Cardiology for MRCP Part 2

A 38-year-old man with a history of intravenous drug use presents with three weeks of fever and malaise. Blood cultures grow Staphylococcus aureus in three sets. Echocardiography shows a 14 mm mobile vegetation on the tricuspid valve. He develops new pleuritic chest pain and CT shows multiple peripheral cavitating lung lesions. He remains haemodynamically stable on flucloxacillin. What is the most appropriate next step?

1. Add rifampicin and gentamicin routinely Wrong as a reflex. Rifampicin has a role in prosthetic valve infection, and routine aminoglycoside addition in native valve staphylococcal endocarditis increases nephrotoxicity without improving outcome.
2. Continue targeted intravenous antibiotics and discuss with the endocarditis multidisciplinary team correct Correct. Right-sided staphylococcal endocarditis with septic pulmonary emboli in a haemodynamically stable patient is usually managed medically with a prolonged targeted antibiotic course. The formal endocarditis team discussion is itself the standard of care and is what decides whether surgery is needed.
3. Switch to oral flucloxacillin and arrange outpatient follow-up Wrong at this point. Early oral switch strategies exist but apply to selected, stabilised, left-sided disease after an initial intravenous phase and within a structured programme, not to an actively embolising patient in the first weeks.
4. Immediate tricuspid valve replacement Wrong at this stage. Surgery in right-sided disease is reserved for persistent bacteraemia despite adequate therapy, right heart failure, or very large vegetations that continue to embolise. He is stable and has had a short course.
5. Anticoagulate with a therapeutic heparin infusion to prevent further emboli Wrong and harmful. Anticoagulation does not prevent septic embolisation and increases the risk of haemorrhagic transformation of embolic lesions.

The point: Right-sided endocarditis in people who inject drugs is usually staphylococcal, embolises to the lungs rather than the brain, and is usually treated medically. Surgical indications across endocarditis: heart failure, uncontrolled infection, and prevention of embolism.

Source: ESC guidelines for the management of endocarditis European Society of Cardiology · tier 2, specialty society or college