Cardio - IE

Question 1

What is infective endocarditis?

Answer 1

• Microbial infection of a native or prosthetic heart valve or mural endocardium.
• leading to the formation of vegetations and tissue destruction.
• Multisystem disorder caused by haematogenous spread

Question 2

What are the risk factors for endocarditis?

Answer 2

1. Prosthetic heart valves
2. IV drug use
3. Congenital heart disease
4. Previous endocarditis
5. Damaged heart valves

Question 3

What are the clinical manifestations of endocarditis?

Answer 3

1. Non-specific presentation: weight loss, lethargy, fevers.
2. Valvular involvement: New murmur, CCF (valve failure)
3. Bacteraemia: Fever, raised inflammatory markers.
4. Embolic phenomena: Septic emboli (CVA, MI, PE, abdominal viscera ischaemia), peripheral stigmata (Janeway lesions, splinter haemorrhages).
5. Immune-complex formation:
   - Renal (interstitial nephritis and glomerulonephritis).
   - Synovitis
   - Myocarditis
   - Osler nodes (tender)
   - Roth’s spots

Question 4

What are the causative organisms in infective endocarditis?

Answer 4

1. Bacterial
   - S. aureus
   - streptococci
   - enterococci-
   - Gram-negative bacilli- HACEK (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella).
2. Fungal (mainly prosthetic valves).

Question 5

How is endocarditis diagnosed?

Answer 5

Modified Duke criteria

Definite endocarditis:
Two major criteria.
One major criteria + 3 minor criteria.
Five minor criteria.

Possible endocarditis:
One major and one minor.
Three minor criteria.

Major criteria:
[1] Microbiologic data: any of the following
i) Two separate cultures with organisms typically involved in endocarditis:
ii) Single culture of Coxiella burnetii
iii) Bacteria consistent with endocarditis from persistently positive blood cultures:
At least two positive cultures drawn >12 hours apart.
3 of 4 cultures positive, with first and last samples separated by >1 hour apart.
[2] Echocardiographic data: any of the following
i) vegetation or myocardial abscess
ii) new valve regurgitation or dehiscence of prosthetic valve

Minor criteria:
[1] Patient at-risk for endocarditis (defined at top of this chapter).
[2] Temperature >38C.
[3] Vascular phenomena:
Major arterial emboli (e.g. ischemic stroke).
Septic pulmonary emboli.
Janeway lesions.
Conjunctival hemorrhage.
Infectious (mycotic) aneurysm.
[4] Immunologic phenomena:
Glomerulonephritis.
Osler’s nodes.
Positive rheumatoid factor.
[5] Blood culture positivity not reaching the level of a major criterion.

Question 6

How is infective endocarditis treated?

Answer 6

1. Resuscitation
2. Investigations:
   - TTE/TOE
   - ECG
   - bloods inc inflammatory markers and renal function
   - blood cultures (3 sets from different sites)
   - urinalysis
   - CXR
3. ABx - liase with micro, often fluclox and gent.
4. Cardiac surgery:
   - valve failure
   - myocardial abscess or fistula
   - fungal infection
   - high risk of emboli (vegetations >10mm)
   - persistent positive blood cultures despite treatment