A Case of Indolent Endocarditis

1Department of Medicine; 2Department of Pathology, McGill University, Montreal, Quebec Correspondence: Dr Hanane Benbarkat, 687 Pine Avenue, Room 10.02, Montreal, Quebec H3A 1A1. Telephone 514-843-1506, fax 514-843-1725, e-mail hanane.benbarkat@mail.mcgill.ca case presentation A 69-year-old man with aortic stenosis underwent coronary artery bypass grafting and bioprosthetic aortic valve replacement (AVR) in November 2007. His medical history was remarkable for a polypectomy in 2007, gout and chronic kidney disease (creatinine level at presentation 150 μmol/L). In September 2008, the patient presented to the hospital with fever and a right middle cerebral artery infarct. His neurological symptoms ultimately resolved. An echocardiogram demonstrated vegetation on the aortic valve bioprosthesis with a periaortic abscess. Blood cultures grew Staphylococcus epidermidis. An increase in the size of the periaortic abscess one month later, despite appropriate intravenous antibiotic therapy, required another AVR (Carpentier Edwards Magna 23 bioprosthesis, Edwards Lifesciences LLC, USA). He was then treated with antibiotics for an additional six weeks. The prosthesis culture grew Penicillium species 11 days after his surgery, and valve pathology showed fungal hyphae one month later (Figure 1). The patient was asymptomatic. He was offered amphotericin B treatment but refused. He remained asymptomatic until May 2010 when he presented with a two-week history of exertional dyspnea. He developed a cold right leg two days before this presentation. On examination, he was afebrile with normal blood pressure and heart rate. Chest examination was unremarkable. Cardiovascular examination revealed a 2/6 systolic ejection murmur at the left second intercostal space with radiation to the right supraclavicular space. There was no diastolic murmur. The jugular venous pressure was normal. The right leg was cold and peripheral pulses were nonpalpable. Laboratory investigations showed a normal white blood cell count, an erythrocyte sedimentation rate of 82 mm/h and his chest x-ray was normal. The PR interval on the electrocardiogram was 280 ms compared with 200 ms in October 2008. A repeat echocardiogram demonstrated a 27 mm × 15 mm vegetation on the aortic bioprosthesis with a periaortic mass highly suggestive of an aortic root abscess. The mean gradient across the aortic valve had increased to 43 mmHg from 14 mmHg in June 2009. The patient was empirically treated for prosthetic valve endocarditis with vancomycin, gentamycin and rifampin.