Etiology and pathology of multiple sclerosis

1. Big picture

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by multifocal demyelinating plaques, inflammation, gliosis/scarring, and axonal degeneration.

The key exam idea:

MS is not simply “loss of myelin.” It is an immune-mediated CNS disease with inflammation, demyelination, oligodendrocyte injury, partial remyelination, gliosis, and progressive axonal loss.

The etiology is still not completely known, but MS is best understood as a multifactorial disease developing in genetically susceptible individuals exposed to environmental and immunological triggers.

The most important risk factors ar