multiple sclerosis

Multiple sclerosis (abbreviated MS, also known as disseminated sclerosis or encephalomyelitis disseminata) is a disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms.[1] Disease onset usually occurs in young adults, and it is more common in females.[1] It has a prevalence that ranges between 2 and 150 per 100,000.[2] MS was first described in 1868 by Jean-Martin Charcot.[3]

MS affects the ability of nerve cells in the brain and spinal cord to communicate with each other. Nerve cells communicate by sending electrical signals called action potentials down long fibers called axons, which are wrapped in an insulating substance called myelin. In MS, the body's own immune system attacks and damages the myelin. When myelin is lost, the axons can no longer effectively conduct signals.[4] The name multiple sclerosis refers to scars (scleroses—better known as plaques or lesions) in the white matter of the brain and spinal cord, which is mainly composed of myelin.[3] Although much is known about the mechanisms involved in the disease process, the cause remains unknown. Theories include genetics or infections. Different environmental risk factors have also been found.[4][5]