Clinical features and management of two fatal cases with suspected chlorfenapyr exposure presenting with different clinical phenotypes: a case report

Chlorfenapyr is a broad‑spectrum insecticide and acaricide that exerts potent gastrointestinal and contact toxic effects against target pests. Acute chlorfenapyr poisoning has an insidious onset with nonspecific early clinical manifestations, making early diagnosis challenging. We report two cases with suspected chlorfenapyr exposure admitted to our hospital presenting with unexplained disturbance of consciousness and acute myocardial infarction, respectively. Both cases were male and Han Chinese. The first patient, 35-years-old, presenting with consciousness disturbance, was found to have insecticide in his pocket and regained consciousness on Day 2 following treatment. On Day 3, he developed profuse diaphoresis, followed by persistent high fever and shallow coma on Day 4. He ultimately succumbed in a state of rigor mortis at 16:41 on Day 4. The second patient, 65 years old, initially presenting with myocardial infarction, was then taken a toxicological test three hours post-admission, shortly before his death. Although toxicological test verified chlorfenapyr exposure after admission, causal attribution remained ambiguous. Both patients developed high fever, profuse sweating, tachypnea, and altered mental status on the day of death, ultimately succumbing to cardiorespiratory arrest in a state of rigor mortis. Suspected chlorfenapyr exposure represents one probable factor contributing to their fatal clinical course. This study summarizes key clinical lessons from these two cases and the existing literature, aiming to enhance understanding of early clinical signatures of chlorfenapyr poisoning and provide a foundation for future clinical research.