Infective Endocarditis Flashcards Preview

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Flashcards in Infective Endocarditis Deck (55):
1

Where can infective endocarditis occur?

- Infection of the inner layer of heart: endocardium
- Heart valves: native, prosthetic
- Interventricular septum: septal defect
- Chordae tendinae
- Intra-cardiac devices

2

Prognosis and mortality of Infective Endocarditis

- Poor prognosis
- High mortality

Neither incidence nor mortality have decreased in the past 30 years

3

Incidence features of Infective Endocarditis

- Males have it more than females = >2:1
- Females have a worse prognosis
- Around 25%, no underlying structural heart disease

4

Cardiac risk factors for Infective Endocarditis (from most common to least)

- Surgery for prosthetic IE
- Prior native IE
- Cardiac surgery for native IE
- Prosthetic heart valve
- Rheumatic heart disease
- Aortic stenosis
- VSD
- MVP, with mitral regurgitation
- MVP, no murmur

5

Specific predisposing valvular lesions in patients with IE

Native valve disease
- Mitral regurgitation
- Aortic regurgitation
- Aortic stenosis
- Congenital heart disease

Prosthetic valve

6

Non-cardiac risk factors for IE

- Injection drug usage
- Indwelling medical devices
- Diabetes mellitus
- AIDS
- Chronic skin infections, burns
- Alcoholic cirrhosis
- Gastrointenstinal lesions
- Solid organ transplant
- Homeless, body lice
- Pneumonia, meningitis
- Contact with containerised milk or infected farm animals
- Dog/cat exposure

7

Pathophysiology of infective endocarditis

- Adherence + invasion of non-bacterial thrombotic endocarditis = a sterile fibrin-platelet vegetation
- Mechanical distruption of valve endothelium!
- Physically normal endothelium - 25% : local inflammation

8

Classification of acute bacteraemia

- Fulminant illness over days/weeks
- Staph aureus

9

Classification of subacute bacteraemia

- Weeks/months
- Streptococci

10

Classification of localisation/intracardiac material

- Left-sided native valve
- Left-sided prosthetic valve: late >1 year after surgery
- Right-sided
- Device related: PPM, ICD, acute/subacute/chronic, localisation/intracardiac material

11

Mode of acquisition of Infective Endocarditis

- Health care-related: nosocomial/idiopathic, non-nosocomial
- Community-acquired
- IVDA (intravenous drug abusers)

12

Features of diagnosis of Infective Endocarditis

- Variable presentation
- High index of suspicion
- Bacteraemic episode
- Non-specific sumptoms: fever, fatigue, malaise

13

Symptoms of Infective Endocarditis

- Fever
- Weight loss
- Headache
- Musculoskeletal pain
- Altered mentation
- Murmur

14

Clinical findings of Infective Endocarditis

Peripheral stigmata
- Petechiae
- Janeway lesions
- Osler's nodes
- Splinter haemorhages
- Clubbing

- Neurological manifestations
- Roth's spots
- Splenomegaly or infarct

15

Signs of Infective Endocarditis

- Congestive cardiac failure

- Embolic phenomena: focal neurological signs, peripheral embolus/ abscess-30%, pulmonary embolus/abscess

- Vascular/immunological phenomena

16

Vascular/Immunological phenomena signs

Immune complex deposition
- Splinter haemorrhages
- Vasculitic rash
- Roth spots
- Osler's nodes
- Janeway lesions
- Nephritis

17

Features of blood cultures in IE

- Prior to starting antibiotics
- 3 sets
- Different sites
- >6 hours between

- Severe sepsis: 2 sets, different sites, within 1 hour

18

Features of Urinalysis in IE

Positive blood

19

Features of ECG in IE

Conduction delay

20

Features of chest X-ray in IE

- Heart failure
- Pulmonary abscesses

21

Features of Echocardiogram in IE

- Transthoracic (TTE)
- +/- transoesophageal (TOE)

22

Types of microbiology blood cultures in IE

- IE with +ve blood cultures
- IE with -ve blood cultures: prior antibx Rx
- IE with -ve blood cultures: fastidious organisms
- IE with -ve blood cultures: intracellular bacteria

23

What blood culture is most common in IE?

IE with +ve blood cultures
- 85% of all IE
- Streptococci
- Enterococci
- Staphylococcus

24

Types of streptococci in +ve blood cultures

- Oral (viridans) streptococci: S.sanguis, S.mitis, S. salivarius, S. mutans, Germella morbillorum

- S. milleri, S. anginosus group (S.anginosus, S. intermedius, S. constellatus)

- Nutritionally variant 'defective' streptococci recently reclassified: Abiotrophia, Granulicatella

- Group D streptococci: associated with GI tract, streptococcus bovis/equinus complex

25

Types of Enterococci in +ve blood cultures

- E. faecalis
- E. faecium
- E. durans

26

Types of Staphylococcus in +ve blood cultures

- S.aureus: health care associated IE

- Coagulase-negative staph (CNS), S.epidermidis: health care-associated IE

27

Types of -ve blood cultures in IE

- Prior antibiotic treatment
- Fastidious organisms
- Intracellular bacteria

28

Features of prior antibiotic treatment in -ve blood cultures

- Antibiotics given for unexplained fever
- Before blood cultures taken
- Diagnosis of IE not been considered
- Blood cultures may remain negative for many days after discontinuation of antibiotics
- Causative organisms most likely: oral streptococcus,CNS

29

Fastidious organisms in -ve blood cultures

- Nutritionally variant streptococci
- Fastidious gram -ve bacilli ]: HACEK group
- Brucella
- Fungi

30

Features of intracellular bacteria in -ve blood cultures

5% of all IE
- Coxiella burnetii
- Bartonella
- Chlamydia

- Serological testing, cell culture, gene amplification, PCR

31

What is the major criteria for Modified Duke Criteria?

- Identifying organism
- Providing evidence of infection anywhere within the heart

32

What is the minor criteria for Modified Duke Criteria?

Focus on the endocarditis complex of clinical findings

33

Features of major criteria in Modified Duke Criteria

Blood cultures positive for IE
- Typical organism consistent with IE from 2 separate blood cultures
- Organisms consistent with IE from persistently positive blood cultures
- Single +ve blood culture for Coxiella burnetii

Evidence of endocardial involvement
- Positive echocardiogram
- New valvular regurgitation/murmur

34

Features of minor criteria in Modified Duke Criteria

- Predisposition
- Fever: >38 degrees celsius
- Vascular phenomena
- Immunologic phenomena
- Microbiological evidence

35

Features of vascular phenomena in minor criteria in Modified Duke Criteria

- Major arterial emboli
- Septic pulmonary infarcts
- Mycotic aneurysm
- Intracerebral haemorrhages
- Conjunctival haemorrhages
- Janeway lesions

36

Features of immunologic phenomena in minor criteria in Modified Duke Criteria

- Glomerulonephritis
- Osler's nodes
- Roth spots
- Rheumatoid fever

37

Features of microbiological evidence in minor criteria in Modified Duke Criteria

- Positive blood cultures: do not meet minor criterion (check)
- Serological evidence of active infection with organism consistent with IE

38

Treatment for IE

- Surgery
Antibiotics:
- Aminoglycosides (synergise with cell wall inhibitors)
- IV gentamicin + IV amoxicillin (native valves)
- Gentamicin + vancomycin (native

39

Infection organisms of native valves

- Staphylococci
- Streptococci
- HACEK species
- Bartonella species

40

infection organisms of prosthetic valves

- MSSA
- MRSA
- non-HACEK G -ve pathogens

41

Treatment for subacute/chronic native valves

- IV Gentamicin
- IV Benzylpenicilllin
- or IV Amoxycillin

42

Treatment for acute native valves

- IV Gentamicin
- IV Flucloxacillin

43

Treatment for prosthetic valves

- Gentamicin
- IV Vancomycin
- +Rifampicin

44

How is treatment decided?

- Blood culture positive
- Antibiotics choice dictated by: micro-organism isolated, Sensitivities, Resistance
- Close liason with: microbiologist, pharmacist

45

What checks should be performed for continuing treatment?

- Daily: FBC, U+E's, CRP
- ECG: 1-2 days
- Echo: weekly

46

Fungi in IE

- PVE
- IVDA
- Immunocompromised

- Candida
- Aspergillus
- Very high mortality >50%
- Rx: dual anti-fungals, valve replacement, often maintained long term, sometimes for life

47

Complications of Infected Endocarditis/ indications for surgery

- Heart failure
- Fistula formation
- Leaflet perforation
- Uncontrolled infection
- Abscess formation
- Atrioventricular heart block
- Embolism
- Prosthetic valve dysfunction/dehiscence

48

Other indications for surgery

- Uncontrolled infection
- Enlarging vegetation
- Abscess formation
- Atrioventricular block

49

What is the most severe form of IE?

PVE (Prosthetic valve endocarditis)

- Prevalence: 1-6% of valve prosthesis
- 10-30% of all cases of IE

50

What is PVE(prosthetic valve endocarditis) associated with?

- Difficulties in diagnosis
- Difficulty with optimal therapeutic strategy
- Poor prognosis (20-40% in-hospital mortality)
- Removal of prosthetic material

51

Features of medical therapy for intracardiac devices

- Medical therapy alone associated with: high mortality, risk of recurrence
- Removal recommended: proven cases, considered in suspected cases
- Prolonged antibiotic course: IV antibiotics for as long as possible prior to removal, 'sterilise' device/prosthesis

52

Features of Prophylaxis in IE

- Existing evidence does not support the extensive use of antibiotic prophylaxis recommended in previous guidelines

- Prophylaxis should be limited to highest risk patients: highest incidence of IE, highest risk of adverse outcomes from IE

- Indication for antibiotic prophylaxis should be reduced compared to previous recommendations

- Good oral hygiene & regular dental review are of particular importance

53

What are cardiac conditions at highest risk of IE?

- Acquired valvular disease: stenosis, regurgitation
- Valve replacement
- Structural congenital heart disease
- Hypertrophic cardiomyopathy
- Previous IE

54

When is it okay to offer prophylaxis?

- An antibiotic that covers organisms that cause IE
- If a person at risk of IE
- Is receiving antimicrobial therapy
- Due to undergoing a GI or GU procedure
- At a site where there is suspected infection

55

When is it not okay to offer prophylaxis?

- Dental procedures
- Non-dental procedures: upper/lower GI tract, genitourinary tract, upper/lower respiratory tract: ENT, throat procedures, bronchoscopy