Acute Infective Endocarditis Involving Tricuspid Valve
  • "View is of the inflow tract of the right ventricle showing the tricuspid valve
    • Note the thin plaque-like vegetation outlined by two arrows, and that it has extended onto the underlying ventricular endocardium .  This is a fully developed bacterial endocarditis, which could be missed on echocardiogram.
  • "Etiology
    • Strep-, staph- and enterococci are most common organisms. Almost all bacteria, fungi, chlamydiae, and rickettsia occur.
    • Non-intravenous drug abuse (IVDA) cases mostly S. viridans of low virulence. B-hemolytic strep. sp. and Staph aureus highly virulent
    • IVDA cases:S. aureus common. Strep- enterococci, gram neg. bacilli and fungi (Candida, aspergillus) also seen.
  • Pathogenesis
    • Non-IVDA  cases. Transient bacteremia from obvious infections or from trivial injuries (teeth brushing) seed valves
    • IVDA cases. High doses of pathogens delivered with dirty needles affecting right side commonly.
    • Existing immunosuppression (HIV, organ transplants, alcoholism) increases risk.
  • Epidemiology
    • Non-IVDA cases.  Most have some existing abnormality: Congenital septal or valve defect;  healed rheumatic valvulitis; prolapse mitral valve; calcific aortic stenosis.  Some have apparently normal valves with minimal degenerative changes.
    • IVDA cases.  Most have normal valves.  Left sided lesions predominate of right-sided valves commonly affectedthan
  • General Gross Description
    • Vegetation are often bulky, with irregular friable surfaces, and may extend to adjoining endocardium and chordae tendinae.  Destructive, with defects in valve structure, and with invasion along annulus to form a 'ring' abscess. Size and destructiveness of vegetations directly proportional to virulence of organism.
    • Less virulent organisms may have flatter vegetations, invisible on echocardiography
  • References:
    • Cotran, R.S., Kumar, V., Robbins, S.L.: Robbins Pathologic Bases of Disease.  This addition, Philadelphia, WB Saunders, 1994, pp. 550-554."
  • Description/Synopsis by: J. Hasson, M.D.
  • Image Contribution by UCHC