Infective endocarditis

Question 1

Most common pathogens in IE?

Answer 1

1- Strep viridans
2- Staph aureus
3-  Enterococci
-Coagulase-negative staphylococci
-Haemophilus parainfluenzae
-Actinobacillus
-Streptococcus bovis
-Fungi
-Coxiella burnetii
-Brucella species

Question 2

Pathophysiology of IE?

Answer 2

Caused after endothelial damage on the valvular region, As a result, platelets and fibrin adhere to the underlying collagen surface and create a prothrombotic milieu. Bacteraemia leads to colonisation of the thrombus and perpetuates further fibrin deposition and platelet aggregation, which develops into a mature infected vegetation.

Question 3

What are acute and subacute types?

Answer 3

Acute is when the infection developed over days to weeks and is caracterised by fever, tachycardia and progressive damage to cardiac tissue.

Subacute is when the infection develops over weeks to months. The patient usually presents with vague and constitutional symptoms.

Question 4

Organisms in native-valve IE?

Answer 4

If non-IV drug users: viridans strep, enterococci, staphylococci.

If IV drug user: most likely RIGHT sided valvular problem so the tricuspid valve mainly but also the pulmonary valve sometimes- staph aureus (60 to 90%), streptococci, gram negative bacilli

Question 5

Prosthetic valve IE types?

Answer 5

Early (developing <1 year post surgery)- Staph aureus or coagulase-negative staphylococci.

Late (developing >1 year post surgery)- same as native valve IE organisms.

Question 6

Symptoms of IE?

Answer 6

fever/chills
night sweats, malaise, fatigue, anorexia, weight loss, myalgias (constitutional)
weakness
arthralgias
headache
shortness of breath

Question 7

Key examination signs in IE?

Answer 7

Splinter haemorrhage
Oslers nodes (painful)
Janeway lesions (painless)
Back pain 
Skin infarcts
Chest pain

MURMUR

Question 8

Risk factors for IE?

Answer 8

Previous history of IE
Prosthetic valve
ICD or cardiac catheters
Valvular surgery or heart surgery
IVDU
Dental procedures

Question 9

Investigations diagnostic in IE?

Answer 9

• Blood cultures (3 sets to be taken 1 hour apart before ABx initiation)
• Echo- TTE / TOE

Other investigations as usual: bloods, urinalysis, ECG

Also consider: complement levels, rheumatoid factor, ESR, MRI, CT

Question 10

Treatment of IE?

Answer 10

• Emperical broad spectrum ABx + analgesia

- Surgery