A rare case of pulmonary valve infective endocarditis in a patient with ventricular septal defect

Abstract

Right-sided infective endocarditis (IE) is rare and often affects the tricuspid valve. We report a unique case of pulmonary valve IE in a patient with a predisposing congenital heart defect – a ventricular septal defect (VSD). A 23-year old man with a VSD was admitted following 3 months’ history of fever and malaise. An initial transthoracic echocardiogram (TTE) failed to reveal any visible vegetations or mass. However, blood cultures revealed persistent methicillin-sensitive S taphylococcus aureus (MSSA). A transoesophageal echocardiogram (TOE) showed multiple hyperechoic structures in the entirety of the anterior cusp of the pulmonary valve, suggestive of vegetations. In view of his young age and subacute presentation, a trial of prolonged antibiotics was opted for. The patient was commenced on intravenous cloxacillin for 6 weeks, which was successful. Common risk factors for right-sided IE include intravenous drug abuse, central venous catheterization and alcoholism. Less common risk factors include left-to-right shunts, including VSD. Proposed mechanisms include turbulent jet flow causing damage to the valve and vegetation formation. Although response to antibiotics and prognosis in right-sided IE tend to be better than in left-sided IE, surgical intervention may still be indicated, and unfortunately, evidence remains scarce on the appropriate patient selection for surgical intervention. Isolated pulmonary valve IE due to predisposing VSD remains a rare entity. It is important to consider this diagnosis in prolonged pyrexia of unknown origin in individuals with known congenital heart defects.