Pathological and toxicological findings in four cases of fatal hydrogen sulfide inhalation

Recently in Japan, there have been scattered cases of suicide by inhalation of hydrogen sulfide (H₂S), produced by mixing domestic chemicals containing sulfur and hydrochloric acid. We report four cases of such fatalities with regard to the pathological and toxicological findings. Two cases were male and female suicide victims (cases 1 and 2; about 2 days and 30 h postmortem, respectively), and the other two were a female suicide victim and her husband (cases 3 and 4; about 3 days postmortem). Partial greenish discoloration was observed on the skin in three cases (cases 1, 3, and 4), and also in the airways and lungs and on the brain surface in one case (case 3). The most evident pathology was marked pulmonary and cerebral edema in all cases. Concentrations of H₂S and the metabolite thiosulfate (TS) in the blood varied by case (0.66–85.0 and 0.00–369 μg/ml, respectively), and similar distributions were seen in the viscera; these concentrations were markedly high in a case of visceral discoloration (case 3). Both H₂S and TS contents in the skin and muscle were higher at the sites of discoloration in individual cases. A control study demonstrated an unexpected increase of TS contents along with H₂S production due to putrefaction as well as higher TS content than H₂S. It was difficult to discriminate putrefaction using H₂S and TS measurements, especially in gastric contents, bone marrow, heart, liver, kidney, spleen, pancreas, and intestine. However, vitreous body, pericardial fluid, and lung tissue showed different findings compared with putrefactive changes, and may be used as supplementary or alternative samples. These findings suggest the significant contribution of postmortem exposure to H₂S gas to the pathological and toxicological findings, depending on the circumstances, and the importance of systemic toxicological analysis for determining death due to H₂S intoxication.