A Mixture of Organophosphate and Pyrethroid Intoxication Requiring Intensive Care Unit Admission: A Diagnostic Dilemma and Therapeutic Approach

In Brief The illegal mixing of organophosphates and pyrethroids in marketed agriculture insecticides is becoming prevalent in developing countries. Over a 12-mo period, 8 patients were admitted to the emergency department of a university hospital in Dharan, Nepal after ingestion of such a mixture with suicidal intent. All patients presented with a combination of miosis, bradycardia, tachypnea, and unconsciousness. The occurrence of both pupillary dilation after a small-dose infusion of atropine (0.08 to 0.2 mg/kg in 1–3 h) and seizures raised the possibility of pyrethroid poisoning. In each case, an examination of the insecticide container confirmed that it contained a mixture of organophosphate and pyrethroid. After seizure control, gastric lavage, respiratory support, hemodynamic stabilization and diuresis, seven of the patients recovered without neurological deficit. One patient suffered aspiration pneumonia and died. The early clinical picture after this mixed poisoning is based on the toxicity of organophosphates rather than pyrethroids. Because the patients responded to a small dose of atropine with mydriasis and tachycardia, it suggested a mixed poisoning. Early suspicion of mixed poisoning may have a significant prognostic impact. IMPLICATIONS: The clinical presentation of acute poisoning resulting from the ingestion of an insecticide containing an unauthorized mixture of organophosphate and pyrethroid is similar to that of organophosphate alone. The ingestion of such a mixture may cause significant diagnostic difficulty and jeopardize the safety profile (complete elimination from mammals with little tissue accumulation) of the pyrethroid group of insecticides.