The good news is that treatment for relapsing disease will help you fight MS and reduce your risk of developing disability.