Infective Endocarditis

Question 1

Infective endocarditis

Answer 1

Microbial infection of mural endocardium and heart valves

Question 2

Where does IE occur?

Answer 2

Close to congenital or acquired heart defects
Natural valves- affected by congenital heart defects/RHD
Prosthetic valves - early (staph epidermis) within 60 days of surgery HAI
Prosthetic valves- late (staph aureus/strep viridans/actinobaccilus) within 2-6 months of surgery CAI

Question 3

Heart valves

Answer 3

LHS- mitral (bicuspid) aortic (tricuspid)

RHS- tricuspid and pulmonary (tricuspid)

Question 4

Etiology

Answer 4

B/V/P/fungi (candida)
IVDU (staph aureus/tricuspid valve/affects young people)
Hemodialysis P (staph aureus)

Question 5

Epidemiology

Answer 5

<1% of general population affected
Increases with increasing age (less immunity more heart defects)
Young females (20% incidence)

Question 6

Risk factors

Answer 6

ARF males (aortic valve) females (mitral valve) 
Prosthetic valves 
IVDU
hemodialysis
history of IE

Question 7

Predisposing conditions

Answer 7

Mitral valve prolapse (in males over 45 years) 
Degenerative calcific valvular stenosis 
Aortic valve disease
IVDU prosthetic valves 
Congenital heart defect 
Idiopathic 25%

Question 8

Clinical course

Answer 8

Acute- highly virulent organism (staph aureus) infect normal HV and lots of necrotising destruction
Subacute- less virulent organism (strep viridans) infect abnormal HV and less necrotising destruction

Question 9

Paediatric IE

Answer 9

Usually due to underlying heart defect
Ventricular septal defect
Alteration in patency of ductus arteriosus
Tetralogy of fallout - overriding aorta/RV hypertrophy/changes in aortic valve/pulmonary valve stenosis

Question 10

Pediatric IE Etiology

Answer 10

Neonates- staph aureus/coagulase negative staph/group B strep
Children- staph aureus/strep viridans

Question 11

Adults IE

Answer 11

1st predisposing factor is MVP
P w/ murmurs at risk
Biscuspid aortic valve defect (M. >60 years) at risk
Congenital heart disease increases risk

Question 12

Pathophysiology

Answer 12

Injury to Ep barrier at gut/skin/oral cavity leading to bacteremia
Affects Natural valve- confined to valve leaflets
Affects prosthetic valve- extend beyond valve ring to annular and peri annular tissue (septal and ring abscess/PV splitting/fistula)
Early invasive infections can affect aortic valve

Question 13

Clinical manifestations

Answer 13

Fever/chills/weakness/fatigue/flu like symptoms

Mortality ass. To glomerulonephritis/valve dysfunction/HF

Question 14

Cardiac lesions histology

Answer 14

Vegetations mitral/aortic valves 
Friable/bulky/destructive to underlying myocardium
Affect RHS HV in IVDU
Single or multiple 
Made of B/PC/platelets/fibrin 
In SLE 50% P have sterile vegetatios

Question 15

Embolic lesions

Answer 15

Friable cardiac lesions that break away and travel to many extra cardiac sites

Question 16

Extra cardiac manifestations

Answer 16

Brain- stroke mycotic aneurysm 
Eye- roths spot
Heart- infected embolus 
Kidney- infarction hematuria 
Spleen- infarction abscess
Finger- splinter Hm
Skin- painful petechia (oslers nodes) purpura (janaway lesions)