Forensic grading of myocarditis: an experimental contribution to the distinction between lethal myocarditis and incidental myocarditis.

Myocarditis can be either the cause of the death of a person or just an incidental finding during the autopsy and the following histological examinations. To establish whether a single myocarditis is a lethal or just an incidental pathology a very careful grading is always mandatory. The aim of the present work is thus to test the hypothesis about the reliability of an evidence-based distinction between the lethal myocarditis and the incidental myocarditis. The present work compares clinical and histological features from two different groups of myocarditis. Group A is composed of patients having myocarditis at the time of death, who certainly died from other reasons (i.e.: death by head gunshot with no survival time). Group B is composed of patients who died having a myocarditis as the only pathological evidence at the autopsy and the following histological and toxicological examinations and then who died because of the myocarditis. The lethal myocarditis and the incidental myocarditis differ statistically about last days' anamnesis, acute findings in the macroscopic analysis of the heart, neutrophilic infiltration, myocite necrosis, multiple sites interstitial oedema and perivascular cuffs. Such variables can be summarized in a scoring system able to quantitatively separate the lethal myocarditis from the incidental myocarditis. Such a reliable scoring system develops far behind the isolated grading of the myocite necrosis, even though the myocite necrosis should always be considered as a pivot variable for distinguishing lethal myocarditis from incidental myocarditis. The proposed scoring system is very easy to use and it is also appreciably money-sparing with its foundations in the simple combination of clinical anamnesis, autopsy and basic histology. Its routinary application could implement the objectivity in the forensic grading of myocarditis.