A 28-year-old intravenous drug user develops fever, new-onset right-sided heart failure, and multiple pulmonary septic emboli. Blood cultures grow Staphylococcus aureus. The valve MOST commonly affected in IV drug user–associated infective endocarditis is the:
- A Mitral valve
- B Aortic valve
- C Tricuspid valve ✓
- D Pulmonary valve
Correct answer: C. Tricuspid valve
Explanation
Right-sided infective endocarditis predominates in intravenous drug users due to direct venous inoculation; the tricuspid valve is affected in ~50–60% of cases, causing septic pulmonary emboli rather than peripheral emboli. S. aureus is the predominant pathogen. In contrast, non-drug-user endocarditis usually affects the aortic or mitral valves.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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