Reading between the troponin lines: acute myocarditis amid septic shock

Acute myocarditis (AM) is increasingly encountered in acute cardiac services, driven by improved detection with high-sensitivity troponin assays and wider availability of cardiac magnetic resonance (CMR). Distinguishing ‘true’ myocarditis from septic cardiomyopathy, acute coronary syndrome (ACS), and myocardial infarction with non-obstructive coronary arteries (MINOCA) remains a key clinical challenge with important implications for prognosis, management, and patient counselling.

Maher and colleagues reported a striking case of severe shigellosis with multi-organ failure and a rare cardiac manifestation consistent with AM. Acute chest pain, dynamic ECG changes, and elevated troponin suggested myocardial infarction. After CT coronary angiography (CTCA) excluded obstructive disease, attention shifted to alternative causes of myocardial injury. CMR proved decisive, providing tissue characterization consistent with AM and allowing confident distinction from infarction and sepsis-related myocardial dysfunction.

This case highlights that AM remains an important differential whenever troponin elevation and ECG changes occur during systemic inflammation or sepsis. It also illustrates the need to adapt guidelines to haemodynamic instability and competing diagnoses. Figure 1 outlines a practical diagnostic approach, reflecting recommendations in the 2025 ESC guidelines for myocarditis and pericarditis.