Case Report: Serial blood benzene and urinary phenol monitoring during extracorporeal treatment after severe acute oral ingestion of a benzene-containing solvent.

Background: Acute oral benzene poisoning is uncommon, and evidence to guide extracorporeal treatment and bedside toxicokinetic interpretation in this setting is limited. Most published experience concerns inhalational exposure or chronic hematotoxicity, leaving clinicians with little practical guidance for managing large intentional ingestions. Case Report: An 18-year-old man presented approximately 12 h after ingesting about 200 mL of a commercial benzene standard solution in ethyl acetate as intentional self-poisoning. On admission he had tachycardia, persistent gastrointestinal symptoms, and laboratory confirmation of exposure, with benzene detected in gastric fluid (2,966 μg/L), blood (457 μg/L), and urine (224 μg/L). Before gastric lavage, toxicological confirmation was obtained in all three matrices. After decontamination and supportive care, sequential hemoperfusion and continuous veno-venous hemodiafiltration (CVVHDF) were initiated. Serial toxicological monitoring showed rapid decline of the parent compound-blood benzene decreased to 228 μg/L at 20 h, 78 μg/L at 28 h, and became undetectable by 32 h-whereas urinary phenol rose later, peaking at 3231.5 mg/L at 32 h before declining over subsequent days. The clinical course included rhabdomyolysis, transient liver injury, erosive gastritis, and transient nonspecific white-matter abnormalities on brain magnetic resonance imaging (MRI). The patient recovered without persistent neurologic deficit and returned to usual activities. Conclusion: In severe acute oral ingestion of a benzene-containing solvent, paired monitoring of the parent compound and a major metabolite provided clinically useful information to contextualize extracorporeal treatment when formal decision thresholds were unavailable. This case cannot establish treatment efficacy, but it illustrates a pragmatic monitoring framework that may assist clinicians interpreting late toxicokinetic trends in rare but high-risk solvent ingestions.