Infective Endocarditis

Question 1

What is infective endocarditis?

Answer 1

Infective endocarditis is an infection of the endocardial surface of the heart, including the heart valves.

Question 2

What are the common causative organisms of infective endocarditis?

Answer 2

Staphylococcus aureus, Streptococcus viridans, Enterococcus species, and HACEK organisms.

Question 3

What are the risk factors for infective endocarditis?

Answer 3

Prosthetic heart valves, congenital heart disease, previous endocarditis, intravenous drug use, and immunosuppression.

Question 4

What are the typical symptoms of infective endocarditis?

Answer 4

Fever, night sweats, fatigue, weight loss, malaise, and new or worsening heart murmur.

Question 5

What are the classic signs of infective endocarditis on physical examination?

Answer 5

Janeway lesions, Osler nodes, Roth spots, splinter haemorrhages, and clubbing.

Question 6

What are Janeway lesions?

Answer 6

Non-tender, erythematous macules on the palms and soles caused by septic emboli.

Question 7

What are Osler nodes?

Answer 7

Painful, red, raised lesions on the fingers and toes caused by immune complex deposition.

Question 8

What are Roth spots?

Answer 8

Retinal haemorrhages with a pale centre seen on fundoscopy in infective endocarditis.

Question 9

What is the pathophysiology of infective endocarditis?

Answer 9

Bacteria or fungi adhere to damaged endocardium, forming vegetations composed of microorganisms, fibrin, and platelets.

Question 10

How is infective endocarditis classified?

Answer 10

It is classified as acute (rapid onset, severe symptoms) or subacute (slower onset, milder symptoms).

Question 11

What are the complications of infective endocarditis?

Answer 11

Heart failure, systemic embolism, stroke, renal failure, and abscess formation.

Question 12

What investigations are used to diagnose infective endocarditis?

Answer 12

Blood cultures, echocardiography (transthoracic or transoesophageal), and blood tests (e.g., inflammatory markers).

Question 13

What is the role of blood cultures in diagnosing infective endocarditis?

Answer 13

Blood cultures identify the causative organism and guide antibiotic therapy; at least three sets are required.

Question 14

What is the role of echocardiography in infective endocarditis?

Answer 14

Echocardiography detects vegetations, valvular abnormalities, and complications like abscesses.

Question 15

What are the Duke criteria for infective endocarditis?

Answer 15

Diagnostic criteria including major criteria (positive blood cultures, evidence of endocardial involvement) and minor criteria (e.g., fever, vascular phenomena).

Question 16

How is infective endocarditis treated?

Answer 16

High-dose intravenous antibiotics based on blood culture results, and surgery if indicated (e.g., valve replacement).

Question 17

When is surgical intervention indicated in infective endocarditis?

Answer 17

Persistent infection, heart failure, large vegetations, or complications like abscesses or embolic events.

Question 18

What are the indications for prophylaxis against infective endocarditis?

Answer 18

Patients with prosthetic heart valves, previous endocarditis, or certain congenital heart defects undergoing high-risk dental or surgical procedures.

Question 19

How does intravenous drug use increase the risk of infective endocarditis?

Answer 19

It introduces pathogens directly into the bloodstream, often causing right-sided endocarditis (tricuspid valve).

Question 20

What are splinter haemorrhages, and how are they related to infective endocarditis?

Answer 20

Linear, reddish-brown streaks under the nails caused by microvascular emboli.

Question 21

What is the difference between left-sided and right-sided infective endocarditis?

Answer 21

Left-sided endocarditis affects systemic circulation and organs like the brain, while right-sided endocarditis typically causes pulmonary emboli.

Question 22

What blood test abnormalities are common in infective endocarditis?

Answer 22

Elevated inflammatory markers (CRP, ESR), anaemia, and sometimes abnormal renal function or positive rheumatoid factor.

Question 23

What are HACEK organisms?

Answer 23

A group of fastidious Gram-negative bacteria (e.g., Haemophilus, Aggregatibacter) that can cause infective endocarditis, particularly in prosthetic valves.

Question 24

What is the prognosis of infective endocarditis?

Answer 24

Prognosis depends on early diagnosis and treatment but is poorer in cases with complications or delayed treatment.

Question 25

Why is early recognition of infective endocarditis important?

Answer 25

Early diagnosis and appropriate management reduce the risk of complications like heart failure, embolism, and death.