A Narrative Overview of Fatal Myocarditis in Infant with Focus on Sudden Unexpected Death and Forensic Implications

Abstract

Myocarditis, an inflammatory disease of the myocardium, is increasingly recognized as a potential contributor to sudden infant death syndrome (SIDS), though often underdiagnosed. This study reviews the current literature on the association between myocarditis and sudden death in infants, with a focus on autopsy and histopathological findings. A comprehensive search of the PubMed database yielded 64 studies published between 1960 and 2024; after applying specific inclusion criteria-such as patient age (0-6 years), presence of autopsy data, and forensic investigation-40 studies were analyzed in detail. The review identified myocarditis-especially lymphocytic-as an underrecognized but critical cause of sudden death in infants and children. Histological, molecular, and immunohistochemical findings highlighted viral infections, immune dysregulation, and structural anomalies as frequent etiological factors. Several SIDS cases were reclassified as myocarditis upon in-depth examination. These findings underscore the value of standardized autopsy protocols and integrated diagnostic approaches. Advanced postmortem diagnostic techniques, including polymerase chain reaction (PCR) and immunohistochemistry, have enhanced the detection of viral myocarditis. In addition, structural cardiac anomalies, such as cardiomyopathies and coronary abnormalities, may co-exist and contribute to sudden cardiac death. These findings emphasize the need for standardized autopsy protocols and the integration of molecular diagnostics in forensic investigations of SIDS. Further research is essential to improve early detection, refine diagnostic criteria, and develop preventive strategies to reduce the incidence of sudden infant death related to myocarditis.

Keywords: autopsy findings; forensic pathology; lymphocytic myocarditis; myocarditis; pediatric sudden death; sudden infant death syndrome (SIDS).

Figure 1

Estimated distribution of identifiable causes in sudden infant death cases, based on data from retrospective autopsy-based studies.

Figure 2

Flow diagram about selection process.

Figure 3

Postmortem diagnostic workflow illustrating how complete autopsy, including histological and molecular analysis, enables the identification of myocarditis as a cause of death in cases initially classified as SIDS (source: Biorender.com).