HISTOPATHOLOGY OF DRUG ABUSE: A RETROSPECTIVE STUDY ON 312 CASES

The aim of the present study is to evaluate the postmortem histopathologic pattern in drug abusers retrospectively analyzing the records of two Institutes of Legal Medicine and two adjoining countries. The use of exogenous substances, both illicit and lawful, for recreational purposes is widely diffused and the effects of drugs can be observed in both surgical pathology and in forensic practice, as is often cause of death by itself or associated to other diseases. Multiple drugs intoxication or abuse is also a great issue for the forensic pathologist, because in such cases it is difficult to understand the effects of each substance. This retrospective research focuses, above all, on cardiac and encephalic alterations due to both illegal drugs (the most of which were heroin and cocaine) and lawful substances (benzodiazepines, barbiturate, etc.) and on the relationship between the kind of substance, the cause of death and the histopathologic findings. The study included 312 cases of exogenous substances intoxication which were autopsied between 1999 and 2015. The police and medical records, the autopsy report, the results of toxicological exams and the histology (on hematoxylin-eosin slides) were re-examined for each case. 32 cases were excluded because of too advanced putrefaction that hampered the histologic examination and the toxicological analysis. The whole series was classified into two groups: deaths due to drug intoxication (200) and deaths of drug abusers for other causes (80). The latter group included traumatic deaths, such as road accidents, homicides (mostly blunt force injuries and asphyxia), and suicides (fall from an height, hanging). The detected substances were arranged into illicit drugs (cocaine, synthetic stimulants, heroin, marijuana) and lawful substances (benzodiazepines, barbiturate, etc.), often associated with alcohol assumption. Overall, the most interesting microscopic alterations regarded the brain and heart. Concerning heart, fibrosis, both interstitial and perivascular, small vessels disease, with thickening and vasculitis, fragmentation of cardiomyocytes, atherosclerosis at a young age were detected. A broad spectrum of neuropathologic changes were encountered among both groups. The most frequent findings were vessel thickening, micro-hemorrhages, oedema and metabolic disorders. Differences between the two mentioned group were assessed, resulting a significant contrast. Then, histopathological findings were correlated with the kind of substance detected at toxicology (and/or known from circumstantial data and anamnesis), again with remarkable differences. The most frequent cardiac disorders reported in literature in drug abusers, including vasoconstriction of coronary arteries (inhibition of NO synthesis and stimulation of endothelin-1 release) and decreased blood flow to the myocardium; alteration of coagulation (platelet function); endothelial dysfunction (induction of von Willebrand factor in endothelial cells) and prothrombotic state were consistent with the present findings. Regarding neuropathologic pattern, oedema, vascular congestion, ischaemic nerve cell damage and neuronal loss were always found but are not specific. In the light of this study, the need of further research is particularly felt in the field of neuropathology.