Bacteremia with gram positive bacteria - when and how do I need to look for endocarditis?

BACKGROUND: Patients with bacteremia caused by gram positive bacteria are at risk for infective endocarditis (IE). Since IE needs long antibiotic treatment and sometimes heart valve surgery, it is very important to identify patients with IE.

OBJECTIVES: In this narrative review we present and discuss how to determine which investigations to detect IE that are needed in individual patients with gram positive bacteremia.

SOURCES: Published original studies and previous reviews in English, within the relevant field are used.

CONTENT: First, the different qualities of the bacteremia in relation to IE-risk are discussed. The risk for IE in bacteremia is related to the species of the bacterium but also to monomicrobial bacteremia and the number of positive cultures. Secondly, patient-related factors for IE risk in bacteremia are presented. Next, the risk stratification systems to determine the risk for IE in gram positive bacteremia caused by Staphylococcus aureus, viridans streptococci and Enterococcus faecalis are presented and their use is discussed. In the last part of the review, an account for the different modalities of IE-investigations is given. The main focus is on echocardiography which is the cornerstone of IE-investigations. Furthermore, 18 F-FDG PET/CT and cardiac CT are presented and their use is also discussed. A brief account for investigations used to identify embolic phenomena in IE is also given. Finally, we present a flow-chart suggesting which investigations to perform in relation to IE in patients with gram positive bacteremia.

IMPLICATIONS: For the individual patient as well as the healthcare system, it is important both to diagnose IE and to decide when to stop looking for IE. This review might be helpful in finding that balance.