Infective endocarditis

Question 1

What is rheumatic fever?

Answer 1

A disease which occurs after a group A streptococcal infection

Question 2

What bodily features are affected by rheumatic fever?

Answer 2

heart, skin, joints and CNS

Question 3

How long is the latent period before the streptococal infection onset?

Answer 3

2-6 weeks

Question 4

What is the genetic tissue biotype that puts someone at risk of rheumatic fever?

Answer 4

HLA DR4

Question 5

What do repeated streptococcal infections do to the immune system?

Answer 5

They cause an exaggerated B lymphocyte response.

Question 6

What pathogenesis occurs with rheumatic fever?

Answer 6

• Vasculitis affecting connective tissue
• Aschoffs body consists of an aggregate of large cells with polymorphs and basophils around a vascular fibrinoid core
• Pancarditis = inflammation of the heart tissues
• Erythema marginatum
• Subcutaneous nodules
• Chorea

Question 7

What are the main symptoms of rheumatic fever?

Answer 7

• Polyarthritis
• Carditis: pericarditis, myocarditis, endocarditis
• Chorea (involuntary muscle movement)
• Subcutaneous nodule
• Erythema marginatum

Question 8

Is infective endocarditis caused by bacteria or fungi?

Answer 8

Bacteria

Question 9

Why is infective endocarditis on the rise?

Answer 9

1) Increasing number of elderly
2) More invasive procedures introducing infection
3) Increased number if children with congenital heart disease survive
4) Increase in intravenous drug abuse

Question 10

What are the two things which cause endocarditis?

Answer 10

1) Abnormal cardiac endothelial which facilitates bacterial growth
2) Micro-organisms in the blood

Question 11

How does infective endocarditis spread?

Answer 11

Abnormal endothelium creates non-laminar blood flow promoting fibrin and platelet deposition.

This leads to small thrombi developing. The small thrombi allows organisms to adhere and grow.

This leads to characteristic infected vegetations.

Question 12

What are the two main bacterial species that cause infective endocarditis?

Answer 12

Streptococci and Staphylococci

Question 13

What are the early and late clinical features of endocarditis?

Answer 13

Early = fever, sweats, loss of appetite, weight loss, malaise 
Late = splenomegaly, clubbing, anaemia

Question 14

What are the signs of embolism?

Answer 14

Embolism = blocking of a blood vessel

Septic arthritis, osteomyelitis, splenic abscess

CNS - meningitis, ciliary brain abscess, TIA, stroke

Question 15

What are the investigations for suspected infective endocarditis?

Answer 15

1) Urine Test : looking for presence of bacteria
2) Blood culture
3) Blood Investigations
4) Chest radiographs
5) Electrocardiogram
6) Echocardiogram

Question 16

How is endocarditis treated?

Answer 16

Bactericidal antibiotics for 4-6 weeks

Surgery may be needed: extensive damage to valve, infection of prosthetic material, worsening renal failure, persistent infection, embolisation, large vegetations

Question 17

When does the prognosis of infective endocarditis worsen?

Answer 17

• Organism cannot be identified
• Cardiac failure is present
• Infection occurs on a prosthetic valve
• Micro-organisms found are resistant to therapy

Question 18

What patients are at risk of infective endocarditis?

Answer 18

• Adults and children with structural cardiac defects
• Acquired valvular heart disease with stenosis or regurgitation
• Hypertrophic cardiomyopathy
• Previous infective endocarditis
• Structural congenital heart disease
• Valve replacement