Suicidal sodium azide intoxication: An analytical challenge based on a rare case

Intentional absorption of sodium azide is exceptional but remains extremely life-threatening because death rapidly occurs when significant doses are absorbed, either due to the direct effect of sodium azide or an indirect effect due to nitric oxide, cyanide ions or hydrazoic acid production from sodium azide.

The body of a laboratory assistant, was discovered by his colleagues in the laboratory, seated on a chair located near a digital computer displaying information about sodium azide. Moreover, a half empty 99% sodium azide flask was found near the corpse. The laboratory staff confirmed that the young man was still alive 5h prior to discovery.

Postmortem examination did not show any cutaneous signs of injury due to a defensive struggle. Bilateral ungual cyanosis was observed as well as a major cerebral edema and visceral congestion on autopsy. The elevated sodium azide concentration found in the gastric sample and the amount of gastric content allowed to conclude that sodium azide intake was more than 6g which was above the lethal dose, i.e. approximately 1g. Surprisingly, no sodium azide was found either in blood and serum, or in hepatic and renal tissue samplings. However, major concentrations were observed in the gastric contents, bile and urinary samples, as well as in cardiac and cerebral tissues samples. No other toxic element was found. Therefore, the post-mortem findings, the autopsy and the analytical results suggested that the laboratory assistant died after an intentional sodium azide ingestion.

Sodium azide poisoning by ingestion has to date remained extremely rare and our case highlights the extreme lability of sodium azide as it was absent in the blood, in spite of significant concentrations in stomach content and some tissues. Therefore, the necessity of multiple tissues samples during autopsy should be underlined.