Cardiovascular Magnetic Resonance in the Identification of Extra-Cardiac Causes of Myocarditis: a case series

Abstract

Myocarditis is challenging to diagnose due to its varied presentations. Endomyocardial biopsy is the gold standard for diagnosis, but its invasive nature has led to alternative non-invasive modalities, notably Cardiovascular Magnetic Resonance (CMR). Identifying the precise etiology of myocarditis is crucial for effective treatment, yet extra-cardiac causes are often overlooked. In this paper, we spotlight the underexplored role of CMR in diagnosing extra-cardiac etiologies, utilizing three insightful cases for illustration. The first case is a 31-year-old patient with myocarditis secondary to a pyogenic liver abscess, identified through CMR who improved after abscess drainage. The second case involves a 54-year-old patient with myocarditis attributed to adult T-cell leukemia-lymphoma, with the loco-regional thickening process identified thanks to CMR. This patient had an unfavorable disease progression due to the underlying malignancy. The third case concerns a 23-year-old patient suffering from myocarditis due to pneumonia, again illustrated effectively through CMR imaging and who recovered after antibiotic treatment. These cases underline the overlooked potential of CMR in diagnosing extra-cardiac etiologies of myocarditis, even though such causes are rare. Despite current guidelines recognizing the importance of identifying the etiology of myocarditis, they do not explicitly address the role of CMR in diagnosing extra-cardiac etiologies. Therefore, this article proposes that future guidelines could emphasize the utility of CMR in exploring these causes, potentially leading to more accurate diagnoses and improving patient outcomes. It also advocates for a comprehensive, multidisciplinary approach to myocarditis diagnosis, encouraging vigilance for potential loco-regional causes, and calls for further research in this area.