Human Poisoning with Chlorpyrifos and Cypermethrin Pesticide Mixture: Assessment of Clinical Outcome of Cases Admitted in a Tertiary Care Hospital in Taiwan

Yi-Jan Wu,1,2 Shu-Sen Chang,3 Hsien-Yi Chen,4 Kai-Fan Tsai,2,5 Wen-Chin Lee,2,5 I-Kuan Wang,6,7 Chern-Horng Lee,8 Chao-Yu Chen,1,2 Shou-Hsuan Liu,1,2 Cheng-Hao Weng,1,2 Wen-Hung Huang,1,2 Ching-Wei Hsu,1,2 Tzung-Hai Yen1,2 1Department of Nephrology, Clinical Poison Center, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan City, Taiwan; 2College of Medicine, Chang Gung University, Taoyuan City, Taiwan; 3Institute of Health Behaviors and Community Sciences, Department of Public Health, College of Public Health, National Taiwan University, Taipei City, Taiwan; 4Department of Emergency Medicine, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan City, Taiwan; 5Division of Nephrology, Department of Internal Medicine, Chang Gung Memorial Hospital, Kaohsiung Branch, Kaohsiung City, Taiwan; 6Department of Nephrology, China Medical University Hospital, Taichung City, Taiwan; 7College of Medicine, China Medical University, Taichung City, Taiwan; 8Division of General Internal Medicine and Geriatrics, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan City, TaiwanCorrespondence: Tzung-Hai Yen, Department of Nephrology, Clinical Poison Center, Chang Gung Memorial Hospital, Linkou Branch, 5 Fu-Hsing Street, Kweishan, Taoyuan City, Taiwan, Tel +886 3 3281200 ext 8181, Fax +886 3 3282173, Email m19570@cgmh.org.twBackground and Purpose: There is an overall paucity of data regarding the human toxicity of chlorpyrifos and cypermethrin pesticide mixture. Both organophosphate and pyrethroid insecticides are metabolized by carboxylesterases. Thus, its pesticide combination, organophosphates may boost the toxicity of pyrethroids via inhibited its detoxification by carboxylesterases. This study examined the clinical course, laboratory tests, and outcomes of patients with chlorpyrifos, cypermethrin or their pesticide mixture poisoning, and to determine what association, if any, might exist between these findings.Patients and Methods: Between 2000 and 2021, 121 patients poisoned with chlorpyrifos, cypermethrin, or their pesticide mixture were treated at Chang Gung Memorial Hospital. Patients were categorized as chlorpyrifos (n=82), cypermethrin (n=27) or chlorpyrifos and cypermethrin (n=12) groups. Demographic, clinical, laboratory and mortality data were collected for analysis.Results: The patients experienced a broad range of clinical symptoms, including aspiration pneumonia (44.6%), salivation (42.5%), acute respiratory failure (41.3%), acute kidney injury (13.9%), seizures (7.5%), hypotension (2.6%), etc. Leukocytosis (12,700± 6600 /uL) and elevated serum C-reactive protein level (36.8± 50.4 mg/L) were common. The acute respiratory failure rate was 41.3%, comprising 48.8% in chlorpyrifos, 11.1% in cypermethrin as well as 58.3% in chlorpyrifos and cypermethrin poisoning. Patients with chlorpyrifos and cypermethrin pesticide mixture poisoning suffered higher rates of acute respiratory failure (P=0.001) and salivation (P=0.001), but lower Glasgow Coma Scale score (P=0.011) and serum cholinesterase level (P< 0.001) than other groups. A total of 17 (14.0%) patients expired. The mortality rate was 14.0%, including 17.1% in chlorpyrifos, 3.7% in cypermethrin as well as 16.7% in chlorpyrifos and cypermethrin poisoning. No significant differences in mortality rate were noted (P=0.214).Conclusion: Chlorpyrifos pesticide accounted for the major toxicity of the pesticide mixture. While the data show a higher rate of respiratory failure in the chlorpyrifos and cypermethrin pesticide mixture group than others, other measures of toxicity such as mortality and length of stay were not increased.Keywords: chlorpyrifos, cypermethrin, pesticide mixture, poisoning, acute respiratory failure, mortality