Infective endocarditis (IE)

Question 1

What is infective endocarditis?

Answer 1

infection caused by bacteria that enter the bloodstream and settle in the inner lining of the heart – the endocardium – or the heart valves

Question 2

1) What is the commonest organism for IE?
2) What is the commonest organism for IE if < 2 months post valve surgery?

Answer 2

1) Staphylococcus aureus
2) Staphylococcus epidermidis

Question 3

Name 2 symptoms of IE

Answer 3

• Fever
• Aching joints and muscles
• Chest pains when breathing
• Fatigue
• Flu-like symptoms such as fever and chills
• Night sweats
• Shortness of breath

Question 4

Name 2 signs of IE

Answer 4

• Murmur
• Septic signs i.e. fever, night sweats, rigors, malaise, weight loss
• Microscopic haematuria
• Roth spots (boat shaped retinal haemorrhage with pale centre
• Janeway lesions (painless palmar or plantar macules)
• Osler’s nodes (painful pulp infarcts in fingers or toes)
• Splinter haemorrhages

Question 5

The presence of which 2 symptoms/signs is considered IE until proven otherwise?

Answer 5

Fever + new murmur

Question 6

Name 3 risk factors for developing IE

Answer 6

• Older age: commonest in adults > 60
• Artificial heart valves – germs are more likely to attach to prosthetic heart valves
• Damaged heart valves: conditions i.e. rheumatic fever can damage or scar valves, increasing the risk of infection
• Congenital heart defects
• Skin breaches
• Renal failure
• Immunosuppression
• Implanted heart devices i.e. pacemaker
• Poor dental health
• Long term catheter use

Question 7

1) Name 2 investigations of IE
2) Which of these is the most specific imaging investigation?
3) Which of these is the 1st line imaging investigation?

Answer 7

1) Blood cultures to determine the causative germs, complete blood count, echocardiograms (transoesophageal and transthoracic echo), ECG, chest X Ray
2) Transoesophageal echo
3) Transthoracic echo

Question 8

How is IE treated?

Answer 8

Long term (6 weeks min) IV antibiotics or antifungals – the type of medication depends on the causative agent

Question 9

Name 2 complications of IE

Answer 9

• Heart failure
• Pulmonary embolism
• Stroke
• Heart valve damage
• Mycotic aneurysm
• Abscesses developing in organs i.e. aortic root abscess

Question 10

Does subacute IE most commonly occur on normal valves or prosthetic/abnormal heart valves?

Answer 10

Prosthetic/abnormal valves

Question 11

1) Name 2 indications for surgical repair of heart valves in IE
2) What ECG change can be seen due to an aortic root abscess?

Answer 11

1) Aortic root abscess, haemodynamic instability, severe sepsis despite antibiotics, severe GF, valvular obstruction, infected prosthetic valve, repeated emboli, persistent bacteremia
2) PR prolongation

Question 12

1) What is the empirical antibiotic treatment if IE (2)?
2) What is the antibiotic treatment (2) if MRSA’s cultured, and for how long?
3) What is the antibiotic treatment (3) if there’s prosthetic valve endocarditis?

Answer 12

1) IV amoxicillin and gentamicin
2) IV vancomycin + rifampicin. 4 weeks
3) IV vancomycin, gentamicin, rifampicin

Question 13

What investigation is useful in patients where the diagnosis of prosthetic valve endocarditis remains uncertain following echo?

Answer 13

PET CT scan

Question 14

Infective endocarditis in an IV drug user most commonly affects what valve?

Answer 14

Tricuspid