Endocarditis

Question 1

Infective endocarditis

Answer 1

Infection of the endothelium of the heart valves

Usually affects LHS of heart

Question 2

Predisposing factors

Answer 2

Heart valve abnormalities (EG: calcification)
Prosthetic heart valves
IVDU
Intravascular lines in hospital

Question 3

Pathogenesis

Answer 3

Heart valve damaged
Turbulent blood flow over roughened endothelium
Platelets and fibrin deposited
Organisms settle in the deposits
Bacteraemia
Vegetation (roughening) of heart valves
Vegetations can ‘pop’ off and travel within the blood around the body

Question 4

Common causative organisms

Answer 4

Staph aureus
Strep viridans
Enterococcus sp.
Staph epidermidis

Question 5

Atypical organisms

Answer 5

Don't grow in a blood culture 
Ie: they will be culture -ve 
Bartonella
Coxiella Burnetti
Chlamydia 
Legionella 
Mycoplasma

Question 6

Staph epidermidis

Answer 6

Staph = gram +ve clusters
Coagulase test: -ve
Often a skin contaminant
Often leads to false positive results as skin hasn’t been sterilised properly before cultures obtained
Common in endocarditis involving metals/plastic (e.g.: prosthetic valve - only if less than 2 months post surgery)

Question 7

Investigations

Answer 7

Echo:
Trans-thoracic Echo
Trans-oesophogeal Echo (if high suspicion after TTE)

3 blood cultures (1 hr apart before starting antibiotics):

• if all 3 are +ve then good evidence of endocarditis
• if only 1 is +ve then it could be a contaminant (e.g. stoph epidermidis)
• if all 3 are -ve then consider serology for atypical organisms

Question 8

Indicators that suggest there is endocarditis

Answer 8

Two separate +ve blood cultures
Echo evidence
New valvular regurgitation 
Predisposing factors 
Recent dental work

Question 9

Acute endocarditis common causative organism

Answer 9

Staph aureus

Question 10

Sub-acute endocarditis common causative organism

Answer 10

Strep viridans

Question 11

IVDU endocarditis common causative organism

Answer 11

Staph aureus

Commonly affects tricuspid valve as this is where blood returning to the heart drains to first

Question 12

Signs of endocarditis

Answer 12

Splinter haemorrhages
Osler's nodes
Janeway lesions 
Clubbing
Roth spots (eyes)
New murmur
Bilateral basal creps
Weight loss
Splenomegaly

Question 13

Symptoms

Answer 13

Fever
Sweats
Rigors
Malaise

Question 14

General Management

Answer 14

IV antibiotics for roughly 6 weeks

Don’t give prophylaxis antibiotics

Question 15

Staph aureus endocarditis management

Answer 15

IV Flucloxacillin

acute, IVDU

Question 16

Strep viridans endocarditis management

Answer 16

IV Gentamicin
IV Benzylpenicillin

(sub-acute, dental procedures)

Question 17

Dental procedures causative organism

Answer 17

Strep Viridans

Question 18

Less than 2 months after prosthetic valve surgery causative organism

Answer 18

Staph epidermidis