A chronic progressive nervous disorder involving loss of myelin sheath around certain nerve fibers; SYN. MS, disseminated sclerosis.
(MS) or disseminated sclerosis; Incurable chronic disease of the central nervous system, occurring in young or middle adulthood. Most prevalent in temperate zones, it affects more women than men. It is characterized by degeneration of the myelin sheath that surrounds nerves in the brain and spinal cord.
Depending on where the demyelination occurs—which nerves are affected—the symptoms of MS can mimic almost any neurological disorder. Typically seen are unsteadiness, ataxia (loss of muscular coordination), weakness, speech difficulties, and rapid involuntary movements of the eyes. The course of the disease is episodic, with frequent intervals of remission. Its cause is unknown, but it may be initiated in childhood by some environmental factor, such as infection, in genetically susceptible people.
In 1993 interferon beta 1b became the first drug to be approved in the United States for treating MS. It reduces the number and severity of relapses, and slows the formation of brain lesions giving hope that it may slow down the progression of the disease.