Histomorphological Patterns in Myocarditis in Postmortem Specimens- A Descriptive Observational Study over a Period of 4 Years at a Tertiary Care Centre in Kerala

Abstract

BACKGROUND In cases of sudden death, myocarditis is not an unusual finding especially when communicable diseases of viral origin are on the rise. Detection of myocarditis poises a diagnostic challenge to clinicians due to the absence of specific symptoms and there is a possibility of this being masqueraded as myocardial infarction. Examination of autopsy specimens are of utmost importance to detect the underlying etiology. For diagnosis of myocarditis histopathological examination of cardiac tissue is the gold standard. This is carried out based on Dallas criteria. Aim-This study was done to assess the, gross and histopathology findings in myocarditis in post mortem specimens in a tertiary care hospital in Kerala over a span of 4 years. METHODS This is a descriptive observational study. All cases of Myocarditis diagnosed in the Department of Pathology, Medical College, Kottayam during the period of 4 years from January 2012 to December 2015 were included. Age distribution, gross and histopathologic findings were studied using the registers, post mortem specimens and histopathology slides in the department. Immunohistochemical studies were done in paraffin blocks of all newly diagnosed cases of myocarditis and some previously diagnosed cases the data was analyzed using SPSS. RESULTS We received a total of 82 cases of myocarditis. The age distribution ranged from 75 days to 83 years. There was greater predilection for males accounting for 62% of cases. Inflammation was found in all cases and the predominant inflammatory cells were lymphocytes seen in 73% of cases. Myocyte necrosis was found in majority of the cases (98%). CONCLUSIONS Myocarditis was found to be an important cause of sudden death accounting for 0.15%.The age group affected was more in the 3 rd and 4 th decade,which was comparable with other similar studies. Viral myocarditis constituted the majority of cases and mononuclear inflammation was seen in myocardium. Myocarditis was seen as part of systemic inflammation in 70% of cases. Application of Dallas criteria was helpful in diagnosis but correlation with clinical details and meticulous examination of coronaries are also needed to exclude conditions which may mimic myocarditis.