Prolonged cholinergic toxidrome with markedly low cholinesterase activity after exposure to emamectin benzoate emulsion: A case report

Emamectin benzoate emulsion is a macrocyclic lactone insecticide that is not classified as an organophosphate or carbamate. We report the case of a man in his 80s with chronic kidney disease and cardiovascular comorbidities who ingested emamectin benzoate emulsion. On day 2, he presented with abdominal pain, diarrhea, and marked sialorrhea; his vital signs were stable; however, his serum cholinesterase (ChE) had markedly declined (18 U/L). The patient was discharged with supportive care. From day 3, watery diarrhea recurred and neurobehavioral symptoms progressed. On day 5, he presented with pinhole miosis and further ChE suppression (2 U/L). Therefore, atropine was administered, and the patient was transferred for close monitoring. After discharge (day 8), miosis and sialorrhea persisted, and ChE remained low for weeks. Findings suggestive of tubular injury were observed during follow-up. The patients' symptoms resolved gradually, with ChE partially recovering by days 75 - 95. This case underscores the need for serial reassessment and structured follow-up after pesticide exposure, even when the patient appears stable at the initial presentation.