Clinical meaning
Infective endocarditis vegetations consist of fibrin, platelets, and trapped bacteria forming on valve endothelium. Vegetation size >10mm, mobility, and mitral valve location increase embolic risk. S. aureus produces biofilm and tissue-destructive enzymes, causing rapid valve destruction, abscess formation, and high embolic rates.
Diagnosis & workup
Diagnostics & workup: - Order 3 sets of blood cultures from separate sites before antibiotics - Order TEE (superior sensitivity for vegetations, abscess, perforation) - Order Modified Duke Criteria assessment - Order CT head if neurological symptoms (embolic stroke) - Order splenic imaging if left upper quadrant pain - Order ECG serially (new AV block suggests perivalvular abscess)
Risk factors: - Prosthetic heart valves - IV drug use (right-sided IE) - Structural heart disease - Implantable cardiac devices - Poor dentition - Healthcare-associated bacteremia - Immunosuppression