Infective Endocarditis

Question 1

def

Answer 1

infection of intracardiac endocardial structures (heart valves)

Question 2

what are the organisms which cause infective endocarditis

Answer 2

1 streptococci (40%)
-streptococcus viridans
-streptococcus bovis
2 staphylococci (35%)
-s. aureus
-s. epidermidis
3 enterococci (20%)
-enterococcus faecalis
4 HACEK

Question 3

in which people would infective endocarditis caused by s. epidermidis be common

Answer 3

IV drug users

Question 4

what does HACEK stand for

Answer 4

rarer causes of infective endocarditis
haemophilus
actinobacillus
cardiobacterium
eikenella
kingella

Question 5

aetiology

Answer 5

1 vegetations form as a result of organisms lodging on the heart valves in bacteraemia
2 vegetations destroy the valve leaflets
3 activation of the immune system causes formation of immune complexes leading to cutaneous vasculitis, glomerulonephritis or arthritis

Question 6

associations/risk factors

Answer 6

1 abnormal valves
-congenital
-post-rheumatic
-calcification
-degeneration
2 prosthetic heart valves
3 turbulent flow (patent ductus arteriosus)
4 recent dental work

Question 7

what would s. bovis be associated with

Answer 7

GI malignancy

Question 8

epi

Answer 8

incidence is 16-22 per million PA (UK)

Question 9

history

Answer 9

1 fevers with sweats/rigors
2 arthralgia/myalgia
3 confusion
4 ask about recent dental surgery or IV drug use

Question 10

examination

Answer 10

1 pyrexia
2 tachycardia
3 signs of anaemia (conjunctival pallor)
4 new regurgitant murmur
5 hand signs

Question 11

which heart valves are most commonly affected in infective endocarditis

Answer 11

mitral> aortic> tricuspid> pulmonary

Question 12

what hand signs are there in infective endocarditis

Answer 12

1 splinter haemorrhages
2 clubbing
3 janeway lesions (painless, palmar)
4 oslers nodes (painful)

Question 13

investigations

Answer 13

1 bloods
-FBC (high neutrophil, normocytic anaemia)
-high ESR + CRP
-rheumatoid factor positive
2 urinalysis
-microscopic haematuria
-proteinuria
3 blood culture
4 echo
-TOE is more sensitive than TTE for detection of endocarditis
5 ECG
-abscesses can cause conduction changes

Question 14

what is TOE

Answer 14

transoesophageal echocardiogram

Question 15

what is the classification used to diagnose endocarditis

Answer 15

Dukes’ classification

Question 16

what are the diagnosing criteria for Dukes’ classification

Answer 16

2 major
1 major + 3 minor
5 minor

Question 17

what are the major Dukes criteria

Answer 17

1 positive blood culture in 2 samples
2 positive echo
-vegatation
-abscess
-prosthetic valve dehiscence (wound rupture along the surgical incision)
-new valve regurgitation

Question 18

what are the minor Dukes criteria

Answer 18

1 pyrexia
2 risk factors (abnormal valves, IV drug use, dental surgery)
3 positive blood culture (but not major)
4 positive echo (but not major)
5 vascular signs

Question 19

management

Answer 19

antibiotics for 4-6wks (>6wks for prosthetic valve endocarditis)
urgent valve replacement if poor response to antibiotics or deterioration

Question 20

what antibiotics are used with clinical suspicion of infective endocarditis

Answer 20

benzylpenicillin + gentamicin

Question 21

what antibiotics are used for streptococci infective endocarditis

Answer 21

benzylpenicillin + gentamicin

Question 22

what antibiotics are used for staphylococci infective endocarditis

Answer 22

oxacillin or vancomycin + clindamycin

Question 23

what antibiotics are used for staphylococci prosthetic valve infective endocarditis

Answer 23

benzylpenicillin + gentamicin

Question 24

what antibiotics are used for enterococi infective endocarditis

Answer 24

ampicillin + gentamicin

Question 25

what antibiotics are used for HACEK infective endocarditis

Answer 25

ceftriaxone or ampicillin

Question 26

when is antibiotic prophylaxis given in infective endocarditis

Answer 26

1 history of infective endocarditis
2 dental procedure (2g oral amoxacillin)
3 prosthetic heart valve replacement

Question 27

complications

Answer 27

1 heart failure
2 renal failure
3 glomerulonephritis
4 arterial emboli from vegetations
5 aneurysms

Question 28

prognosis

Answer 28

fatal if untreated

treated 15-30% mortality