A Case of Mixed Herbicide Poisoning Presenting with Diverse Findings: Diagnostic Pitfalls and the Importance of Psychosocial Context

Background: Although glyphosate-based herbicides are generally considered to have low acute toxicity to humans, commercially available formulations may contain multiple active ingredients and co-formulants that produce atypical clinical manifestations.Case Presentation: A 53-year-old woman with a history of panic disorder and kleptomania was found collapsed at home by her family just before incarceration. On arrival, she had marked bilateral mydriasis (8 mm), impaired consciousness (Glasgow Coma Scale: E1V1M1), QTc prolongation (633 ms), metabolic acidosis, and elevated lactate. Stimulant intoxication was initially considered because of mydriasis and a positive urine amphetamine screen; however, she lacked hypertension, tachycardia, diaphoresis, and agitation, and QT prolongation was not interpreted as evidence of adrenergic stimulation. Detailed history-taking and UPLC-HRMS toxicological analysis revealed ingestion of a commercial herbicide containing glyphosate isopropylamine salt, flumioxazin, and MCPA, with MCPA detected in serum. She improved with conservative treatment and was discharged on hospital day 8.Discussion: This case illustrates atypical toxicosis caused by a multi-ingredient herbicide. The presentation did not fulfill a classic sympathomimetic toxidrome; instead, mydriasis, impaired consciousness, QT prolongation, and ileus required broad differential diagnosis. Component-specific assessment suggested that glyphosate-surfactant exposure, MCPA toxicity, and uncertain co-formulant effects together contributed to the clinical picture. Quantitative pupillometry and confirmatory toxicological analysis helped avoid diagnostic anchoring.Conclusion: Commercial herbicide poisoning should not automatically be interpreted as single-agent glyphosate poisoning. Separating key clinical problems from formulation-specific toxicities may improve emergency diagnosis and management.