Endocarditis (IE)

Question 1

What is Endocarditis?

Answer 1

Inflammation of the endocardium that lines the surface of cardiac valves
-Usually due to bacterial infection

Question 2

What is the overall most common cause of endocarditis?

Answer 2

Streptococcus viridans

Question 3

What is the significance of streptococcus viridans causing endocarditis?

Answer 3

• 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)

Question 4

What is the pathogenesis of IE caused by streptococcus viridans?

Answer 4

1. Damaged endocardial surface develops thrombotic vegetations (platelets and fibrin)
2. Transient bacteremia leads to trapping of bacteria in the vegetations

Question 5

What decreases the risk of endocarditis?

Answer 5

Prophylactic antibiotics

Question 6

What is the most common cause of IE in infectious drug users?

Answer 6

Staphylococcus aureus

Question 7

What is the pathogenesis of IE caused by Staphylococcus aureus?

Answer 7

• 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)

Question 8

What is staphylococus epidermis associated with?

Answer 8

Endocarditis of prosthetic valves

Question 9

What is streptococcus bovis associated with?

Answer 9

Endocarditis in patients with underlying colorectal carcinoma

Question 10

What organisms are associated with endocarditis with negative blood cultures?

Answer 10

HACEK organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella)
-These are very difficult to grow!

Question 11

What are the four clinical features of bacterial endocarditis? What causes them?

Answer 11

1. Fever - due to bacteremia
2. Murmur - due to vegetations on the heart valve
3. 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
4. Anemia of chronic disease - due to chronic inflammation

Question 12

What is a useful tool for detecting lesions on valve in IE?

Answer 12

Transesophageal echocardiogram

Question 13

What is NONbacterial endocarditis?

Answer 13

Due to sterile vegetations

Question 14

What causes the sterile vegetations of NONbacterial endocarditis?

Answer 14

They are associated with:

• Hypercoagulable state
• Underlying adenocarcinoma

Question 15

What do vegetations from NONbacterial endocarditis cause?

Answer 15

Vegetations on the mitral valve along lines of closure result in mitral regurgitation!

Question 16

What are two laboratory findings in IE?

Answer 16

1. Positive blood cultures
2. Anemia of chronic disease (Low Hg, Low MCV (microcytic), High fourteen, Low TIBC, Low serum iron and Low percent saturation)

Question 17

What is Libman-Sacks endocarditis?

Answer 17

Due to sterile vegetations that arise in association with SLE!

Question 18

Where are vegetations present in Libman-Sacks endocarditis?

Answer 18

Vegetations are present on the surface and undersurface of the mitral valve and result in mitral regurgitation.