Infective Endocarditis

Question 1

What is infective endocarditis?

Answer 1

Infection of the endothelium (inner layer) of the heart.

Most commonly affects the heart valves.

Question 2

List three risk factors for infective endocarditis.

Answer 2

• IV drug use
• Structural heart disease
• Chronic kidney disease
• Immunocompromised status
• History of infective endocarditis

Structural heart disease includes valvular disease, congenital disease, hypertrophic cardiomyopathy, prosthetic heart valves, and implantable cardiac devices.

Question 3

What is the most common causative agent of infective endocarditis?

Answer 3

Staphylococcus aureus

Other causes include streptococcus viridans and enterococcus.

Question 4

Name clinical features of infective endocarditis.

Answer 4

• Fatigue
• Fever
• New or ‘changing’ heart murmur
• Splinter haemorrhages
• Janeway lesions
• Osler’s nodes
• Roth spots
• Splenomegaly
• Petechiae
• Finger clubbing

Signs and symptoms include night sweats, muscle aches, and anorexia.

Question 5

What investigations are used to diagnose infective endocarditis?

Answer 5

• Blood cultures
• Transoesophageal echocardiography

Echocardiography may show vegetations on valves.

Question 6

What are the major criteria in the Modified Duke Criteria for diagnosing infective endocarditis?

Answer 6

• Persistently positive blood cultures
• Specific imaging findings (e.g. vegetations)

Diagnosis requires one major and three minor criteria or five minor criteria.

Question 7

Fill in the blank: A fever greater than _____ is a minor criterion for infective endocarditis.

Answer 7

38C

Other minor criteria include predisposition, vascular phenomena, immunological phenomena, and microbiology phenomena.

Question 8

What is the first-line management for infective endocarditis?

Answer 8

IV broad-spectrum antibiotics

Common antibiotics include amoxicillin or gentamicin.

Question 9

How long is the typical duration of antibiotic treatment for infective endocarditis with native heart valves?

Answer 9

4 weeks

Treatment duration is 6 weeks for prosthetic heart valves.

Question 10

List two indications for surgery in the management of infective endocarditis.

Answer 10

• Heart failure relating to valve pathology
• Large vegetations or abscesses
• Infections not responding to antibiotics

Surgery is indicated in severe cases.

Question 11

What complications can arise from infective endocarditis?

Answer 11

• Heart valve damage → regurgitation
• Heart failure
• Emboli → abscesses, strokes, splenic infarction

These complications can significantly impact patient outcomes.