Infective Endocarditis Flashcards Preview

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Flashcards in Infective Endocarditis Deck (55)
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1
Q

Where can infective endocarditis occur?

A
  • Infection of the inner layer of heart: endocardium
  • Heart valves: native, prosthetic
  • Interventricular septum: septal defect
  • Chordae tendinae
  • Intra-cardiac devices
2
Q

Prognosis and mortality of Infective Endocarditis

A
  • Poor prognosis
  • High mortality

Neither incidence nor mortality have decreased in the past 30 years

3
Q

Incidence features of Infective Endocarditis

A
  • Males have it more than females = >2:1
  • Females have a worse prognosis
  • Around 25%, no underlying structural heart disease
4
Q

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

A
  • 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
Q

Specific predisposing valvular lesions in patients with IE

A

Native valve disease

  • Mitral regurgitation
  • Aortic regurgitation
  • Aortic stenosis
  • Congenital heart disease

Prosthetic valve

6
Q

Non-cardiac risk factors for IE

A
  • 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
Q

Pathophysiology of infective endocarditis

A
  • Adherence + invasion of non-bacterial thrombotic endocarditis = a sterile fibrin-platelet vegetation
  • Mechanical distruption of valve endothelium!
  • Physically normal endothelium - 25% : local inflammation
8
Q

Classification of acute bacteraemia

A
  • Fulminant illness over days/weeks

- Staph aureus

9
Q

Classification of subacute bacteraemia

A
  • Weeks/months

- Streptococci

10
Q

Classification of localisation/intracardiac material

A
  • 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
Q

Mode of acquisition of Infective Endocarditis

A
  • Health care-related: nosocomial/idiopathic, non-nosocomial
  • Community-acquired
  • IVDA (intravenous drug abusers)
12
Q

Features of diagnosis of Infective Endocarditis

A
  • Variable presentation
  • High index of suspicion
  • Bacteraemic episode
  • Non-specific sumptoms: fever, fatigue, malaise
13
Q

Symptoms of Infective Endocarditis

A
  • Fever
  • Weight loss
  • Headache
  • Musculoskeletal pain
  • Altered mentation
  • Murmur
14
Q

Clinical findings of Infective Endocarditis

A

Peripheral stigmata

  • Petechiae
  • Janeway lesions
  • Osler’s nodes
  • Splinter haemorhages
  • Clubbing
  • Neurological manifestations
  • Roth’s spots
  • Splenomegaly or infarct
15
Q

Signs of Infective Endocarditis

A
  • Congestive cardiac failure
  • Embolic phenomena: focal neurological signs, peripheral embolus/ abscess-30%, pulmonary embolus/abscess
  • Vascular/immunological phenomena
16
Q

Vascular/Immunological phenomena signs

A

Immune complex deposition

  • Splinter haemorrhages
  • Vasculitic rash
  • Roth spots
  • Osler’s nodes
  • Janeway lesions
  • Nephritis
17
Q

Features of blood cultures in IE

A
  • Prior to starting antibiotics
  • 3 sets
  • Different sites
  • > 6 hours between
  • Severe sepsis: 2 sets, different sites, within 1 hour
18
Q

Features of Urinalysis in IE

A

Positive blood

19
Q

Features of ECG in IE

A

Conduction delay

20
Q

Features of chest X-ray in IE

A
  • Heart failure

- Pulmonary abscesses

21
Q

Features of Echocardiogram in IE

A
  • Transthoracic (TTE)

- +/- transoesophageal (TOE)

22
Q

Types of microbiology blood cultures in IE

A
  • 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
Q

What blood culture is most common in IE?

A

IE with +ve blood cultures

  • 85% of all IE
  • Streptococci
  • Enterococci
  • Staphylococcus
24
Q

Types of streptococci in +ve blood cultures

A
  • 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
Q

Types of Enterococci in +ve blood cultures

A
  • E. faecalis
  • E. faecium
  • E. durans
26
Q

Types of Staphylococcus in +ve blood cultures

A
  • S.aureus: health care associated IE

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

27
Q

Types of -ve blood cultures in IE

A
  • Prior antibiotic treatment
  • Fastidious organisms
  • Intracellular bacteria
28
Q

Features of prior antibiotic treatment in -ve blood cultures

A
  • 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
Q

Fastidious organisms in -ve blood cultures

A
  • Nutritionally variant streptococci
  • Fastidious gram -ve bacilli ]: HACEK group
  • Brucella
  • Fungi
30
Q

Features of intracellular bacteria in -ve blood cultures

A

5% of all IE

  • Coxiella burnetii
  • Bartonella
  • Chlamydia
  • Serological testing, cell culture, gene amplification, PCR
31
Q

What is the major criteria for Modified Duke Criteria?

A
  • Identifying organism

- Providing evidence of infection anywhere within the heart

32
Q

What is the minor criteria for Modified Duke Criteria?

A

Focus on the endocarditis complex of clinical findings

33
Q

Features of major criteria in Modified Duke Criteria

A

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
Q

Features of minor criteria in Modified Duke Criteria

A
  • Predisposition
  • Fever: >38 degrees celsius
  • Vascular phenomena
  • Immunologic phenomena
  • Microbiological evidence
35
Q

Features of vascular phenomena in minor criteria in Modified Duke Criteria

A
  • Major arterial emboli
  • Septic pulmonary infarcts
  • Mycotic aneurysm
  • Intracerebral haemorrhages
  • Conjunctival haemorrhages
  • Janeway lesions
36
Q

Features of immunologic phenomena in minor criteria in Modified Duke Criteria

A
  • Glomerulonephritis
  • Osler’s nodes
  • Roth spots
  • Rheumatoid fever
37
Q

Features of microbiological evidence in minor criteria in Modified Duke Criteria

A
  • Positive blood cultures: do not meet minor criterion (check)
  • Serological evidence of active infection with organism consistent with IE
38
Q

Treatment for IE

A
  • Surgery
    Antibiotics:
  • Aminoglycosides (synergise with cell wall inhibitors)
  • IV gentamicin + IV amoxicillin (native valves)
  • Gentamicin + vancomycin (native
39
Q

Infection organisms of native valves

A
  • Staphylococci
  • Streptococci
  • HACEK species
  • Bartonella species
40
Q

infection organisms of prosthetic valves

A
  • MSSA
  • MRSA
  • non-HACEK G -ve pathogens
41
Q

Treatment for subacute/chronic native valves

A
  • IV Gentamicin
  • IV Benzylpenicilllin
  • or IV Amoxycillin
42
Q

Treatment for acute native valves

A
  • IV Gentamicin

- IV Flucloxacillin

43
Q

Treatment for prosthetic valves

A
  • Gentamicin
  • IV Vancomycin
  • +Rifampicin
44
Q

How is treatment decided?

A
  • Blood culture positive
  • Antibiotics choice dictated by: micro-organism isolated, Sensitivities, Resistance
  • Close liason with: microbiologist, pharmacist
45
Q

What checks should be performed for continuing treatment?

A
  • Daily: FBC, U+E’s, CRP
  • ECG: 1-2 days
  • Echo: weekly
46
Q

Fungi in IE

A
  • PVE
  • IVDA
  • Immunocompromised
  • Candida
  • Aspergillus
  • Very high mortality >50%
  • Rx: dual anti-fungals, valve replacement, often maintained long term, sometimes for life
47
Q

Complications of Infected Endocarditis/ indications for surgery

A
  • Heart failure
  • Fistula formation
  • Leaflet perforation
  • Uncontrolled infection
  • Abscess formation
  • Atrioventricular heart block
  • Embolism
  • Prosthetic valve dysfunction/dehiscence
48
Q

Other indications for surgery

A
  • Uncontrolled infection
  • Enlarging vegetation
  • Abscess formation
  • Atrioventricular block
49
Q

What is the most severe form of IE?

A

PVE (Prosthetic valve endocarditis)

  • Prevalence: 1-6% of valve prosthesis
  • 10-30% of all cases of IE
50
Q

What is PVE(prosthetic valve endocarditis) associated with?

A
  • Difficulties in diagnosis
  • Difficulty with optimal therapeutic strategy
  • Poor prognosis (20-40% in-hospital mortality)
  • Removal of prosthetic material
51
Q

Features of medical therapy for intracardiac devices

A
  • 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
Q

Features of Prophylaxis in IE

A
  • 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
Q

What are cardiac conditions at highest risk of IE?

A
  • Acquired valvular disease: stenosis, regurgitation
  • Valve replacement
  • Structural congenital heart disease
  • Hypertrophic cardiomyopathy
  • Previous IE
54
Q

When is it okay to offer prophylaxis?

A
  • 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
Q

When is it not okay to offer prophylaxis?

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