n-Hexane intoxication in a Chinese medicine pharmaceutical plant: a case report

n-Hexane is a well-known neurotoxicant. Polyneuropathy due to occupational n-hexane exposure has been reported worldwide, however, our case is the first report in the Chinese herb industry.

A 25-year-old Asian man experienced progressive weakness and numbness in his hands and feet after working as an operator in a Chinese medicine pharmaceutical plant for the manufacture of Chinese herbal pain relief patches for 10 months. Electrophysiological studies indicated a reduction in nerve conduction velocity, prolongation of distal latencies, mildly positive sharp waves, and reduced recruitment with polyphasic potentials, particularly at distal sites. Demyelination with axonal degeneration caused by occupational n-hexane exposure was strongly suspected. Through investigation of our patient's workplace, the ambient n-hexane concentration in air was found to considerably exceed the permissible exposure limit/time-weighted average for n-hexane in Taiwan. His symptoms were gradually relieved after 4 months of cessation of exposure to n-hexane. He was then confirmed as a case of occupational n-hexane intoxication. Further effective control measures should be implemented as soon as possible to prevent exposure of workers to n-hexane.

Despite a typical clinical presentation, his exposure at workplace was appropriately investigated. Chemical exposure in Chinese medicine pharmaceutical plants could be an emerging issue that may affect workers' health. The lack of knowledge and management of solvents could endanger the health of workers. This case has profound educational implications for occupational health and is worthy of further follow-up for improving hazards control.