Clinically Suspected Amitraz Poisoning Complicated by Acute Respiratory Failure and Toxic Encephalopathy: A Case Report

Abstract

Background: Amitraz is a formamidine insecticide and acaricide whose acute toxicity can cause profound central nervous system depression, autonomic disturbances, and respiratory compromise. Its clinical presentation may resemble organophosphate poisoning. Case Presentation: A 40-year-old man was admitted to a tertiary emergency department approximately 21 hours and 27 minutes after the reported intentional ingestion of amitraz. He had previously undergone induced emesis and had received intravenous atropine at referring facilities. On arrival, the Glasgow Coma Scale score was 6/15 (E2V1M3), respiratory rate was 36 breaths/min, and the recorded room-air peripheral oxygen saturation was 36%. The initial reported blood gas showed pH 7.16, PCO₂ 38 mmHg, and bicarbonate 13.5 mmol/L. Endotracheal intubation and mechanical ventilation were undertaken, with the recorded oxygen saturation subsequently reaching 95%. Intravenous fluids, a noradrenaline infusion, and other inpatient treatments were administered. The patient was extubated on the second hospital day and discharged after six days, and psychiatric follow-up was advised. Discussion: The initial gas values suggest metabolic acidosis with a possible additional respiratory component, whereas later gas measurements indicate unresolved acid–base complexity. Oxygenation measurements obtained without sampling and oxygen-delivery context cannot be fully reconciled. Conclusion: This case illustrates the importance of timely airway support and close physiological monitoring in severe clinically suspected amitraz poisoning while emphasising the limits of causal inference from a single case.