Objective. To determine the main causes and pathomorphological characteristic of extra- and intracranial vessel pathological changes in young adults in the aspect of sudden death (SD) Material and methods. The authors investigated 10485 SD cases in young adults in the period from 2012 to 2016 (5 years) according to Moscow coroner bureau autopsy data. Morphological, chemical, histological, histochemical methods (staining with hematoxylin and eosin, van Gieson’s stain, Masson’s trichrome stain) were used. Results. Sudden death events of young adults are up to 11.93% of all non-violent death cases (81.18% of males, 18.81% — females). The mean age of the male group was 24.6, the female group 29.1. Intracranial vessel pathology was found in 549 cases (5%). Inborn aneurysms were identified as follows: arterial (69%), arteriovenous (26%) and arteriovenous malformations not diagnosed during lifetime (5%). In 14% of cases, ruptured aneurysms were combined with small extracranial ones on the convexital brain surface that show no signs of impairment. Histological investigation of aneurysms of any localization demonstrated the absence of multilayered vessel wall structure — elastic compartment with signs of disorganization, twists or total connective tissue replacement. In 93% of deaths caused by intracranial vessels rupture, the following signs of connective tissue dysplasia (CTD) were found: tall height, asthenic constitution, breastbone and cardiovascular pathology, mitral valve prolapse, aorta hypoplasia and so on. During the detailed vessel investigation in CTD group, a complex of pathological characteristics (total hypoplasia, wall thinning, S-form vertebro-basilar system vessels) was found. Conclusion. CTD is a pathology that becomes a risk factor for intracranial aneurysms formation and rupture in case of severe physical activity or emotional stress. Hemorrhagic infarct or non-traumatic subarachnoidal hemorrhage development lead to SD in young adults. Prompt CTD markers identification will provide new possibilities to prevent SD of youth.
