What is Endocarditis?
Inflammation of the endocardium that lines the surface of cardiac valves
-Usually due to bacterial infection
What is the overall most common cause of endocarditis?
Streptococcus viridans
What is the significance of streptococcus viridans causing endocarditis?
- Low virulence organism (small vegetations)
- Infects perviously damaged valves (Chronic Rheumatic Heart Disease & MVP)
- Results in small vegetations that do not destroy the valve (subacute endocarditis)
What is the pathogenesis of IE caused by streptococcus viridans?
- Damaged endocardial surface develops thrombotic vegetations (platelets and fibrin)
- Transient bacteremia leads to trapping of bacteria in the vegetations
What decreases the risk of endocarditis?
Prophylactic antibiotics
What is the most common cause of IE in infectious drug users?
Staphylococcus aureus
What is the pathogenesis of IE caused by Staphylococcus aureus?
- It’s a high virulence organism that infects normal valves, most commonly the tricuspid (right heart)
- Results in LARGE vegetations that destroy the valve (acute endocarditis)
What is staphylococus epidermis associated with?
Endocarditis of prosthetic valves
What is streptococcus bovis associated with?
Endocarditis in patients with underlying colorectal carcinoma
What organisms are associated with endocarditis with negative blood cultures?
HACEK organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella) -These are very difficult to grow!
What are the four clinical features of bacterial endocarditis? What causes them?
- Fever - due to bacteremia
- Murmur - due to vegetations on the heart valve
- Janeway lesions (erythematous contender lesions on palms and soles), Osler nodes (tender lesions on fingers and toes), splinter hemorrhages in nail bed and Roth spots - due to embolization of septic vegetations
- Anemia of chronic disease - due to chronic inflammation
What is a useful tool for detecting lesions on valve in IE?
Transesophageal echocardiogram
What is NONbacterial endocarditis?
Due to sterile vegetations
What causes the sterile vegetations of NONbacterial endocarditis?
They are associated with:
- Hypercoagulable state
- Underlying adenocarcinoma
What do vegetations from NONbacterial endocarditis cause?
Vegetations on the mitral valve along lines of closure result in mitral regurgitation!
What are two laboratory findings in IE?
- Positive blood cultures
- Anemia of chronic disease (Low Hg, Low MCV (microcytic), High fourteen, Low TIBC, Low serum iron and Low percent saturation)
What is Libman-Sacks endocarditis?
Due to sterile vegetations that arise in association with SLE!
Where are vegetations present in Libman-Sacks endocarditis?
Vegetations are present on the surface and undersurface of the mitral valve and result in mitral regurgitation.
