Fulminant Influenza A myocarditis in a patient presenting with cardiogenic shock and biventricular thrombi: a case report

Abstract

Background: Acute myocarditis is a common condition, with viral infections being the most common aetiology in North America and Europe. Influenza A myocarditis is however rare. As clinical manifestation may be fulminant, early recognition and management are paramount and may impact overall prognosis by hindering complications such as thromboembolism. A brief review of the literature, diagnostic modalities, work-up and treatment are discussed.

Case summary: We present the case of a 42-year-old, previously healthy woman with recent flu-like symptoms, developing decompensated heart failure (HF) and cardiogenic shock within a week, due to Influenza A myocarditis. Biventricular thrombi were identified. Pharmacological haemodynamic support, followed by HF therapy, allowed full recuperation of heart function. Intracavitary thrombi disappeared under unfractionated heparin with bridging to rivaroxaban.

Discussion: Fulminant myocarditis due to Influenza A is rare and, to the best of our knowledge, has not been associated with intracardiac thrombi formation. Echocardiography is the essential first-line imaging modality. Cardiac magnetic resonance plays a major role in the diagnosis of myocarditis and may preclude the need for an endomyocardial biopsy in selected cases. Coronary angiography may be required to rule out ischaemic aetiology. First-line therapy in fulminant disease is pharmacological and, if required, mechanical haemodynamic support. Standard HF therapy complete the therapeutic options and should be introduced as soon as possible. Complications such as intracardiac thrombi formation, require targeted treatment. Specific drug therapies targeting Influenza A have no proven benefit in myocarditis.

Keywords: Acute myocarditis; Cardiogenic shock; Case report; Influenza A; Intracardiac thrombus.

Figure 1

Sagittal view of the contrast chest computed tomography revealing bilateral pleural effusion (white stars) and the presence of a left ventricular thrombus (horizontal white arrow), as well as a right ventricular one (vertical white arrow).

Figure 2

Modified two-chamber view showing a 22 × 15 mm pedunculated thrombus in the inferior apical segment of the left ventricle.

Figure 3

Cardiac magnetic resonance images. (A) Three-chamber late gadolinium enhancement view showing infero-lateral subepicardial enhancement (white arrow); (B) short-axis late gadolinium enhancement mid-cavity view showing the same area of infero-lateral subepicardial enhancement (white arrow); (C) T2-weighted short-tau inversion recovery sequence showing a short-axis mid-cavity view with enhanced signal (oedema) of the subepicardial infero-lateral wall (white arrow).