Diphteric Myocarditis: A Case Report on Ecg and Cardiac Imaging Findings with the Levels of Cardiac Enzymes in a 17-Year-Old

Abstract

Background: Diphtheria, caused by Corynebacterium diphtheriae, remains a life-threatening infectious disease in regions with low vaccination uptake. Myocarditis, a severe cardiac complication of diphtheria, is a leading cause of mortality. Despite the success of vaccines in reducing diphtheria cases, sporadic cases continue to occur, leading to significant health complications.

Objective: This case report aims to present the clinical course, electrocardiogram (ECG) and cardiac imaging findings, and serial levels of serum troponin in a 17-year-old patient with diphtheritic myocarditis, and to discuss the management and outcomes.

Methods: This study was conducted at Lady Reading Hospital, Peshawar, Pakistan. Ethical approval was obtained from the hospital's ethical review board, and informed consent was acquired from the patient and guardians. A comprehensive diagnostic workup was performed, including clinical examination, laboratory tests, ECG, transthoracic echocardiography (TTE), and cardiac magnetic resonance imaging (MRI). The patient’s vital signs, blood pressure, pulse rate, and jugular venous pressure were recorded. Laboratory tests included leukocyte count, erythrocyte sedimentation rate (ESR), and serial serum troponin measurements. ECG findings were documented, and TTE was used to assess left ventricular ejection fraction (LVEF). Cardiac MRI was performed to identify myocardial edema and delayed enhancement. Treatment included intravenous diuretics, ACE inhibitors, SGLT2 inhibitors, benzylpenicillin, and corticosteroids. Data were analyzed using SPSS version 25.0.

Results: The patient presented with a blood pressure of 110/70 mmHg and a pulse rate of 88 bpm. Initial laboratory tests showed a normal leukocyte count, ESR of 45 mm/hr, and troponin levels of 25 ng/ml, which decreased to 21.85 ng/ml and then to 8 ng/ml. ECG revealed ST segment depressions in the precordial leads. TTE showed an initial LVEF of 50%, declining to 35% and then to 28% within a week. Post-treatment, LVEF improved to 44% and subsequently to 55% at four weeks. Cardiac MRI indicated myocardial edema in the apical anterior and apical septal walls, with intramyocardial and subepicardial delayed enhancement.

Conclusion: Diphtheritic myocarditis can lead to rapid and severe deterioration of cardiac function. Early diagnosis and aggressive treatment, including the use of advanced imaging techniques and comprehensive medical therapy, can result in significant improvement in cardiac function and patient outcomes. Public health initiatives to improve vaccination coverage are essential to prevent such life-threatening complications.