A myocardial abscess is a rare and potentially fatal condition. Various case reports have revealed the presence of myocardial abscess at different anatomic locations of the myocardium, including the atria auricles [1], ventricular free wall [2], interventricular septum [3], and perivalvular region [4]. Myocardial abscess has been reported in about 20% of patients with infective endocarditis, which is the most common predisposing factor [5]. The occurrence of myocardial abscess without any evidence of infective endocarditis is a rare finding and is infrequently reported in medical literature. We report a case of myocardial abscess within the inferior wall of the LV that was incidentally detected during autopsy in a patient brought after sudden death to a casualty.

A 65-year-old lady was brought dead as a casualty. She was on prolonged use of antidepressants and had no significant cardiac history. On dissection of the heart during the autopsy, there was more than 70 percent stenosis of the anterior coronary, circumflex coronary, and right coronary arteries. The wall of the left ventricle showed hypertrophy of the cardiac musculature, and the inferior wall showed two small cavities filled with pus, which were drained away on washing. A complete autopsy did not reveal any non-cardiac cause of death.

The abscess cavity showed clear margins and the pus inside was completely washed away. Cause of death was reported as due to complications of coronary artery disease and myocardial abscess.

Myocardial abscess is a suppurative infection of the heart, and it is usually associated with infective endocarditis. The predilection sites of myocardial abscess are heart valve ring areas, especially the AV region (native or prosthetic valve); probably because these areas are fibrous and relatively avascular [6]. Nonvalvular isolated mural abscess is a rare condition and can be found in the setting of septicemia without infective endocarditis. Following detailed literature research, it has been found in relation to septic foci such as decubitus ulcer, infected burns, bronchiectasis, and thrombophlebitis in patients with immunodeficiency [7]. Moreover, one case report demonstrated myocardial abscess at the site of infarcted myocardium [8]. None of the aforementioned conditions existed in our patient.

The pathophysiology of an isolated myocardial abscess without infective endocarditis is quite different. Unlike the routine course of endocarditis, an isolated myocardial abscess is anatomically not associated with the valvular annulus and occurs when bloodstream infection causes focal bacterial myocarditis that progresses to liquefactive necrosis [9]. There are two principle ways of myocardial abscess formation:

(1) By dissemination from a distant infectious focus via coronary embolization of septic material; and

(2) By contiguity from a process located in the heart itself.

The rarity of an isolated myocardial abscess without any association with endocarditis suggests that myocardium is relatively impervious to bloodstream inoculation. This is supported by the fact that myocardial abscess is usually associated with impaired local immunity, involving either a fresh infarct, the scar from an old infarct, or a coronary stent [10].

In the past, most cases of myocardial abscess were detected during autopsy. But nowadays, prior detection of a myocardial abscess can be carried out by noninvasive diagnostic modalities, including echocardiography, computed tomography scans, and cardiac magnetic resonance imaging. Despite advances in diagnostics, the identification of myocardial abscesses still remains a challenge. This could be ascribed to a low index of disease suspicion as well as the low sensitivity of the available diagnostic measures. Echocardiography is accepted as a non-invasive gold standard technique to detect infective endocarditis and myocardial abscess. TEE has an improved sensitivity (90%), in comparison to TTE (50%). In addition, the transesophageal approach provides better detection of perivalvular abscesses, associated vegetation, valvular perforations, fistulae, and rupture of chordae tendineae, especially in mitral prosthetic valves. Although specificity higher than 90% has been reported for both approaches, TEE always needs to be performed whenever an abscess is suspected on TTE. However, small anterior abscesses, sometimes difficult to diagnose by a transesophageal approach, may be better evaluated only by TTE. Consequently, both approaches are complimentary to each other and mandatory for suspected patients. On echocardiography, myocardial abscess appears either as a thickened and non-homogenous echo-dense area due to suppuration in the early stage or as an echo-lucent and clear free-space in the old healed stage. In the healed stage, echocardiography typically shows a zone of reduced echo density without any color flow, making the diagnosis easy [11]. An exact morphologic evaluation, including the volume and extent of the abscess and its relation to the coronary arteries, is mandatory to plan the management of the disease. The complications of myocardial abscess, like pseudoaneurysm and fistulization, may also be diagnosed by TEE. The typical echocardiographic appearance of a pseudoaneurysm is a pulsatile echo-free space with color Doppler flow inside. The formation of a fistula may be a complication of both abscesses and pseudoaneurysms.

The clinical picture of a patient with a myocardial abscess may vary from an asymptomatic state to myocardial wall rupture. On investigation, the ECG usually does not show any specific changes. However, according to the literature, few cases have presented with fatal arrhythmia (ventricular tachycardia or fibrillation), PR prolongation, or a complete heart block [12]. The management of patients with myocardial abscesses depends on clinical and imaging features, along with complications. Management varies from intensive medical treatment with antibiotics to surgical abscess drainage and repair of the defect. Many patients present with smaller abscesses without any complications. Therefore, it has been suggested that such patients must be monitored closely, with serial TEE at intervals of 2, 4, and 8 weeks after completion of antimicrobial therapy [13]. According to a literature review, about 40% of cases involve more than one microbial etiology in myocardial abscess, and gram-negative infections are often related to debilitating conditions [14]. Bacterial agents usually implicated are Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella, Streptococcus viridans, and Salmonella species [15]. Accordingly, we used third-generation cephalosporin with β-lactamase inhibitor along with aminoglycoside as an empirical antibiotic.

This was a rare case of an isolated myocardial abscess in the free wall of the left ventricle without any other evidence of infective endocarditis, an incidental finding during an autopsy. Hence, it demonstrates that myocardial abscess can be a cause of sudden death in patients with no previous cardiac history.

Declaration of Patient Consent

The authors certify that they have obtained all appropriate patient consent forms. In this form, the patients’ relatives have given their consent for her images and other clinical information to be reported in the journal. The patients’ relatives understand that their names and initials will not be published and that due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial Support and Sponsorship

Nil.

Conflicts of Interest

There are no conflicts of interest.

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