Multiple sclerosis (MS) is a chronic, degenerative condition that affects the central nervous system. It interferes with nerves that carry signals from the brain to other parts of the body and can cause a variety of symptoms which can range from mild to debilitating.
The central nervous system consists of the brain, optic nerve, and spinal cord. Nerve fibers branch out from the spinal cord to reach every part of the body. You can think of a nerve fiber as being similar to a wire that is coated with plastic insulation.
Brain signal travels through the fibers at the center of the nerve, which are surrounded by a protective covering called the myelin sheath. Myelin is important for the health of nerve cells because it protects the nerves and helps make sure the signals from the brain travel smoothly.
In multiple sclerosis, the body’s own immune system becomes confused and attacks the nerve cells. When the area around nerves becomes irritated and inflamed, the myelin sheath can become damaged. In essence, the body’s own immune cells eat away at the myelin sheath, exposing the nerve fibers inside.
When the myelin sheath is damaged, electrical signals are disrupted in that area. Depending on how bad the damage is, the brain’s signal may move more slowly through that area, or may not be able to pass any further along that nerve path.
MS can be difficult to diagnose because symptoms vary significantly from person to person depending on which nerves are attacked by the immune system and how badly they are damaged. Early in the disease, multiple sclerosis symptoms may seem to come and go and may even disappear for several months before returning.
In general, MS interferes with body functions that are controlled by the nervous system such as walking, vision, speech, memory and the ability to write. The symptoms of multiple sclerosis may worsen if body temperature is elevated such as by fever, being out in the sun, or taking a hot bath, and may also get worse during stress.
Approximately 400,000 people in the United States have multiple sclerosis.