Multiple Sclerosis and Related Disorders

Multiple sclerosis (MS) is a relatively common cause of neurologic symptoms and disability in young adults. The distinguishing pathologic features of MS are loss of myelin and inflammation in the central nervous system (CNS). The myelin sheath is essential for rapid conduction of nerve signals along large-diameter axons. Oligodendrocytes produce and maintain myelin in the CNS, and Schwann cells produce and maintain myelin in the peripheral nerves. In addition to MS, there are a number of related disorders causing demyelination, inflammation, or both in the CNS. This chapter discusses MS and related disorders, including neuromyelitis optica, optic neuritis, acute disseminated encephalomyelitis, transverse myelitis, Behçet syndrome, neurosarcoidosis, inherited demyelinating diseases (leukodystrophies, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy [CADASIL]), and virus-induced demyelination (progressive multifocal leukoencephalopathy, subacute sclerosing panencephalitis). The section on MS covers epidemiology, etiology/genetics, pathogenesis, diagnosis, differential diagnosis, management, and prognosis. Figures include organization of the m