Fenthion flea-killer: Unpredictable and dangerous

Abstract

Introduction This case of fenthion poisoning demonstrates the delayed, protracted and yet unpredictable nature of cholinergic effects which are unique to fenthion toxicity. Case Presentation A 36-year-old female presented to the emergency department with drowsiness and vomiting, 8 hours after an unknown pesticide ingestion. She had some cholinergic symptoms (miosis, incontinence, emesis) suspicious of organophosphate toxicity but was initially well with no bronchorrhea or bradycardia. During her admission, she developed increasing salivation and bronchorrhea resulting in respiratory failure requiring intubation 27 h’ post-ingestion. Possible aspiration pneumonitis was initially considered given the delayed nature of deterioration. However, blood toxicology results confirmed fenthion poisoning. Atropine and pralidoxime boluses were administered followed by continuous infusion. She was extubated after initial improvement and stabilization – only to require reintubation for recurring respiratory failure and seizures on Days 4 and 5, each time following apparent recovery. She was eventually weaned off mechanical ventilation only on Day 31. Discussion and Conclusion This case illustrates the importance of physician awareness to potentially innocuous presentations of fenthion poisoning as symptoms at the onset may appear benign and falsely reassuring. Serious toxic manifestations may be significantly delayed over a prolonged, waxing-and-waning clinical course because of the compound’s high lipid solubility and metabolism into potent secondary compounds.