Alcohol and forensic pathology. Systematic reviews of literature, analysis of casuistries and of bizarre fatal cases in Friuli

In forensic practice, ethanol is by far the most detected drug in toxicological laboratories and the determination of its blood concentration (BAC) has important criminal and civil implications. However, postmortem BAC interpretation may be problematic, because of possible changes due to post-mortem artifacts. A method to differentiate the source of ethanol in post-mortem blood samples is the analysis of alcohols levels in alternative-to-blood specimens (e.g. vitreous humour or urine). Two different research lines were the object of this thesis: 1) to perform a retrospective analysis of necroscopic records of four specific types of deaths occurred in Friuli throughout the period 1993-2020: homicide-suicides (10 perpetrators and 13 victims), complex suicides (n=24), fire- (n=39) and water-related-deaths (n=69). The role of ethanol in these specific contexts was investigated through a review of the literature and unusual cases were separately discussed; 2) to analyse the relationship between alcohol levels detected in the synovial fluid and those detected in blood and in urine, in order to evaluate the potential role of this biological fluid as an alternative-to-blood specimen in post-mortem ethanol interpretation. Alcohol was the most detected drug in our case series and in literature: it resulted to have a neglegible influence on perpetrators of homicide-suicides (2/6 assailants with BACs of 0.21 and 0.25 g/L) and a significant role in the other types of death (BACs>0.5 g/L were detected in 3/6 victims of homicide-suicides, 5/20 fire-deaths and 6/11 complex suicides and a state of acute ethanol intoxication was noted in 22/40 water-related deaths). Literature review showed that medico-legal aspects of alcohol have been investigated in many studies, but little research has been done on some peculiar issues such as post-mortem alcohol interpretation in burned and submerged bodies, with a need, therefore, to improve the current state of knowledge of these topics. Weak agreements were observed between alcohol concentration of blood and synovial fluid (r=0.60, n=16) and urine and synovial alcohol (r=0.78, n=10). When it was possible to differentiate individuals in relationship to the stage of alcohol metabolism in which the death occurred, a strong agreement was observed in individual deceased during the post-absorption phase (both blood/synovial fluid and urine/synovial fluid: r=0.99, n=5) and a weak agreement in individuals deceased during the absorption phase (blood/synovial fluid: r=0.56 and urine/synovial fluid: r=0.61, both n=4). However, the research was carried out on a small sample and it is necessary to corroborate these preliminary results.