Paradoxical systemic manifestations from right-sided infective endocarditis via a transient intrapulmonary shunt: a case report

Right-sided infective endocarditis (RSIE) commonly causes septic pulmonary embolism, whereas systemic manifestations typically suggest concomitant left-sided infective endocarditis or an intracardiac right-to-left shunt such as patent foramen ovale (PFO).

A 24-year-old man with atopic dermatitis presented with fever and painful distal extremity skin lesions. Three sets of blood cultures grew Staphylococcus aureus. Transthoracic echocardiography (TTE) revealed a highly mobile, club-shaped vegetation (18.6 × 10 mm) adjacent to the tricuspid valve with severe tricuspid regurgitation due to leaflet perforation. Agitated-saline contrast TTE demonstrated right-to-left shunting with Grade III microbubble appearance in the left heart after five cardiac cycles following release of Valsalva manoeuvre, whereas no microbubbles were detected in the left heart at rest. Transoesophageal echocardiography confirmed no PFO and no left-sided vegetation. Chest computed tomography (CT) demonstrated multiple pneumonia and lung abscesses with cavities, consistent with septic pulmonary embolic disease, and discitis was confirmed on magnetic resonance imaging. Skin biopsy of the distal extremity lesions was consistent with septic micro-embolization. Empirical intravenous antibiotics were initiated and then tailored to susceptibility results. Antibiotic therapy continued for 6 weeks from the first documented negative blood culture. The vegetation regressed without surgery and pulmonary lesions improved. At 12-month follow-up, chest CT showed improvement of lung complications, and repeat agitated-saline contrast TTE suggested disappearance of right-to-left shunting.

This case represents a plausible mechanism of paradoxical systemic manifestations in RSIE via a transient intrapulmonary shunt during severe septic pulmonary embolic disease.