Infective endocarditis

Diagnosis: The infective endocarditis of the right side — the intravenous-drug use, the fever and the night sweats, the tricuspid regurgitation murmur (the lower-left-sternal-edge pansystolic), and the septic pulmonary emboli (the bilateral infiltrates), with the Staphylococcus aureus bacteraemia. This meets the definite Duke criteria — the two major (the typical organism in the blood culture, the endocardial involvement to be confirmed on the echo) and the minors (the predisposition of the intravenous-drug use, the fever, the vascular phenomena of the septic pulmonary emboli).

Investigations: The blood cultures already taken (the three sets, the Staphylococcus aureus — a Duke major criterion regardless of nosocomial acquisition). The echocardiography — harmonic TTE first (61% sensitive, 94% specific vs TEE), with TEE almost always required after, since modern TTE still misses many TEE-detected vegetations.^[2] The bloods — the full blood count, the inflammatory markers, the renal function and the urinalysis, the liver function. The ECG (the new conduction defect = the abscess). The HIV and the hepatitis testing (the intravenous-drug use).^[1]

Management:

• The admission, the intravenous access, the monitoring.
• The organism-directed intravenous antibiotics for the Staphylococcus aureus — penicillinase-resistant penicillin, vancomycin, or daptomycin per local MRSA prevalence, plus gentamicin — per local microbiology and sensitivities. Native-valve treatment spans 2–6 weeks from first effective therapy; outpatient treatment suits stabilised uncomplicated cases.
• The search for and the removal of the source — the peripheral access, the indwelling lines, the harm-reduction counselling.
• The surgery — early intervention without delay for complicated cases; an isolated vegetation is not an indication. Consider large vegetations, severe regurgitation with right-heart failure, or persistent bacteraemia; repair is preferred over replacement in the drug-user where feasible.
• The complications — the monitoring for the embolisation, the heart failure, the metastatic infection.