Multiple sclerosis
An autoimmune, T-cell-mediated attack on CNS myelin that produces neurological deficits disseminated in time and space, because demyelinating plaques occur at different sites of the central nervous system on different occasions, each slowing or blocking conduction along the affected pathway.
First principles
MS is focal demyelination, and demyelination slows or blocks conduction
Myelin insulates axons and allows fast saltatory conduction. An autoimmune inflammatory attack strips myelin from CNS axons at a focal plaque, targeting oligodendrocytes rather than the Schwann cells of peripheral nerve. Demyelinated axons conduct slowly or fail intermittently, especially when already stressed, which is why symptoms are exacerbated by heat or exertion, known as Uhthoff's phenomenon, because raised temperature further impairs conduction in partially demyelinated axons.
Educational content pending clinical review. Not medical advice.