A fatal case of potassium gold cyanide poisoning

A 77-year-old professional gold craftsman ingested a white powder used in goldsmithing, mistaking the powder for a health supplement. He detected a strange taste and immediately fell sick, reported the incident to 911, and was taken to the emergency room. He died approximately 8.5 h post-ingestion despite treatment. There were no significant findings in the autopsy, the victim's heart blood sample, gastric contents, and the white powder the victim had taken were submitted to the department of forensic toxicology. Using scanning electron microscopy energy dispersive X-ray analysis, potassium and gold (Au) were detected in the white powder. Ion chromatography analysis detected cyanide. Concentrations of cyanide were 0.5 mg/L in heart blood and 13.3 mg/L in gastric contents. Qualitative and quantitative analyses of Au in the heart blood sample and gastric contents using inductively coupled plasma-optical emission spectrometry detected concentrations of 79.8 mg/L and 2010.1 mg/L, respectively. Au and cyanide synergistically enhance cytotoxicity through inhibition of detoxification and increasing intracellular accumulation. In the present case, the detected blood cyanide concentration was sub or minimally lethal, and the blood Au concentration was high. The cause of the victim's death was the combined toxicity of Au and cyanide.