Trichloropropane and dichlorohydrin associated with painful peripheral neurotoxicity

Trichloropropane (TCP) and dichlorohydrin are widely used in industrial production; however, TCP and dichlorohydrin poisoning are rarely encountered in clinical practice. There have been no cases of peripheral neurotoxicity previously reported. A cluster of 23 patients who had been exposed to high levels of TCP and dichlorohydrin presented with painful peripheral neuropathy, and the pain was assessed using a visual analogue scale (VAS). Nerve conduction studies (NCS) were performed in all patients. All patients demonstrated symmetrical pin-prick pain in a stocking distribution in the lower limbs, with VAS scores between 3 and 10, with an average score of 6.8. NCS showed a mild mixture of axonal and demyelinating sensorimotor polyneuropathy in 14 of the 23 patients. After administration of standard neuropathic pain medication, pain was relieved in most patients. Painful peripheral neuropathy was the primary symptom observed in our patients, which differs from clinical and animal model reports of TCP or dichlorohydrin poisoning. However, the pathogenesis remains unidentified. TCP may be added to the list of industrial products that are toxic to the peripheral sensory nerves.