Infective endocarditis

Question 1

Define infective endocarditis.

Answer 1

· An infection involving the endocardial surface of the heart, including the valvular structures, chordae tendinae and endocardium.

Question 2

What is the most common presentation?

Answer 2

Presentation is often non-specific and most commonly includes fever.

Question 3

What diagnostic criteria is used for IE?

Answer 3

Duke diagnostic criteria.

Question 4

What is the epidemiology of IE?

Answer 4

· Half of patients are over 60 years old.
· More common in men.
· Increasing prevalence due to aging population.

Question 5

What is the pathophysiology of IE?

Answer 5

· Typically develops on the valvular surfaces of the heart, which has sustained endothelial damage secondary to turbulent blood flow.
· As a result, platelets and fibrin adhere to the underlying collagen.
· Bacteraemia leads to colonisation of the thrombus and perpetuates further fibrin and platelets.
· This develops into a mature infected vegetation.
· Acute IE is usually associated with more virulent organisms such as staph aureus.

Question 6

What is the prognosis of IE?

Answer 6

· CHF is the greatest predictor for prognosis.
· Surgery is associated with a lower overall mortality. But these patients often have a high intra-op mortality rate.
· Worsening outcomes due to increased prevalence.
· Older people have a worse prognosis.

Question 7

What is the aetiology for · own valve endocarditis w/out IVDU?

Answer 7

· Viridans group strep.
· Staph aureus.
· Enterococci.

Question 8

What is the aetiology for IVDU’s?

Answer 8

· Staph aureus.
· Strep.
· Gram-negative bacilli.
· Polymicrobial infections.

Question 9

What is the aetiology for prosthetic valve endocarditis?

Answer 9

· Coagulase-negative staph.
· Staph aureus.
· Enterococci.
· Gram-negative bacilli.

Question 10

List the most common risk factors?

Answer 10

· Prior hx of infective endocarditis.
· Presence of artificial prosthetic heart valves.
· Post-heart transplant.
· IVDU.

Question 11

What are the typical presenting signs and symptoms of IE?

Answer 11

FROM JANE:
	· F - Fever.
	· R - Roth spots. 
	· O - Osler's nodes. 
	· M - Murmur (new). 
	· J - Janeway lesions. 
	· A - Anaemia. 
	· N - Nails - splinter haemorrhages.
       · E - Emboli.

Question 12

What investigations would you request if you suspected a patient had IE?

Answer 12

· FBC.
· U&Es and LFTs. 
· Blood cultures.
· ECG. 
· ECHO.

Question 13

How many blood cultures would you request and when for?

Answer 13

3 sets of cultures 1 hour apart prior to starting abx.

Question 14

Suggest some differentials.

Answer 14

· Rheumatic fever - lacks specific vegetations seen with IE.
· Atrial myxoma.
· Libman-Sacks endocarditis. - Hx of SLE.

Question 15

What is are the current treatment options?

Answer 15

· Abx depends on the organism grown.

· Abx: BETA-LACTAM + GENTAMICIN, OR VANCOMYCIN +/- GENTAMICIN or benzylpenicillin.

· Surgery.

Question 16

What complications can occur?

Answer 16

· CHF. Greatest impact on prognosis.

· Systemic embolisation.