[Change in peripheral nervous conduction velocity in patients with occupational chronic mercury poisoning and related influencing factors].

Objective: To investigate the change in peripheral nervous conduction velocity in patients with occupational chronic mercury poisoning and related influencing factors. Methods: From February 2011 to December 2014, urinary mercury examination and neural electromyography were performed for 104 patients with occupational chronic mercury poisoning. The data on age, type of work, working years of mercury exposure, and past medical history were collected, and peripheral nervous conduction velocity and its correlation with age, working years of mercury exposure, and urinary mercury concentration were analyzed. Results: All the 104 patients with occupational chronic mercury poisoning had a mean of 45.37±9.82 years, median ( P (25), P (75)) working years of 7 (3, 11) , and a median ( P (25), P (75)) urinary mercury concentration of 88.50 (56.25, 163.03) μg/g Cr. The major clinical manifestations of peripheral nerve injuries were numbness of extremities (20.2%) , hypopselaphesia/hypalgesia or hyperpselaphesia/hyperalgesia (9.6%) , and bone/muscle pain in the extremities (6.7%) . Neural electromyography showed an increase in denervation potential (fibrillation potential or positive sharp wave) and a detection rate of abnormal peripheral nervous conduction velocity as high as 65.4%. The patients with an older age and more working years had a higher incidence rate of abnormal sensory conduction velocity of the ulnar nerve. There were significant reductions in motor and sensory conduction velocities of the median nerve, motor and sensory conduction velocities of the ulnar nerve, motor conduction velocity of the common peroneal nerve, and the sensory conduction velocity of the superficial peroneal nerve ( P <0.05) , with the increase in urinary mercury concentration. Conclusion: Patients with occupational mercury poisoning have a high rate of abnormal neural electromyographic findings, which can be used as an important method for early identification of chronic peripheral nerve injuries induced by mercury poisoning. The degree of peripheral nerve injuries increases with the increasing time of mercury exposure and urinary mercury concentration.