Subvalvular Aortic Valve Abscess Causing Atrioventricular Abnormalities, Fever of Unknown Origin and Deteriorating Dyspnea: A Case Report

Background: We report the case of an infective endocarditis of a native aortic valve that, along with the vegetations of the aortic cusps, caused a massive subvalvular abscess. Clinically was manifested by dyspnea, persisting fever, symptoms of heart failure and atrioventricular conduction abnormalities, which in the acute setting led to the implantation of a dual chamber permanent pacemaker. Case summary: The patient was a 77-year old male, who had undergone routine dental procedures during the summer and was ultimately referred to our emergency department due to recurrent febrile episodes and progressively worsening exertional dyspnea. After a number of medical consultations, he was administered many different empirical antibiotic combinations, mainly targeting a possible lower respiratory infection, based on the patient's known smoking-induced COPD. Both the initial transthoracic and the subsequent transoesophageal echocardiographic reports in our establishment, revealed vegetations on the calcified cusps of a stenosed aortic valve, along with a large, drained cavity at the level of the sinuses of Valsalva. The most probable diagnosis was that of an endocarditis-induced subvalvular aortic root abscess. Discussion: Persistent fever, fulfilling the criteria of the notorious fever of unknown origin, should always raise the alarm about the need of a cautious approach and in-depth evaluation of the patient's history, clinical presentation, laboratory abnormalities, and imaging results. Empirical antibiotic combinations should not be the go-to solution, especially when dealing with a known valvulopathy and newly appearing electrocardiographic abnormalities. In such cases, clinical suspicion of infective endocarditis should be high. Most importantly, when permanent intracardiac devices are planned to be implanted, special attention to excluding sources of bacteraemia must be given. Imaging plays an irreplaceable role, with TOE generally setting the diagnosis while modern imaging techinques such as Cardiac 64-slice CT and 18F-FDG PET/CT-scan can be of great assistance in future.