Pathology of Endocarditis Flashcards
What is endocarditis?
inflammation of endocardium that lines the surface of cardiac valves; usually due to bacterial infection.
Can lead to death in days to weeks.
What is the most common cause of endocarditis?
Strep viridans, but this is a low-virulence organism that can only infect PREVIOUSLY DAMAGED valves (ex. by chronic rheumatic heart disease or MVP). Thus, because it is low virulence, it will result in small vegetations that do not destroy the valve (SUBACUTE endocarditis).
*Most patients recover with antibiotic therapy.
What happens during the pathogenesis of endocarditis?
the damaged endocardial surface develops thrombotic vegetations (platelets and fibrin). These act as a trap now for any transient bacteremia (ex. bacteria from a dental procedure), that will now lead to infectious endocarditis.
What bacteria is the most common cause of endocarditis in IV drug users?
Staph aureus. This is a HIGH-virulence organism that will infect normal valves, most commonly the TRICUSPID valve (bc they are injecting into the veins), and result in large vegetations that destroy it. This causes acute endocarditis.
What bacteria most commonly infects prosthetic valves?
Staph epidermidis. Thromboembolic complications are seen mostly with mechanical valves and requires anticoagulant therapy.
What bacteria is associated with endocarditis in patients with underlying colerectal carcinoma?
Strep bovis
What are the HACEK organisms that are associated with endocarditis with negative blood cultures (bc they are difficult to grow)?
Haemophilus Actinobacillus Cardiobacterium Eikenella Kingella
**What are the clinical features of endocarditis?
- Fever due to bacteremia.
- Murmur due to vegetations on heart valve.
- Janeway lesions= erythematous NONtender lesions on palms and soles.
- Osler nodes= TENDER lesions on fingers or toes. Remember “ouch, ouch, osler.”
- splinter hemorrhages in nail bed.
- Roth spots= retinal hemorrhages due to embolization of septic vegetations.
- anemia of chronic disease= due to chronic inflammation.
What are the laboratory findings of endocarditis?
- positive blood cultures
- anemia of chronic disease= low Hb, low MC, high ferritin, low TIBC (total iron binding capacity), low serum iron, and low % saturation.
What is a good way to detect lesions on the valves in endocarditis?
Transesophageal echocardiogram
What causes nonbacterial thrombotic endocarditis (Marantic endocarditis)?
due to SMALL sterile vegetations that arise in association with a HYPERCOAGULABLE state or underlying adenocarcinoma. These do NOT cause inflammation.
What does nonbacterial thrombotic endocarditis cause?
small vegetations on the AORTIC or mitral valve along LINES of CLOSURE and results in mitral regurgitation.
Often seen in debilitated pts with sepsis or cancer.
What is Libman-Sacks endocarditis?
due to sterile vegetations that arise in association with SLE.
What does Libman-Sack endocarditis cause?
vegetations on the surface and undersurface (aka both sides) of the mitral valve (or tricuspid) and result in mitral (or tricuspid) regurgitation.
*usually not of clinical significance :)
**What is carcinoid heart disease?
manifestation of carcinoid syndrome= bioactive products produced from carcinoid tumors that lead to flushing, cramps, nausea, and diarrhea. The effects on the heart involve the endocardium of the RIGHT side (TRICUSPID and PULMONIC valves; usually INSUFFICIENCY) causing plaque-like thickenings= smooth muscle cells and collagen in an ACID MUCOPOLYSACCHARIDE-RICH MATRIX.
