Peripheral neuropathies during hypoxaemic chronic obstructive airways disease.

Peripheral nervous system alterations during chronic obstructive airways disease (COAD) with respiratory insufficiency seem more frequent than usual neurological practice would suggest. Almost a third of COAD patients have clinical evidence of peripheral neuropathy and two thirds have electrophysiological abnormalities. The presentation consists of a polyneuropathy often subclinical or with predominantly sensory signs, which has the neurophysiological and pathological features of predominantly axonal neuropathy. The presumed etiopathogenic factors are multiple: chronic hypoxia, tobacco smoke (which contains at least three neurotoxic constituents) alcoholism, malnutrition and adverse effects of certain drugs. Hypoxia probably plays the leading part, either by direct action on nerves fibres or by enhancing the effects of other neurotoxic factors or deficiencies.