Multiple sclerosis

Abstract

Multiple sclerosis (MS) is a complex multifactorial polygenic disease, infl uenced by various factors including age, gender, hormonal, and environmental factors. Despite an unknown etiology, the (histo-) pathological hallmarks of MS lesions are well defi ned and include demyelination and inflammation of various brain regions. The most widely accepted hypothesis explaining MS is that autoreactive T and B cells and autoantibodies induce myelin damage, neuroinfl ammation, and neurodegeneration, making MS part of the group of autoimmune diseases (see also chapters “Rheumatoid arthritis” and “ Diabetes mellitus ”). MS affects persons of all ages, but symptoms are most likely to appear in individuals between 20 and 50 years of age. The estimated prevalence of MS is about 2.5 million people worldwide and is two to three times higher in women than in men. The diagnosis of MS requires evidence of lesions in at least two separate areas of the central nervous system (CNS), including the brain, spinal cord, and optic nerves (dissemination in space), and evidence that new lesions developed at least 1 month apart (dissemination in time). Other potential causes for CNS lesions must be excluded. Technically, diagnosis includes medical history, neurologic exam, and magnetic resonance imaging (MRI) to detect dissemination in space and time, visual-evoked potential measurement, cerebrospinal fl uid analysis to detect the levels of immune system proteins and the presence of oligoclonal bands (immunoglobulin bands in gel electrophoresis analysis), and blood tests to rule out conditions causing symptoms similar to MS. The McDonald diagnostic criteria additionally require the fi rst MS attack, which is also known as clinically isolated syndrome (CIS), to be clinical, with features typical or suggestive of MS and with objective abnormalities on neurologic examination. Such symptoms have to last for at least 24 h.