Infective Endocarditis

Question 1

Risk factors

Answer 1

Valvular disease - microbes like to stick onto valves that are already damaged

Prosthetic valve

Congenital heart disease

IV drug use

Recent dental or surgical procedure

Question 2

Most common causes

Native valve vs. prosthetic valve

Non- infective

Answer 2

Native valve:

• Staph Aureus (most common)
• Strep Viridans

Prosthetic Valve:
- Staph Aureus (most common): particularly MRSA

Non- infective:
- Libman-Sacks due to SLE

Question 3

Modified Duke Criteria

What counts as a diagnosis?

Answer 3

2 major criteria

1 major criteria with 3 minor criteria

5 minor criteria

Question 4

Major criteria

Answer 4

POSITIVE BLOOD CULTURE
Two positive blood cultures showing typical organisms consistent with infective endocarditis, such as Streptococcus viridans and the HACEK group

Persistent bacteraemia from two blood cultures taken > 12 hours apart

Three or more positive blood cultures where the pathogen is less specific such as Staph aureus and Staph epidermidis

Positive serology for Coxiella burnetii, Bartonella species or Chlamydia psittaci

Positive molecular assays for specific gene targets

ECHOCARDIOGRAM
- Positive echocardiogram (oscillating structures, abscess formation, new valvular regurgitation or dehiscence of prosthetic valves)

• New valvular regurgitation

Question 5

Minor Criteria

Answer 5

Predisposing factor: IV drug use or heart condition

Vascular (Vegetations forming septic emboli)

• Janeway’s Lesion
• Splinter haemorrhages
• Splenomegaly

Immunological (antibodies binding to vegetations and then depositing)

• Roth spots in the eyes
• Osler’s Nodes in the finger pads usually and painful (Ow ow Osler’s Nodes)

Fever >38 deg

Microbiological evidence that doesn’t meet major criteria

Question 6

Initial Blind therapy

Native valve

Pen allergic

Prosthetic Valve

Answer 6

Native valve:
Amoxicillin + ? Gentamicin

Pen allergic:
Vancomycin + ?Gentamicin

Prosthetic valve:
Vancomycin + Rifampicin + ? Gentamicin

Question 7

Staph aureus IE

Native

Pen allergic

Prosthetic

Answer 7

Native: Flucloxacillin

Pen allergic: Vancomycin + Rifampicin

Prosthetic: Flucloxacillin + Rifampicin + ? Gentamicin

Question 8

Strep Viridans

Pen allergic

Answer 8

Benzyl Penicillin

Penallergic: Vancomycin + gentamicin

Question 9

Indications for surgery

Answer 9

Not responding to antibiotics

Severe Valvular disease

Aortic abscess (shown by a prolonged PR interval on ECG)

Heart failure not responding to management