Polyneuropathy. Facts and fancies.

Area of Science:

• Neurology
• Pathology

Background:

• Polyneuropathy is a common neurological disorder with diverse etiologies.
• Clinical and electrophysiological assessments are standard diagnostic tools, but their correlation with underlying nerve pathology can be complex.

Purpose of the Study:

• To investigate the relationship between clinical, electrophysiological, and histological findings in patients with polyneuropathy.
• To determine the specificity of nerve conduction studies and electromyography in identifying neuropathic pathology.

Main Methods:

• Analysis of clinical data, electrophysiological measurements (nerve conduction studies, electromyography), and sural nerve biopsies from 167 patients.
• Histological examination of teased nerve fibers to assess demyelination, remyelination, and axonal loss.

Main Results:

• Histological abnormalities were found even with normal electrophysiological findings, but not vice versa.
• Neither electrophysiological tests nor histology were specific for the etiology or type of neuropathy.
• Axonal degeneration explained "proportionate" slowing in conduction, while "disproportionate" slowing suggested other causes, particularly in hypertrophic peroneal muscular atrophy and postgastrectomy neuropathy.

Conclusions:

• Histological examination of sural nerves provides valuable insights into polyneuropathy pathology, complementing electrophysiological data.
• Electrophysiological methods alone are insufficient to determine the specific underlying nerve pathology.
• The mechanisms of disproportionate nerve conduction slowing, especially when not due to demyelination, require further investigation.