Lambda-cyhalothrin ingestion: an infrequent yet concerning presentation of pyrethroid poisoning

Lambda-cyhalothrin is a type II pyrethroid compound commonly used as a pesticide, with the potential to cause life-threatening toxicity in humans. Furthermore, among cases of pesticide poisoning in Nepal, organophosphates are most frequently implicated.

A 40-year-old female presented to our hospital after ingesting a pesticide compound with suicidal intent. She also admitted to alcohol intoxication and exhibited symptoms of confusion, abdominal pain, nausea, and vomiting. An atropine challenge test yielded negative results. Therefore, conservative management was continued. It was discovered later that the ingested pesticide was lambda-cyhalothrin. The patient's condition eventually improved with supportive treatment.

Several reports have highlighted the overlapping clinical features between organophosphorus and pyrethroid poisoning. In some cases of pyrethroid poisoning, misdiagnosis as organophosphorus poisoning has occurred, leading to the inappropriate administration of atropine. In our case, initial management was challenging owing to the lack of accurate information about the ingested compound. On further evaluation, cholinergic clinical features were absent and the atropine challenge test was negative. This was suggestive of nonorganophosphorus compound poisoning.

This case illustrates that managing pesticide poisoning becomes challenging when the nature of the pesticide is unknown. Patients suffering from poisoning caused by pyrethroid compounds like lambda-cyhalothrin can present with features resembling organophosphorus poisoning. In such circumstances, a comprehensive clinical evaluation should guide the management. Clinical features and an atropine challenge test can aid in differentiating organophosphorus from nonorganophosphorus compound poisoning. This distinction facilitates therapeutic decision-making, including the consideration of atropine administration.