Infective endocarditis

Question 1

What is infective endocarditis?

Answer 1

Infection of the heart valves or other endocardial lined structures within the heart (such as septal defects, pacemaker leads, surgical patches)
Quite rare - 6 per 100,000.

Question 2

Who are most likely to get IE?

Answer 2

• Those who have abnormal valve already (regurgitant or prosthetic) are most likely
• Introduction of infectious material into the blood stream or directly to heart during surgery
• Have had previous IE
• Anyone can get it however
• Used to be a disease of the young by rheumatic heart disease but now it is a disease of
  
  • elderly
  • young i.v drug users - usually right sided as they inject into veins which goes to RA first
  • young with congenital heart disease
  • anyone with prosthetic heart valves

Question 3

Symptoms/Presentation of IE?

Answer 3

1. New or recurrent heart murmur
2. Embolic events of unknown origin
3. Sepsis of unknown origin - very common
4. Fever - most frequent sign of IE and should be suspected if associated with:
   
   • previous history of IE
   • Previous valvular or congenital heart disease
   • Evidence of congestive HF
   • New conduction disturbance

Clinical presentation depends on site and organism causing the infection
- Signs of systemic infection (fever, night. sweats, rigors, malaise, weight loss, anaemia)
- Embolisation (stroke, PE, bone infections, kidney dysfunction, MI)
- Valve dysfunction (arrhythmias)
(fever + new murmur = endocarditis until proven otherwise)

Question 4

Most common causative organisms of IE?

Answer 4

Most common = Streptococci viridans followed by staph aureus, Strep bovis and enterococci.
Rarely HACEK group (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella).

Question 5

What do we use to diagnose IE?

Answer 5

We use the modified Dukes criteria
2 major or 1 major and 3 minor or 5 minor criteria on Dukes criteria.

1. Blood cultures - 3 sets at different times from different sites at peak of fever. (5% are still negative)
2. Echocardiography - TTE showing vegetations or new valve leak. Safe, non-invasive, no discomfort, gives poorer images.
   TOE - gives excellent pictures but more invasive, discomfort for patient, generally safe but risk of aspiration or perforation. We organise TOE if there is still uncertainty after TTE.

Question 6

What peripheral stigmata may be present with IE?

Answer 6

Petechiae 10-15%
Splinter haemorrhages
Osler’s nodes (small, tender purple erythemateous subcutaneous nodules found on hands and feet)
Janeway lesions - haemorrhages on hands and feet
- Roth spots (red spots on fundoscopy exam)

Question 7

What ECG changes might be seen in IE?

Answer 7

• Ischaemia or infarction or new appearance of heart block

- First degree heart block as the vegetation can infect the myocardium and affect the conduction of the heart

Question 8

Treatment of IE?

Answer 8

• Antibiotics for 6 weeks (type of abx depends on infectious agent - see handbook)
• Treat other complications (emboli, arrhythmia, heart failure)
• May require cardiac surgery to remove infectious material and or repair the damage. Operation is needed if the infection cannot be cured with abx, if there are complications or if they have an infected device.

Question 9

Prognosis of IE?

Answer 9

50% require surgery
20% inhospital mortality
15% recurrence at 2 years

Question 10

Prevention of IE?

Answer 10

No longer giving abx prophylaxis to those with valve disease during interventions**
Consider prophylaxis in high risk patients only! (prosthetic valves, previous IE, cyanotic HD)