Hydrogen sulphide: mechanism of toxic action, clinical manifestations of acute poisoning, pathohistological signs and treatment strategy

Hydrogen sulphide (H2S) is a highly toxic gas. Among this group of poisonous substances – causes of death – it is second only to carbon monoxide. The mechanism of its toxicity has not been sufficiently studied and there is currently no specific antidote therapy. This gas is a high-priority chemical threat in industry, as well as a potential terrorist weapon of mass destruction, especially in wartime. Aim. Based on literary data and own researches, to summarize the current concepts of its toxicity mechanisms, clinical manifestations, treatment strategies and pathohistological signs of acute hydrogen sulphide poisoning. Materials and Мethods. Open sources of public information and scientific literature on the research topic were analysed. An analytical review of the publications of scientific online libraries PubMed, Medline, Elsevier was carried out. A retrospective analysis of the medical documentation of two cases with acute poisoning with H2S in combination with other toxic gases was carried out. The first case of acute poisoning with H2S and other sewage gases is in a patient who died in the conditions of a medical institution in the Kyiv region, who fell ill after a 15-minute stay in a household sewage septic tank. In the victim, the data of sectional and microscopic studies of lung tissue were also studied. The second case of acute H2S poisoning in combination with other gases of putrefaction is represented by three victims hospitalized at the clinic of the Research Centre of Preventive Toxicology, Food and Chemical Safety named after L.I. Medved, Ministry of Healthcare of Ukraine after cleaning a deep tank with the remains of rotten sauerkraut. One of the victims died after 6 hours. The methods of system comparative and content analysis were applied. Results. Modern ideas about the mechanism of the toxic effect of H2S indicate that it is a rapidly metabolizing systemic toxicant that affects mitochondria, is the basis for the formation of tissue hypoxia, activation of oxidative stress, inflammatory reactions, and apoptosis. Under the acute effects of H2S, the main target organs are the nervous, bronchopulmonary and cardiovascular systems. Until now, there are no specific antidotes for the treatment of H2S poisoning, so it includes oxygen, symptomatic and supportive therapy. New therapeutic agents – potential antidotes are at the stage of preclinical research, most of which are aimed at binding H2S. There is an urgent need for the development of new therapeutic agents – absorbents (scavengers) of H2S for the prevention and treatment of poisoning, reducing morbidity and mortality. Keywords: hydrogen sulphide, toxicity, acute poisoning, treatment, pathohistological signs.