Infective Endocarditis (IE)

Question 1

Definition if IE

Answer 1

Infection of endocardium due to causative bacteria & colonizing abnormal endothelium (causing ‘vegetation’)

Question 2

Causes of IE

Answer 2

Bacteria:
S.aureus - MC - intravenous drug use, T2DM, surgery

S. Viridans (gram + alpha haemolytic optochin resistant strep, associated with poor dental hygiene)

S.Bovis (associated with colon cancer), P.aeruginosa

HACEK organisms (gram -, normal flora in mouth/throat)

Question 3

Staph aureus vs strep viridans
Virulence (harmful)?
Found where?
Valves attacked?
Vegetations?
Valve destroyed?
Symptoms onset?

Answer 3

Staph aureus
High
Skin - contracted from IV drug use
Damages & healthy
Large
Yes
Days to weeks - acute

Strep viridans
Low
Mouth
Previously damaged
Small
No
Weeks-months - subacute

Question 4

Risk factors of IE

Answer 4

Male, elderly with prosthetic valves
Young IV drug user
Young with congenital heart defect
Rheumatic heart disease

Question 5

Which valve does IE typically affect more?
In IV drug users what is affected more?

Answer 5

IE typically affects mitral valve (left side)
IV drug users , more so the tricuspid (RHS AV valve)

Question 6

Pathology of IE

Answer 6

Abnormal/damaged endocardium (due to turbulent blood flow) have increased platelet adhesion; bacteria adheres to this +causes vegetations
-typically around valves
-causing regurgitation (therefor aortic + mitral valve sufficiency = increased risk of heart failure)

Question 7

Signs and symptoms of IE

Answer 7

FROM JANE
Fevers
Roth spots (retinal haemorrhage)
Osler nodes (fingers & toes - painful)
Murmur - turbulent flow

Janeway lesions (palms & soles of feet/hands - small & painless)

Anemia

Nail bed/splinter haemorrhage-emboli lodges under finger nails

Emboli (septic) - vegetation detach from valve into blood

Question 8

Diagnosis of IE

Answer 8

ECG (prolonged PR - aortic root abscess)

High ESR/CRP + neutrophilia

ECHO; TOE - more invasive than TTE buy better visual + sensitive + specific (GS)

Blood culture - 3 sites over 24hrs

Duke criteria

Question 9

What is Dukes criteria?

Answer 9

2 major or 1 major + 2 minor

Major:
->2 + blood cultures
-ECHO/TOE shows vegetation

Minor:
-fever - temp>38^
-immunological signs (FROM JANE)
-1+ blood culture
-septic emboli
-RF eg. IV drug use

Question 10

Treatment (medicine)?

Answer 10

Staph aureus - vancomycin + rifampicin (+ gentamicin if prosthetic valves)

Strep viridans- benzylpenicillin + gentamicin

For 4-6 weeks

Question 11

Treatment (surgery)

Answer 11

Remove valve If incompetent + replace with prosthetic

Question 12

Complications of IE

Answer 12

Heart failure, aortic root abscess, septic emboli + sepsis