Infective Endocarditis

Question 1

What is the definition of infective endocarditis?

Answer 1

Endovascular infection of cardiovascular structures, usually involving the cardiac valves.

Question 2

What are some risk factors for infective endocarditis?

Answer 2

Abnormal cardiac endothelium:
- Previous rheumatic heart disease
- Congenital heart disease
- Age related valvular degeneration
- Prosthetic heart valve

Organisms in blood:
- PWID
- ICED
- Intravascular lines
- Septicaemia
- Poor dentition and dental infections

Others:
- Age >60 years
- Male sex

Question 3

What are some atypical causes of infective endocarditis?

Answer 3

Coxiella burneti (farmers, aortic valve)
HACEK bacteria (poor dental hygiene)
Brucella (goats)
Fungi (immune-compromised, PWID, IV lines)

Question 4

What is the most common cause of acute infective endocarditis for all groups?

Answer 4

Staph aureus

Question 5

What is the most common cause of subacute infective endocarditis, especially in pre-damaged native valves?

Answer 5

Strep viridans

Question 6

What is the most common cause of infective endocarditis in patients with prosthetic valves?

Answer 6

Staph epidermidis
(infection can be at time of valve insertion or many years later)

Question 7

What most commonly causes infective endocarditis in PWID?

Answer 7

Candida
Staph aureus

(right sided valves usually, especially tricuspid)

Question 8

What are some clinical features of acute infective endocarditis?

Answer 8

Overwhelming sepsis and failure
Usually due to aggressive organisms (eg staph aureus)

Question 9

What are some symptoms of subacute infective endocarditis?

Answer 9

Fever
Malaise
Weight loss
Tiredness
Dyspnoea

Question 10

What are some signs of subacute infective endocarditis?

Answer 10

New/changing heart murmur
Finger clubbing
Splinter haemorrhages
Splenomegaly
Roth spots (red spots on retina)
Janeway lesions (non-tender nodular lesions on palm or sole caused by septic emboli)
Osler nodes (painful, red lesions on palms or sole caused by immune complex deposition)
Microscopic haematuria

Question 11

What are some investigations for infective endocarditis?

Answer 11

ECG
CXR
Blood cultures (at least 3 from different times/sites)
Serology
Transthoracic echocardiogram (1st line imaging)
Transoesophageal echocardiogram (most sensitive test)

Question 12

What criteria is used to diagnose infective endocarditis?

Answer 12

Modified Duke criteria

Question 13

What makes up a definite infective endocarditis score on modified Duke criteria?

Answer 13

Two major criteria
One major + three minor criteria
All five minor criteria

Question 14

What is the empirical treatment for native valve infective endocarditis with severe sepsis (acute)?

Answer 14

IV flucloxacillin

Question 15

What is the empirical treatment for subacute native valve infective endocarditis?

Answer 15

IV amoxicillin and gentamicin

Question 16

What is the empirical treatment for prosthetic valve infective endocarditis?

Answer 16

IV vancomycin and gentamicin
Add rifampicin PO on days 3-5

Question 17

What is the empirical treatment for suspected MRSA infective endocarditis?

Answer 17

IV vancomycin and gentamicin
Add rifampicin PO on days 3-5

Question 18

What is the empirical treatment for infective endocarditis in PWID?

Answer 18

IV flucloxacillin

Question 19

When would prophylaxis for infective endocarditis be recommended?

Answer 19

Not routinely recommended but can be indicated in some cases eg people with prosthetic valve before dental treatment

Question 20

What are some complications of infective endocarditis?

Answer 20

Acute valvular insufficiency causing heart failure
Neurologic complications (eg stroke, abscess, mycotic aneurysm)
Embolic complications causing infarction of kidneys, spleen or lung
Infection (eg osteomyelitis, septic arthritis)