Features of Myocarditis: Morphological Differential Diagnosis in Post-COVID-19 Children

Abstract

Myocarditis is characterized by dysfunction and destruction of cardiomyocytes, infiltrative inflammation, and development of fibrosis. Late diagnosis of myocarditis has been a serious global health problem, especially due to the spread of a new coronavirus infection. The aim of this review is to identify differences between myocarditis of viral etiology, including SARS-CoV-2 lesions, based on instrumental and pathomorphological findings. Material and Methods: We analyzed publications covering the period from December 2019 to May 2023, published in publicly accessible international databases (“Medline”, “PubMed”, “Scopus”), with queries for the keywords “myocarditis”, “children”, “cardiovascular inflammation”, “COVID-19”, “SARS-CoV-2”, “severe acute respiratory syndrome coronavirus 2”, “differential diagnosis”. Results: It was found that no unambiguous morphological criteria for the diagnosis of myocarditis coupled to SARS-CoV-2 lesions were identified. However, the detected histopathological changes such as virus-associated degeneration, apoptosis, cardiomyocyte necrosis, moderate interstitial hyperemia, myocardial tissue oedema, and capillary endothelial cell dysfunction were the major markers of SARS-CoV-2 infection. Conclusion: It is necessary further reconsider morphological criteria to diagnose SARS-CoV-2-caused myocarditis, rather than solely relying on detecting viral RNA by PCR as the sole evidence-based criterion. Similar issues accompany diagnostics of myocardial lesions associated with other viral infections. Evidence for an etiological diagnosis of myocarditis can be provided by a comprehensive analysis of the diagnostic criteria obtained, confirming virus exposure, followed by development of distinct clinical symptoms, MRI and CT changes, and morphological criteria.

Case Series of Mild Myocarditis: The Role of Speckle Tracking Echocardiography in Detecting a Patchy Disease

“…There is little or no knowledge of the specific tropism of influenza or adenovirus, before this case series, and two cases are not robust enough to suggest a specific tropism, but might be sight-opening to another advantage of STE, which is the determination of the specific tropism of viruses to certain regions of the cardiac muscle. [11]…”

Are Endomyocardial Ventricular Biopsies Useful for Assessing Myocardial Fibrosis?

“…Myocardial fibrosis is the most common pathologic process in cardiac tissue. It represents the final phase of tissue response to myocardial damage of any origin, whether due to pressure overload in the context of hypertension (HHD) or as a result of direct and/or mediated tissue damage in chronic myocarditis [ 1 ].…”