Multi-organ involvement as a pathogenetic principle of the radiation syndromes: a study involving 110 case histories documented in SEARCH and classified as the bases of haematopoietic indicators of effect

Abstract

The purpose of this contribution is to analyse the extent and severity of radiation-induced multi-organ involvement (MOI) and multi-organ failure (MOF) following whole body exposure to ionising radiation in 110 patients who were involved in different radiation accidents that occurred between 1945 and 2000. The clinical case histories were documented systematically in SEARCH (System for Evaluation and Archiving of Radiation Accidents based on Case Histories), which was established by our group in collaboration with international experts. The consequences of radiation-induced MOI in these patients were examined for two severity-of-response categories. On the basis of early (days 1–10 following exposure) haematological signs and symptoms, 45 of the patients could be assigned to response category (RC) 4; 65 patients presented early haematological changes characteristic for RC 3. All patients assigned to RC 4 died within 60 days, whilst the patients in RC 3 survived the first 100 days owing to an autologous haematopoietic recovery as well as necessary recovery of other organ systems. All of the 45 patients assigned to RC 4 suffered from the consequences of haematological, gastrointestinal, skin and neurovascular involvement. Regarding other organ systems in these 45 patients in RC 4, 20 patients showed evidence of cardiovascular involvement, 32 showed respiratory involvement, 25 showed liver involvement and 32 showed urogenital involvement. The patients assigned to RC 3 also displayed MOI, but at a significantly lower level. All of them showed signs and symptoms of involvement of haematopoiesis, the gastrointestinal system, skin and the neurovascular system. However, in contrast to the RC 4 patients, the RC 3 patients were reported to have less severe impairments of the cardiovascular, respiratory, metabolic and urogenital systems. It also became clear that the symptomatology of organ system involvement could be traced not only to the pathophysiology of the rapidly turning over cell renewal systems but — of equal or more importance — to the vascular system and specifically, to the endothelial components. Thus, it will be a challenge of further research to consider the cellular and molecular mechanisms involved in radiation-induced MOI and MOF. Necessary therapeutic measures should be determined on an improved pathophysiological basis.