Intentional Large-Volume Diazinon Ingestion Complicated by Seizure and Acute Respiratory Failure: A Case Report

Organophosphate poisoning is a major cause of acute cholinergic toxicity and can progress rapidly to respiratory failure and death. In the emergency setting, diagnosis is often clinical, and treatment should not be delayed while awaiting confirmation of the specific compound. We report a case of a 30-year-old male patient who presented after intentional ingestion of a large reported volume of diazinon-containing pesticide. Within approximately 30 minutes of ingestion, he developed acute cholinergic manifestations, including bradypnea, bradycardia, hypotension, hypersalivation, vomiting, diarrhea, and depressed level of consciousness, complicated by a generalized tonic-clonic seizure. The seizure was treated with diazepam, and atropine was initiated before transfer to the emergency department. On arrival, the patient was in severe respiratory distress with profuse secretions and required urgent endotracheal intubation and mechanical ventilation. Empiric treatment for suspected organophosphate poisoning was continued with atropine and pralidoxime, alongside supportive care. Collateral history later identified the ingested product as Diacidol 600 Emulsifiable Concentrate, containing diazinon 600 g/L, equivalent to 60% weight/volume. Plasma butyrylcholinesterase, red blood cell acetylcholinesterase, and toxicological confirmation testing were not available at our institution at the time of evaluation, which represents a limitation of this report. The patient was admitted to the intensive care unit and managed with atropine and pralidoxime infusions, ventilatory support, and close monitoring for delayed neuromuscular complications. His cholinergic features resolved, and he was successfully extubated within 24 hours. Antidotal therapy was discontinued after sustained clinical improvement, and he remained stable during subsequent ward observation. This case emphasizes that severe organophosphate poisoning remains a clinical diagnosis during initial resuscitation. Early airway protection, titrated atropinization, pralidoxime therapy, benzodiazepines for seizures, and observation for delayed complications are central to favorable outcomes.