Journal of The Korean Society of Clinical Toxicology

Two Cases of Comatose Patients Presenting after Exposure to Hydrogen Sulfide Gas: Hyun-Ho Ryu, Byeong-Guk Lee, Kyung-Woon Jeung, Tag Heo, Yong-Il Min; J Korean Soc Clin Toxicol. 2009;7(1):26-31. Published online June 30, 2009

Abstract PDF: Hydrogen sulfide is a by-product of decayed organic material and is ubiquitously found as an ingredient of manufacturing reagents or as an undesirable by-product of the manufacturing or industrial processing. Hydrogen sulfide is a chemical asphyxiant and interferes with cytochrome oxidase and aerobic metabolism. It has thus been deemed an important cause of work-related sudden death. This gas is particularly insidious due to the unpredictability of its presence and concentration and its neurotoxicity at relatively low concentrations, causing olfactory nerve paralysis and loss of the warning odor. Here, we report two cases of comatose patients presenting after accidental exposure to hydrogen sulfide gas.

Chemical Asphyxiants - Cyanides and Hydrogen Sulfides: Yang Ho Kim, Young Hee Choi, Choong Ryeol Lee, Ji Ho Lee, Cheolln Yoo, Hun Lee; J Korean Soc Clin Toxicol. 2003;1(1):12-20. Published online June 30, 2003

Abstract PDF: Cyanides and hydrogen sulfide ($H_2S$) are major chemical asphyxiants. They have common mechanism of action which inhibit cellular respiration and induce histotoxic hypoxia. They do not generate ATP, and all processes dependent on ATP are stopped. No extraction of $O_2$ from blood decreases AV $O_2$ differences, and the shift to anaerobic glycolysis brings about lactic acidosis with high anion gap. The mainstay of the treatment is rapid treatment with appropriate use of antidotes. However, there are several differences between cyanides and $H_2S$. First, $H_2S$ is not metabolized by enzymes such as thiosulfate. Thus thiosulfate does not play any role in treatment of $H_2S$. Second, $H_2S$ is a more potent inhibitor of cytochrome aa3 than cyanide. Third, $H_2S$ induces more divergent neurologic sequele than cyanide. Finally, $H_2S$ is not absorbed via skin.

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