An Autopsy Case of Fatal Methemoglobinemia due to Ingestion of Sodium Nitrite

We herein present an autopsy case of fatal methemoglobinemia due to suicidal ingestion of sodium nitrite. A man in his 30s who had exhibited mild depression was found dead in his house. A glass containing a white turbid solution and a suicide note were found on the table near the decedent. At autopsy, the lividity of the face and back was greenish gray, and the blood was tinted a chocolate brown color. Toxicological analysis of nitrite and nitrate using a colorimetric method showed that the nitrite concentrations were <0.05 and 0.09 μg/mL and that the nitrate concentrations were 71.69 and 83.48 μg/mL in the heart and femoral blood, respectively. Biochemical analysis after death showed that the level of methemoglobin was 83.4% by spectrophotometry. We conclude that the cause of death was severe methemoglobinemia following acute poisoning induced by sodium nitrite ingestion, although the blood nitrite concentration did not reach the fatal level.