Infective endocarditis Flashcards Preview

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Flashcards in Infective endocarditis Deck (30):
1

What symptoms when seen together should be treated as infective endocarditis until proven otherwise

Fever + new murmur

2

Which individuals are considered at risk of IE?

1. Past IE
2. Past rheumatic fever
3. IV drug abuser
4. Damaged or replaced valve
5. Structural congenital heart disease
6. Hypertrophic cardiomyopathy

3

In individuals at known risk of IE, what symptom(s) should prompt immediate blood cultures?

Fever lasting >1 week

4

What is infective endocarditis?

An inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves.

5

What is the chief cause of acute IE?

Staph. aureus

6

What are risk factors for acute IE?

Dermatitis
IV injections
Renal failure
Organ transplantation
DM
Post-op wounds

7

What is the usual entry site for the infective agent in acute IE

Skin

8

How does acute IE present?

Acute heart failure with or without emboli

9

How is IE classified?

Acute IE: Occurs on normal valves. Occurs suddenly over days to weeks

Subacute IE: Occurs on abnormal valves. Often due to streptococci of low virulence and causes mild to moderate illness which progresses slowly over weeks and months

10

What are the risk factors for subacute IE?

Aortic or mitral valve disease
Tricuspid valves in IV drug users
Coarctation
Patent ductus ateriosus
VSD
Prosthetic valves

11

How is IE on prosthetic valves classified?

Early: within 60 days of valve surgery; poor prognosis
Late: haematogenous

12

What are the causes of IE?

Bacteraemia
Strep. viridans is a common cause (>35%)
Other causes:
- Enterococci
-Staph aureus/epidermidis
-Diptheroids
-Rarely HACEK gram negative bacteria (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella)

13

What are the main types of signs seen in IE?

Septic signs
Cardiac signs due to cardiac lesions
Immune complex deposition
Embolic phenomena

14

What septic signs are seen in IE?

Fever
Rigours
Night sweats
Malaise
Weight loss
Anaemia
Splenomegaly
Clubbing

15

What signs of cardiac lesions are seen in IE?

Any new murmur or a changing pre existing murmur should raise the suspicion of endocarditis
Vegetations may cause valve destruction and severe regurgitation or valve obstruction
An aortic abscess causes prolongation of the PR interval and may lead to complete AV block
LVF is a common cause of death

16

What signs of immune complex deposition are seen in IE?

Vasculitis
Microscopic haematuria
Glomerulonephritis
Acute renal failure
Roth spots
Splinter haemorrhages
Osler nodes

17

What are Roth spots?

Boat-shaped retinal haemorrhage with pale centre

18

What signs of emboli are seen in IE?

Abscesses in the relevant organ e.g. brain, heart, kidney, spleen or skin- termed Janeway lesions

19

What features are pathognomonic (specific)
for IE

Janeway lesions
Osler's nodes

20

How can you differentiate between Osler's nodes and Janeway lesions?

Osler nodes: painful, usually seen on pads of fingers and toes
Janeway lesions: non-tender, usually seen on the palms or soles of feet

21

What are the diagnostic criteria for IE?

Duke Criteria: 2 major or 1 major and 3 minor or all 5 minor criteria are diagnostic

22

What are the major Duke criteria for IE?

Positive blood culture:
-Typical organism in 2 separate cultures
-Persistently positive blood cultures e.g. 3>12h apart (or majority if ≥4)

Endocardium involved:
-Positive echocardiogram for vegetation, abscess, dehiscence of prosthetic valve
OR
-New valvular regurgitation (change in murmur is not sufficient)

23

What are the major Duke criteria for IE?

Predisposition (cardiac lesion; IV drug abuse)
Fever >38 degrees C
Vascular/immunological signs
Positive blood culture that does not meet major criteria
Positive echocardiogram that does not meet major criteria

24

What is more common, acute or subacute infective endocarditis?

SBE

25

What features might be seen on a blood test in IE?

Normochromic, normocytic anaemia
Neutrophilia
High CRP/ESR

26

What tests should be done to confirm diagnosis of IE?

-Blood cultures: 3 sets at different times from different sites at peak of fever
-Blood tests
-Urinalysis- for microscopic haematuria
-CXR- cardiomegaly
-ECG- long PR interval
- Echo- TTE may show vegetations if >2cm. TOE is more sensitive

27

While awaiting results of blood cultures, which antibiotics should be used for IE?

IV benzylpenicillin and gentamycin

28

What antibiotics should be be given if staphylococcal endocarditis is suspected?

Vancomycin and gentamycin

29

What antibiotics should be be given if gram negative endocarditis is suspected?

Meropenem + vancomycin

30

When should surgery be considered for treatment of IE?

Heart failure
Valvular obstruction
Repeated emboli
Fungal endocarditis
Persistent bacteraemia
Myocardial abscess
Unstable infected prosthetic valve