P1266 Infectious endocarditis- still a diagnostic dilemma

INTRODUCTION Infectious endocarditis is still a challenge with a high mortality and complication rate despite the progress made in its management. DESCRIPTION OF CLINICAL CASE A 58 years old female, with a history of mitral and aortic mechanical prosthesis for rheumatic valvular disease and mitral infectious endocarditis with Aggregatibacter Actinomycetemcomita due to an apical abscess was referred to our service for persistent fever. The clinical examination revealed irregular mechanical prosthesis beats, with no heart murmurs and no signs of heart failure, but with a tender splenomegaly. The laboratory tests showed an inflammatory syndrome, but no positive blood cultures. An extensive panel for endocarditis was negative for Coxiella burnetii, Brucella Spp, Legionella Spp, Mycoplasma Spp and for the immunology markers (rheumatoid factor, antinuclear antibodies and anti-cardiolipin antibodies) ECG AF, 88 bpm, PVC bigeminy, LBBB. Infectious endocarditis was the most likely diagnosis considering the fever, the inflammatory syndrome, the presence of the mechanical valves and the history of endocarditis. An echocardiography was performed that showed a non-dilated left ventricle with a preserved EF, no aortic prosthesis dysfunction, nor mitral; a dilated RV with normal function, moderate tricuspid regurgitation, no intracardiac masses and no pericardial effusion. The TEE revealed no vegetation, no abscess or pseudoaneurysms and no dehiscence of the prosthetic valves. The Endocarditis Team was reunited and empirical antimicrobial therapies with Amoxiciline, Gentamicine and Cloxaciline for 6 weeks, as well as a PET scan were recommended. The PET-CT revealed abnormal fixation in the posterior-inferior part of the aortic valve. As we had only one major criterion and two minor criteria for the diagnosis of endocarditis a radiolabeled leukocytes SPECT CT that showed no pathological fixation was realised. The result was inconclusive as it was performed at the end of the antimicrobial treatment. A computed tomography of the brain, thorax, abdomen and pelvis didn’t reveal any vascular phenomena. The tender splenomegaly was secondary to two hemangiomas. Also a dental computed tomography revealed an apical abscess of 1.2 that was treated after discharge with antibiotic prophylaxis. DISCUSSION This clinical case confirms that the diagnosis on infectious endocarditis can be challenging in patients with prosthetic valves. The multimodality imaging is of major importance for the diagnosis of these patients. Additionally the microbiological criteria was not met in this case as it was a blood culture-negative endocarditis with a history of previous antibiotic therapy. CONCLUSION Our knowledge of infectious endocarditis is constantly evolving. Blood culture negative endocarditis accounts for one third of cases and is still a challenge. The Endocarditis Team and multimodality imaging play a central role in the diagnosis and treatment of these patients. Abstract P1266 Figure. PET-CT showing AV abnormal fixation