Recurrent infective endocarditis as a manifestation of Loeffler's endocarditis: The diagnostic importance of cardiac magnetic resonance imaging

Hypereosinophilic syndrome (HES) affects many organ systems. Cardiac involvement is common and a major cause of morbidity and mortality in patients with HES.We present a 60-year-old patient with a history of recurrent infective endocarditis due to different Streptococcus species. Transthoracic echocardiography (TTE) revealed a circumscript echodense structure near the apex of the left ventricle, suggestive of a vegetation. Positron emission tomography revealed increased activity at the same site of the left ventricle and showed no other abnormalities. The patient was treated with intravenous antimicrobial therapy for each episode of infective endocarditis (3x). The vegetation near the apex remained visible on follow-up TTE. Diagnostic cardiac magnetic resonance imaging (CMR) was performed and showed left ventricular wall thickness, and diffuse subendocardial delayed enhancement in a patchy pattern. These findings are strongly suggestive of Loeffler's endocarditis. Bone marrow biopsy showed increased percentage of eosinophilic granulocytes, confirming the diagnosis of hypereosinophilic syndrome (HES).The presence of infective endocarditis and simultaneous Loeffler's endocarditis has been reported once before by Menz et al. in 1994 published in Hertz. This case emphasizes the role of CMR as a diagnostic modality for Loeffler's endocarditis. Our patient had no peripheral hypereosinophilia. Myocardial biopsy conveys an increased risk for thromboembolic events and the possibility of a false negative result. CMR however, raised the suspicion of Loeffler's endocarditis, a diagnosis that was subsequently confirmed by bone marrow biopsy. The patient was treated with acenocoumarol and oral prednisone, which was gradually tapered after addition of mycophenolate mofetil.