Involvement of the peripheral nervous system in multiple sclerosis.

Multiple sclerosis is a demyelinating disease limited to the central nervous system, but the literature has provided recurring evidence which raises the question of associated peripheral nervous system abnormalities. The prevalence of peripheral neuropathy during multiple sclerosis remains controversial without prospective study. Nevertheless, some data have reported well documented case reports describing the cooccurrence of multiple sclerosis and radiculopathy or mononeuropathy or polyneuropathy in the same patients. By contrast, more frequent subtle nerve abnormalities may be found by using electrophysiological and neuropathological examinations. Some hypotheses have been proposed by Waxman to decipher the electrophysiological and neuropathological findings. The mechanisms for demyelinating disease and peripheral nerve pathophysiology may imply the antigenic properties or the presence of diffusing factors between peripheral nervous system and central nervous system myelin and the molecular plasticity of myelinated fibers.