Infective endocarditis

Question 1

Define:

Answer 1

Infection of the intracardiac structures mainly the heart valves

Question 2

Aetiology:

Answer 2

Mainly strep cocci and aureus

But many other infective organisms

Cause vegetations (deposition of fibrin, platelets and infective organism in times of bacteriemia) which destroy valve leaflets

also can get Libman endocarditis with SLE

Question 3

Risk factors:

Answer 3

IV drug use

recent dental work or poor dental hygiene

prosthetic or abnormal valves

DM

post op wounds

turbulent flow like patent ductus arterisosus

renal failure

Question 4

Epidemiology:

Answer 4

16-22/1 million per year in the UK

Question 5

Symptoms:

Answer 5

FEVER

malaise

weight loss

arthralgia/ myalgia

confusion

skin lesions

Question 6

Signs:

Answer 6

FROM JANE C

pyrexia

new murmur (likely to be LHS)

Janeway lesions - due to emboli deposition

due to immune complex deposition:

• osler nodes
• splinter hameorrhages
• glomerularnephritis
• Roth spots on retina
• Petechiae on pharyngeal and conjunctival mucosa

tachycardia

clubbing

signs of anaemia

Question 7

Investigations:

Answer 7

•	Bloods 
o	FBC - high neutrophils, normocytic anaemia
o	High ESR/CRP 
o	U&Es
o	May be Rheumatoid factor +ve
o	LFTs

Urinalysis
o Microscopic haematuria
o Proteinuria

Blood Culture
o Do 3 sets at different times from different sites are peak of fever

CXR – cardiomegaly

ECG – long PR interval at regular intervals

Echocardiography
o May show vegetation but only if >2mm

Duke’s Classification - a method of diagnosing infective endocarditis based on the findings of the investigations and the symptoms/signs

Question 8

Complications:

Answer 8

• Valve incompetence
• Intracardiac fistulae or abscesses
• Aneurysm
• Heart failure
• Renal failure
• Glomerulonephritis
• Arterial emboli from the vegetations shooting to the brain, kidneys, lungs and spleen

Question 9

management:

Answer 9

• Antibiotics for 4-6 weeks
• Blind therapy of native valve: amoxicillin +/- gentamicin
• Blind therapy or prosthetic valve: vancomycin + gentamycin + rifampicin

• On clinical suspicion = EMPIRICAL TREATMENT
o Benzylpenicillin
o Gentamicin

• SURGERY - urgent valve replacement may be needed if there is a poor response to antibiotics

Question 10

prognosis:

Answer 10

fatal if untreated

15-30% mortality with treatment