An autopsy case of sodium nitrite-induced methemoglobinemia with various post-mortem analyses

The use of sodium nitrite in suicide has become more common among young adults in the Republic of Korea. This report details the case of a 28-year-old man; the man had posted on a social network service detailing his attempt at suicide at 13:45. In the posted article, he stated that he had ingested 84 g of sodium nitrite. A post-mortem (PM) inspection was performed at 21:00, and peripheral blood (PB) was collected. An autopsy was performed approximately 44 h after death. The victim's face was dark brown in color, but the color of his oral mucosa was bright red. Toxicological analyses revealed 33% and 26% methemoglobinemia in the PB collected during PM inspection and autopsy, respectively. The concentration of nitrate in the PB collected during PM inspection, and PB and cardiac blood collected during the autopsy were 220.6 mg/L, 220.0 mg/L, and 218.5 mg/L, respectively. Nitrate was also detected in the pericardial fluid and cerebrospinal fluid at levels of 91.7 mg/L and 50.5 mg/L, respectively. The cause of death was determined to be methemoglobinemia-induced hypoxia due to sodium nitrite ingestion. This intoxication case informs some novel points about nitrite intoxication; the concentration of methemoglobin decreased during the PM period, while the concentration of nitrate was stable. There was no difference in the concentration of nitrate between cardiac and peripheral blood. Nitrate could be detected in the pericardial fluid and cerebrospinal fluid. This new information is helpful for better identifying future cases of nitrite intoxication.