Endocarditis

Question 1

Risk factors of infective endocarditis

Answer 1

• IV drug users
• valvular heart disease
• prosthetic heart valves
• congential heart disease
• implantable cardiac devices e.g. pacemaker
• poor dental hygiene
• immunocompromised
• chronic kidney disease

Question 2

What microorganisms cause infective endocarditis?

Answer 2

• staphylococcus aureus (most common)
• streptococcus epidermidis if <2 months post prosthetic valve surgery
• strep viridans if poor dental hygiene

Question 3

Presentation of endocarditis

Answer 3

• fever
• night sweats
• fatigue
• muscle aches
• janeway lesions
• osler’s nodes
• roth spots
• splinter haemorrhages
• finger clubbing

Question 4

Key examination findings in infective endocarditis

Answer 4

• new or changing heart murmur
• petechiae
• Janeway lesions
• Osler’s nodes
• splinter haemorrhages
• Roth spots
• splenomegaly
• clubbing

Question 5

What are Roth spots?

Answer 5

Haemorrhages on retina seen in fundoscopy
Sign of infective endocarditis

Question 6

What are Janeway lesions?

Answer 6

painless red flat macules on palms and soles of feet

Question 7

What are Osler’s nodes?

Answer 7

tender red/purple nodules on the pads of the fingers and toes

Question 8

What are splinter haemorrhages?

Answer 8

thin red/brown lines along the fingernails

Question 9

Investigations of infective endocarditis

Answer 9

• 3 blood cultures at least 6 hours apart + taken from different sites
• transoesophageal echocardiogram
• CXR
• ECG
• FBCs, U&Es + LFTs

Question 10

What criteria is used to diagnose infective endocarditis?

Answer 10

Modified Duke Criteria

Question 11

What is the Modified Duke Criteria?
What is it used to diagnose?

Answer 11

Infective endocarditis
- one major + there minor criteria OR five minor criteria needed to diagnose
.
Major:
- 2 positive blood cultures collected at least 12 hours apart
- evidence of endocardial involvement e.g. new murmur, vegetation seen on echo, abscess
.
Minor:
- Predispotion
- fever >38°
- vascular phenomena e.g. Janeway lesions, splenic infarction
- immunological phenomena e.g. Osler’s nodes, Roth spots
- microbiological phenomena

Question 12

Management of infective endocarditis

Answer 12

• IV broad spectrum antibiotics e.g. amoxicillin +/- gentamicin
• more specific antibiotic once causative organism identified
• antibiotics continued for 4 weeks or 6 weeks if prosthetic heart valves
• surgery

Question 13

antibiotic treatment of infective endocarditis once causative organism has been identified

Answer 13

• staphylococci: flucloxacillin + gentamicin
• streptococci: IV benzylpenicillin + low dose gentamicin
• enterococci: IV amoxicillin + low dose gentamicin
• vancomycin in penicillin-allergic

Question 14

When might surgery be required in infective endocarditis?

Answer 14

• heart failure relating to valve pathology
• large vegetations or abscesses
• infections not responding to antibiotics
• relapse after optimal medical therapy
• valve obstruction

Question 15

Complications of infective endocarditis

Answer 15

• heart valve damage > regurgitation
• heart failure
• infection + non infective emboli > abscesses, strokes, splenic infarction
• glomerulonephritis > renal impairment

Question 16

What valve is most commonly affected in infective endocarditis?

Answer 16

Mitral valve

Question 17

What valve is most commonly affected in IVDU in infective endocarditis?

Answer 17

Tricuspid valve