Motor neuron disorder simulating ALS induced by chronic inhalation of pyrethroid insecticides

Abstract

Some agricultural chemicals are known to be neurotoxic. Pyrethroid insecticides are commonly used as they are highly toxic to a wide range of insects but have low toxicity to mammals. However, overexposure to pyrethroids can induce various neurotoxic symptoms such as numbness, seizure, tremor, and memory impairment.1 Such symptoms are usually transient, and there are no reports indicating that chronic intoxication from pyrethroid insecticides causes motor neuron damage, although a case of pathologically proven motor neuron death after acute massive ingestion of pesticides containing pyrethroids and organochlorine has been reported.2 Here, we report a case of slowly progressive motor neuron disease (MND) following chronic exposure to pyrethroids that was indistinguishable from ALS. A 44-year-old woman, a food shop proprietor, had been using cans of pyrethroid insecticides containing imiprothrin, phenotorin, d-T80-resmethrin, and d-T80-phthalthrin almost every day for 3 years in an unventilated room. Initially, she experienced tongue numbness, nausea, and rhinitis while using …