Thrombus or vegetation? The importance of following the duke criteria for infective endocarditis before proceeding with advanced cardiac imaging

ABSTRACT

Case Report We present a case of a middle-age male who based on the Duke criteria (DC), we were able to rule out infective endocarditis (IE) before proceeding with advanced imaging. Case We present a case of a 51-year-old man with past medical history of heroin and cocaine use disorder, that was admitted to the intensive care unit (ICU) becouse COVID-19 pneumonia. On day 1 of admission, transthoracic echocardiogram (TTE) showed moderate tricuspid regurgitation. In the ICU, blood cultures (BC) were positive for Staphylococcus coagulase-negative species, patient received a course of vancomycin for 7 days. On day 17, the patient had repeat TTE, which showed new nodular thickening of the tricuspid valve associated with tricuspid regurgitation. BC were sent that same day, and they grew out Staphylococcus coagulase-negative species. At that time, it was not clear if new tricuspid valve findings were secondary to vegetation or a thrombus. The DC for infective endocarditis was applied to determine whether the findings on the TTE were due to IE. Major criteria include positive blood cultures and findings of vascular vegetation on echocardiography. After analyzing the BC and meeting with the microbiology personnel, it was found that the Staphylococcus coagulase-negative species found were different from each other. However, there was a possible vegetation present, shown on echocardiography. The patient had predisposing heart condition of tricuspid regurgitation and a history of IV drug abuse. Fever was absent. As for vascular phenomena, the patient did not have skin changes and no pulmonary embolism was found following chest CT protocol. As for immunologic phenomena, the patient did not have Roth spots or glomerulonephritis. Lastly, for microbiological evidence, the patient's blood cultures were possibly positive due to contamination. Based on the DC the patient had a possible diagnosis of IC but it was rejected because a patient had a firm alternative diagnosis, mainly a ventricular thrombus. The patient received anticoagulation treatment for thrombus, and he was discharged on his 24th day of hospitalization without complications. Discussion The diagnosis of IE remains difficult due to low specificity of the laboratory and imaging tests. Our patient had all the risk factors to believe it was endocarditis instead of a thrombus. Based on the DC, endocarditis was ruled out and the patient responded well to anticoagulation. More studies are needed to clarify the utility of the DC as a method to differentiate IE from thrombus before proceeding with advanced imaging.