1
Q
Causes of infective endocarditis (3)
A
- Subacute infective endocarditis - underlying abnormalities - Strep viridans, Strep faecalis & other gram negs
- Acute infective endocarditis - normal valves, more virulent pathogens - Staph aureus - esp in IVDA
- Prosthetic valve endocarditis - Staph epidermidis
2
Q
Pathogenesis of infective endocarditis
A
Subacute
- Derangement of blood flow - jet streams, low pressure areas, turbulence
- Formation of sterile platelet-fibrin deposits on endocardium & valves (vegetations)
- Seeding by blood-borne organisms
- Clumping of bacteria due to agglutinating antibodies
Acute
1. High virulence pathogens - directly invade the endocardium & heart valves - rapidly destructive lesions
3
Q
Morphology of infective endocarditis
A
G:
- friable, bulky bacteria laden vegetation on heart valves
M:
- tangled mass of fibrin & masses of organisms
4
Q
Effects of infective endocarditis (2)
A
- Local
- valve rupture, scarring
- myocardial ring abscess
- suppurative pericarditis - Distant
- emboli - organ infarction, abscess formation
- immune complex mediated disorders - vasculitis, GN
- others - anemia of chronic disease, splenomegaly
5
Q
Clinical presentations of infective endocarditis
A
- splinter hemorrhages in nails - microthromboemboli
- Janeway lesions - erythematous/hemorrhagic non-tender lesions on palms/soles
- Osler nodes - subcutaneous nodules in the pulp of digits
- Roth spots - retinal hemorrhages
