Infective Endocarditis and Rheumatic Heart Disease Flashcards

1
Q

What is infective endocarditis?

A

Infection of the endocardium (inner layer of the heart)

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2
Q

What structures might be infected by infective endocarditis?

A

Heart valves
Interventricular septum
Chordae tendinae
Intra-cardiac devices

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3
Q

What is the change in the incidence and mortality of infective endocarditis in the last 30 years?

A

No change in either

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4
Q

What is the general prognosis and mortality of infective endocarditis?

A

Poor prognosis

High mortality

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5
Q

What factors affect the prognosis and morality from infective endocarditis?

A

Underlying cardiac disease
Micro-organism involved
Presence of complications
Patient characteristics

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6
Q

What professions are involved in the collaborative approach to treating infective endocarditis?

A
Primary care physicians 
Acute medicine 
Cardiologists
Surgeons 
Microbiologists
Infectious disease 
Neurologist
Neurosurgeon
Radiologist
Pathologist
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7
Q

What is the incidence of infective endocarditis?

A

3-10 episodes per 100,000 person years in general population
14.5 episodes per 100,000 person years in 70-80 year olds

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8
Q

What is the difference in incidence of infective endocarditis between males and females?

A

Males : females

2:1

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9
Q

Is the prognosis worse in males or females?

A

Females

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10
Q

What percentage of people infected with infective endocarditis will not have an underlying structural heart disease?

A

Around 25%

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11
Q

What are the potential epidemiologies of infective endocarditis?

A
Older patients with degenerative AS 
Rheumatic heart disease 
Health care associated
Invasive procedures
Intra-cardiac devices
Prosthetic valves
Mitral valve prolapse
Bicuspid aortic valve
Congenital heart disease 
IV drug abuse
Immunocompromise
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12
Q

What are the potential pathophysiologies of infective endocarditis?

A

Adherence and invasion of non-bacterial thrombotic endocarditis
Mechanical disruption of valve endothelium

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13
Q

What are the possible causes of mechanical disruption of the valve endothelium?

A
Turbulent blood flow
Electrodes
Catheters
Inflammation
Degenerative changes
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14
Q

What percentage of people with infective endocarditis will have a physically normal endothelium?

A

25%

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15
Q

When might bacteraemia be present in infective endocarditis?

A

Extra-cardiac infections
Invasive procedures e.g. oral, abdominal, genitourinary, intravascular catheters
Gingival disease

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16
Q

How is infective endocarditis classified?

A

Acute, subacute or chronic
Early (< 1 year after surgery) or late (> 1 year after surgery)
Side of infection
Infected devices

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17
Q

What is right sided infective endocarditis associated with?

A

IV drug abusers

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18
Q

What are the presenting features of nosocomial/idiopathic infective endocarditis?

A

Signs and symptoms > 48 hours after hospitalisation

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19
Q

What are the presenting features of non-nosocomial infective endocarditis?

A

Signs and symptoms < 48 hours after hospitalisation plus healthcare contact

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20
Q

What factors might be associated with infective endocarditis?

A

Home-based nursing, IV therapy or haemodialysis < 30 days before onset
Acute care facility < 90 days before onset
Resident in nursing home or long-term care facility
IVDA

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21
Q

What features might suggest infective endocarditis?

A

Variable presentation
High index of suspicion
Bacteraemic episode
Non-specific symptoms e.g. fever, fatigue, malaise

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22
Q

What are the possible signs of infective endocarditis?

A
Congestive cardiac failure 
Vascular or immunological phenomena 
Immune complex deposition
Embolic phenomena 
Focal neurological signs
Peripheral embolus or abscess (30%)
Pulmonary embolus or abscess
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23
Q

What are the signs of immune complex deposition?

A

Vasculitic rash - diffuse, non-blanching, petechial, purpuric
Roth spots - retinal haemorrhages, white/pale centre, coagulated fibrosis
Osler’s nodes - deep red spots, painful, raised, on finger plumps, palms and soles
Janeway lesions - flat, macular, echymotic, on palms and soles, non-tender
Nephritis

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24
Q

What should prompt a high index of suspicion?

A
Fever
New murmur
Pyrexia of unknown origin when other diagnoses have been ruled out
Known IE causative organism isolated in culture 
Prosthetic material 
Previous IE 
Congenital heart disease
New conduction disorder
Immunocompromised
IVDA
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25
Q

When might signs of infective endocarditis be absent?

A

Elderly
After antibiotic treatment
Immunocompromised
IE involving less virulent or atypical organism

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26
Q

What should be done in the investigation of suspected infective endocarditis?

A
Markers of infection/inflammation
FBC
CRP
ESR
U&amp;Es
Blood culture prior to starting antibiotics
Urinalysis 
ECG 
CXR
Echocardiogram
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27
Q

What blood cultures should be taken in the investigation of infective endocarditis?

A

3 sets from different sites with > 6 hours in between

In severe sepsis or septic shock then take 2 sets of bloods from different sites within 1 hour

28
Q

What is the standard echocardiography protocol in infective endocarditis?

A

Transthoracic 1st line imaging
If good quality TTE normal with low clinical suspicion then no TOE needed
If TTE normal with high clinical suspicion then TOE Needed
If TTE or TOE is normal but suspicion of IE remains high, repeat at 7-10 days
If TTE positive then do TOE for complications, abscesses and measuring size of vegetation

29
Q

When should TTE and TOE be repeated?

A
New complication 
New murmur
Persisting fever 
Embolism
Heart failure
Abscess
Atrioventricular block
30
Q

In uncomplicated IE, when is an echo repeated?

A

To assess ongoing treatment for ‘silent’ complications and vegetation size
To assess treatment success on completion - view valve morphology and cardiac function

31
Q

Why might a patient with IE have negative blood cultures?

A

Prior antibiotic treatment
Fastidious organism
Intracellular bacteria

32
Q

85% of all IE patients with positive blood cultures will have one of what three organisms?

A

Streptococci
Enterococci
Staphylococcus

33
Q

What are the streptococci species which might be cultured in IE?

A

Milleri
Anginosus

ORAL;
Sanguis
Mitis
Salivarius
Mutans
Germella
Morbillorum
34
Q

What are the nutritionally variant defective streptococci which have been reclassified and might be cultured in IE?

A

Abiotrophia

Granulicatella

35
Q

What is group D streptococcus associated with?

A

GI tract

36
Q

What are the enterococci species that might be cultured in IE?

A

Faecalis
Faecium
Durans

37
Q

What are the staphylococcal species that might be cultured in IE?

A

Aureus
Coagulase negative
Epidermidis

38
Q

If a blood culture in a patient with suspected IE comes back negative due to prior antibiotic treatment, what is the most likely causative organism?

A

Oral streptococcus or coagulase negative staphylococcus (CNS)

39
Q

What fastidious organisms might cause IE?

A

Nutritionally variant streptococci
Fastidious gram negative bacilli - HACEK group
Brucella
Fungi

40
Q

What percentage of IE is caused by intracellular bacteria?

A

5%

41
Q

What intracellular bacteria might be responsible for IE?

A

Coxiella burnetii
Bartonella
Chlamydia

42
Q

How can intracellular bacteria be identified?

A

Serological testing
Cell culture
Gene amplification
PCR

43
Q

What are the major Duke Criteria?

A

Blood cultures positive for IE

  • typical organisms consistent with IE from 2 separate blood cultures
  • organisms consistent with IE from persistently positive blood cultures
  • single positive blood culture for Coxiella burnetii

Evidence of endocardial involvement

  • positive echocardiogram
  • new valvular regurgitation/murmur
44
Q

What are the minor Duke Criteria?

A

Predisposition

  • predisposing heart condition
  • injection drug use

Fever

Vascular phenomena

  • major arterial emboli
  • septic pulmonary infarcts
  • mycotic aneurysm
  • intracerebral haemorrhage
  • conjunctival haemorrhage
  • Janeway lesions

Immunological phenomena

  • glomerulonephritis
  • Osler’s nodes
  • Roth spots
  • rheumatoid factor

Microbiological evidence

  • positive blood cultures that do not meet major criteria
  • serological evidence of active infection with organism consistent with IE
45
Q

How many Duke Criteria are needed to diagnose IE?

A

Definite:

  • 2 major
  • 1 major and 3 minor
  • 5 minor

Possible:

  • 1 major
  • 3 minor
46
Q

What are the treatment options for IE?

A

Antibiotics
Aminoglycosides
Surgery
Removal of prosthetic material

47
Q

What does the choice of antibiotic for IE treatment depend on?

A
Prior received antibiotics
Native or prosthetic valves
Dates of any surgeries
Knowledge of local epidemiology and antibiotic resistance
Specific culture-negative pathogens
48
Q

What organisms are responsible for native valve IE?

A

Staphylococci
Streptococci
HACEK species
Bartonella species

49
Q

What antibiotic treatment is given for IE of native valves?

A

4 weeks of:
IV gentamicin 1mg 12 hourly and IV amoxicillin 2g 4 hourly

Substitute amoxicillin for vancomycin if penicillin allergic

50
Q

When is IV vancomycin used to treat IE of native valves?

A

If penicillin allergic
Sepsis
MRSA

51
Q

What antibiotic treatment is given for IE of prosthetic valves?

A

6 weeks of:

IV gentamicin and IV vancomycin

52
Q

When is Rifampicin used to treat IE of prosthetic valves?

A

MSSA
MRSA
Non-HACEK G-negative pathogens

53
Q

What are the disadvantages of gentamicin?

A

Nephrotoxic

Ototoxic

54
Q

How is gentamicin dosed?

A

Dosing to actual body weight or ideal body weight if obese

55
Q

What investigations are repeated throughout treatment?

A

Daily FBC, U&Es and CRP
ECG every 1-2 days
Echo weekly

56
Q

What patients are usually affected by fungal IE?

A

PVE
IVDA
Immunocompromised

57
Q

How is fungal IE treated?

A

Dual anti-fungals
Valve replacement
Anti-fungal therapy often maintained long-term, sometimes lifelong

58
Q

What are the complications/indications for surgery in IE?

A
Heart failure 
Fistula formation
Leaflet perforation
Uncontrolled infection 
Enlarging vegetation
Abscess formation 
Atrioventricular heart block
Embolism
Embolism and vegetation > 10 mm
Isolated vegetation > 15mm
Prosthetic valve dysfunction/dehiscence
59
Q

Why might there be an uncontrolled infection?

A
Inadequate antibiotic treatment 
Resistant organisms 
Locally uncontrolled infection
Infected lines
Embolic complications
Extra-cardiac site of infection
Adverse reaction to antibiotics
60
Q

What would indicate an uncontrolled infection?

A

Persistent fever and positive blood cultures after 7-10 days

61
Q

What is the incidence of prosthetic valve endocarditis?

A

1-6% of valve prosthesis

Incidence of 0.3-1/2% per patient per year

10-30% of all cases of IE

62
Q

What is prosthetic valve IE associated with?

A

Difficulties in diagnosis
Difficulties with optimal therapeutic strategy
Poor prognosis
Removal of prosthetic material

Medical therapy alone is associated with high mortality and risk of recurrence

63
Q

What are the cardiac conditions at highest risk of IE?

A
Acquired valvular heart disease e.g. stenosis, regurgitation
Valve replacement 
Structural congenital heart disease
Hypertrophic cardiomyopathy 
Previous IE
64
Q

What percentage of cases of IE are healthcare associated?

A

30%

65
Q

What is the in-hospital mortality of IE?

A

9.6-26%