Infective endocarditis

Question 1

Strongest risk factor for developing endocarditis

Answer 1

Previous episode of endocarditis

Question 2

Patients affected by IE

Answer 2

Previously normal valves (50%, typically acute presentation
- the mitral valve most commonly affected

Rheumatic valve disease (30%)

Prosthetic valves

Congenital heart defects

IVDUs
- typically tricuspid lesion

Question 3

Causes of IE

Answer 3

Staphylococcus aureus

Streptococcus viridans

Coagulase-negative staphylococci such as staphylococcus epidermis

Streptococcus bovis

Question 4

Non-infective causes of endocarditis

Answer 4

SLE (Libman-Sacks)

Malignancy: marantic endocarditis

Question 5

S.aureus

Answer 5

The most common cause of IE

Particularly common in acute presentation and IVDU

Question 6

Strep viridans

Answer 6

Most common in developing countries

Linked with poor dental hygiene or following a dental procedure

Question 7

Coagulase-negative staphylococci

Answer 7

Staphylococcus epidermis

Commonly colonise indewelling lines

Most common cause in patients following prosthetic valve surgery

Question 8

Poor prognostic factors

Answer 8

S.aureus infection

Prosthetic valve

Culture negative endocarditis

Low complement levels

Question 9

Mortality according to organism

Answer 9

Staph 30%

Bowel organisms 15%

Strep 5%

Question 10

Indications for surgery

Answer 10

Severe valvular incompetence

Aortic abscess (often lengthened PR interval)

Resistance to antibiotics

Fungal infections

Cardiac failure refractory to standard medical treatment

Recurrent emboli after antibiotic therapy

Question 11

Diagnosis of IE

Answer 11

Modified Duke criteria

Question 12

IE diagnosed if

Answer 12

Pathological criteria positive or

2 major criteria or

1 major and 3 minor criteria or

5 minoer criteria

Question 13

Pathological criteria

Answer 13

Positive histology or microbiology of pathological material obtained at autopsy or cardiac surgery

Question 14

Major criteria

Answer 14

Positive cultures
- 2 cultures consistent with IE
- persistent bacteraemia from 2 blood cultures taken >12 hours apart
- positive serology for coxiella burnetti, bartonella, or chlamydia psittaci

Evidence of endocardial involvement
- positive echo
- new valvular regurgitation

Question 15

Minor criteria

Answer 15

Predisposing heart condition or IVDU

Microbiological evidence does not meet major criteria

Fever >38

Vascular phenomena

Immunological phenomena

Question 16

Vascular phenomena

Answer 16

Major emboli

Splenomegaly

Clubbing

Splinter haemorrhages

Janeway lesions

Petechaiae or purpura

Question 17

Immunological phenomena

Answer 17

Glomerulonephritis

Osler’s nodes

Roth spots