Infective endocarditis

Question 1

IE - background

Answer 1

Infection of endocardium; can be acute or subacute

Question 2

IE - risk factors (3)

Answer 2

Children at risk are those with turbulent blood flow through the heart or where prosthetic material has been inserted following surgery: e.g.

1. PDA or VSD;
2. Coarctation of aorta;
3. Previous rheumatic fever.

Question 3

IE - causative agents (3)

Answer 3

The most common pathogens associated with infective bacterial endocarditis
are:
1. Streptococcus viridans (50% cases): often after dental procedures. Also - principal cause in children with congenital heart disease (without previous surgery).
2. Staphylococcus aureus: often related to central venous catheters. Also - common following cardiac surgery and in the presence of prosthetic cardiac and endovascular materials
3. Group D streptococcus (enterococcus): often after lower GI surgery.
An organism is not found in up to 10% of cases.

Question 4

IE - symptoms

Answer 4

1. In the early stage symptoms are mild
2. Prolonged fever persisting over several months may be the only feature
3. Alternatively, rapid onset of high intermittent fever can occur. May have rigors

Non-specific symptoms include:

4. Myalgia and arthalgia;
5. Headache, anorexia, weight loss, night sweats

Question 5

IE - signs/ex

Answer 5

Variable. Classic signs include:

1. Pallor/anaemia. Petechial haemorrhages (why?)
2. Nail bed—splinter haemorrhages. Finger clubbing (late). Tender nodules—fingers/toes (Osler’s nodes); erythematous palms/soles of feet (Janeway lesions)
3. Heart murmurs (change in character with time)
4. Splenomegaly
5. Retinal infarcts (Roth’s spots)

Question 6

IE - ix

Answer 6

1. FBE (raised WCC)
2. ESR (raised)
3. CRP (raised)
4. Repeated blood cultures
5. Echocardiography (needed to look for valve ‘vegetations’)

Question 7

IE - mx (3)

Answer 7

1. Antibiotic therapy: should be started as soon as possible. Delays may result in progressive endocardial damage and deterioration in cardiac function. High dose IV antibiotics (e.g. penicillin/vancomycin) are required for a minimum of 6wks.
2. Bed rest is recommended and heart failure should be treated.
3. Surgery will be necessary for removal of infected prosthetic material.

Question 8

IE - prognosis (3)

Answer 8

1. Even with abx tx, mortality may be as high as 20%
2. Complications (50-60%) include heart failure… (?)
3. Systemic emboli from left-sided vegetations may result in brain abscess and stroke