Endocarditis

Question 1

What parts of the heart can be affected by endocarditis?

Answer 1

Heart valves
Mural endocardium (flesh of heart)
Septum
Intracardiac devices (e.g. pacing wires)

Question 2

What is meant by ‘vegetation’

Answer 2

Vegetation refers to where a thrombus has formed and becomes infected following bacteraemia/fungaemia.

Question 3

What is the most common site to find vegetation?

Answer 3

Heart valves

Question 4

List some risk factors to developing endocarditis?

Answer 4

Bacteraemia
Prosthetic heart valves
Previously damaged heart valves (e.g. congenital heart disease)
Previous infected endocarditis

Question 5

Describe the pathogenesis of endocarditis and sequelae

Answer 5

Infection spreads from vegetation, causing valve failure (e.g. cordae tendinae rupture) leading to heart failure.

Apart from heart failure, endocarditis can progress to systemic sepsis, emboli and infarction.

Question 6

What are the common causative pathogens of endocarditis?

Answer 6

Streptococci viridans
Staph aureus
HACEK group (gram negative)

Question 7

What are the common causative pathogens of natural valve infection?

Answer 7

Staph aureus

Streptococcus pneumoniae

Question 8

What are the common causative pathogens of prosthetic valve infection?

Answer 8

Staph aureus

Staph epidermis

Question 9

What are the classical features of endocarditis?

Answer 9

Splinter haemorrhages
Subconjunctival haemorrhages
Osler’s nodes (immune complex deposition in hands/feet causing painful lumps)
Janeway lesions (abscesses on palms/soles)
Finger clubbing

Question 10

How is endocarditis diagnosed?

Answer 10

Identify pathogen and antibiotic susceptibility through blood cultures
Cultures are taken 3 times to maximise coverage.

Question 11

What is Duke’s criteria >

Answer 11

Method of sussing infective endocarditis.

MAJOR criteria:
Positive blood culture for organism that causes endocarditis
Evidence of endocardial involvement on scans

MINOR criteria:
Predisposition to heart problems
Fever
ECG finding
Undefinitive microbiologic evidence

Definite diagnosis:
2 major
1 major 3 minor
5 minor

Question 12

How is native valve endocarditis treated?

Answer 12

Cover streptococcus pneumoniae and S aureus
IV benzylpenicillin
IV gentamicin

Question 13

How is prosthetic valve endocarditis treateD/

Answer 13

Cover S aureus (MRSA) and CoNS
IV vancomycin
IV gentamicin