Absence of polyneuropathy among workers previously diagnosed with solvent-induced toxic encephalopathy

An association between polyneuropathy and occupational exposure to trichlor oethylene, trichloroethane, perchloroethylene, or similar solvents alone or in combination is controversial We sought to determine whether workers pre viously diagnosed with solvent-induced toxic encephalopathy had objective e vidence of polyneuropathy. Thirty railroad workers previously diagnosed wit h toxic encephalopathy were examined in the context of litigation against t heir employers, All described long-term occupational solvent exposure avera ging 20 years in duration (range, 10 to 29 years) and producing acute intox ication on a regular basis. The diagnosis of subclinical or clinical polyne uropathy was established using a combination of symptoms, signs, and nerve conduction study (NCS) measures, consistent with standard clinical practice . Potential confounders were identified. NCS results were compared with his torical controls, including unexposed workers matched by gender, age, and b ody mass index. Dose-response relationships were evaluated using simple lin ear and stepwise regression models, Three workers fulfilled clinical polyne uropathy criteria, The only worker fulfilling NCS criteria for confirmed cl inical polyneuropathy had diabetes mellitus. Mean NCS values for most measu res were similar to control values, and existing differences in sensory amp litudes disappeared when compared with the matched control group. NCS measu res were not significantly influenced by exposure duration or job title. Se paration into groups on the basis of the presence or absence of polyneuropa thy symptoms, previous diagnosis of polyneuropathy, disability status, and severity or type of encephalopathy did not demonstrate significant NCS diff erences. The complaints of these workers claiming neurotoxic injury from oc cupational solvent exposure are not explained by peripheral nervous system dysfunction.