Urinary excretion of 2,5‐hexanedione and peripheral polyneuropathies in workers exposed to hexane

Abstract
Forty shoe factory workers who were exposed to hexane were investigated to see if there was a correlation between electroneuromyographic changes indicative of neuropathy and urinary excretion of 2,5‐hexanedione. Urinary samples were analyzed for the presence of the metabolic products of n‐hexane and its isomers. Electrodiagnostic examination was carried out following the urinary sampling. A rating scale was used to obtain a cumulative numeric index of electrodiagnostic findings. 2,5‐Hexane‐dione and γ‐valerolactone were discovered in all cases, while 2‐hexanol was found in 11 cases. 2,5‐Hexanedione was the main metabolite in most cases (39 of 40). Only in 1 case was a low level of 2‐methyl‐2‐pentanol detected; 3‐methyl‐2‐pentanol was never detected. Metabolic products of cyclohexane were present in about one‐fifth of the cases, while trichloroethanol, a metabolic product of trichloroethylene, was nearly always present, all at very low concentrations. Electromyographic abnormalities significant for early detection of toxic polyneuropathy were found in 14 cases. A statistically significant correlation of the electroneuromyographic scoring on the urinary concentrations of measured metabolites was observed only with 2,5‐hexanedione and γ‐valerolactone, both derived from n‐hexane. Since γ‐valerolactone is probably not a true metabolite of n‐hexane, our results support the hypothesis that polyneuropathies in shoemakers are due to 2,5‐hexanedione. For practical purposes the urinary concentration of 2,5‐hexanedione can serve as a predictive measurement for early detection of neurotoxic lesions at preclinical states.