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Cardiology Exam IV > Micro- Infective Endocarditis > Flashcards

Micro- Infective Endocarditis Flashcards

1
Q

Infective endocarditis

A

Infection of the heart chambers or valves (endocardium)

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2
Q

List the 4 Classes of Infective Endocarditis

A

Native Valve Endocarditis NVE
Prosthetic Valve Endocarditis PVE
Health Care Associated Endocarditis HCIE
Intravenous Drug-use Endocarditis IVDU

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3
Q

Two forms of NVE

A

Acute : Involves normal valves. Quick insidious onset.

Subacute: Involves previously damaged valves. Occurs more slowly than acute.

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4
Q

Two forms of PVE

A

Early : Within 60 days

Late: After 60 days

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5
Q

When can we can consider IE Nosocomial (HCIE) ?

A

If the infection occurs 72 hours or more past admission. (If it occurs during the first 72 hours it is likely that the patient had a pre-existing infection)

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6
Q

Mitral valve (only) involvement in IE ?

A

28-45% (Highest)

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7
Q

Tricuspid valve (only) involvement in IE ?

A

0-6%

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8
Q

Aortic valve (only) involvemtn in IE ?

A

5-36 % (2nd most)

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9
Q

Aortic and Mitral Valve involvement in IE ?

A

0-35% Quite common

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10
Q

Pulmonary valve involvement in IE ?

A

Less than one percent

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11
Q

Are the valves damaged before the onset of IVDU endocarditis ? Is onset acute or subacute ?

A

No, they are healthy.

Acute

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12
Q

List causes for damage to valves that would predispose someone to a sub-acute NVE ?

A 
Rheumatic Fever (6%)
Calcific Aortic Valve (50%)
Congenital heart disease (15%)
Ventral Septal Defects
Patent ductus arteriosus
Tetrology of Fallot
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13
Q

Describe the initial steps of infection once the valve surface is disrupted

A

Valve surface disruption –> Platelets and Fibrin adhere (Non-Bacterial Thrombotic Endocarditis) –>Bacteria adhere to NBTE –> Increased build up

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14
Q

Sources of Bacteria that cause IE include :

A

Mouth : Dental work, poor hygiene
Lungs: Pneumonial infections
GI: Gastric procedures (colonoscopy
GU: Catheters etc.

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15
Q

Most likely family of Bacteria to cause IE ?

A

Staphylococci (42% of all IE cases)

Mainly S.aureus (31% of staph cause IE. Most common pathogen overall in IE) but also CoNS species

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16
Q

Streptococci acount for nearly 40% of all IE’s. What species are most prevalent

A

Viridans (17 %)
Enterococci (11 %)
Bovis (7%)

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17
Q

Main pathogen for NVE ?

A

Streptococcus (75%)
Viridans, Bovis, Enterococcus
Staph (25%)
Mainly Aureus

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18
Q

List the three main organisms resonsible for ACUTE NVE ?

A

Staph Aureus (abscess with pus formation)

Strep. Pneumoniae (rapid, heavy immune response)

Strep. Pyogenes ((rapid, heavy immune response)

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19
Q

List the two main groups responsible for SUBACUTE NVE ?

A

Viridans Streptococus

HACEK

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20
Q

Main pathogens associated with PVE

A

Coagulase Negative Staphylococcus (30%)

S. aureus (usually nosocomial as MRSA), mosly Early

Strep (Late PVE )

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21
Q

Which organisms are associated with LATE PVE ?

A

Strep.

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22
Q

Which organisms are associated with early PVE ?

A

CoNS and S.aureus

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23
Q

Most common pathogen associated with IVDU endocarditis ?

A

S. Aureus

Also, involved are :

A,C and G Streptococci
Enterococci
Pseudomonas **
HACEK

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24
Q

Common organisms associated with HCIE (hospital acquired)

A

CoNS
S. aureus
Enterococci
Viridan Strep

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25
Q

Which organisms that cause IE produce Dextran ( a virulence factor that is part of bacterial capsule and helps in adhesion)

A 
Oral Strep
   Mutans
   Bovis
   Mitor
   Sanguis
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26
Q

Which organisms that cause IE produce FIM-A , a virulence factor that mediates attachment to the forming thrombus fibrin/platelet matrices on valves ?

A

Viridans Strep.

Enterococci

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27
Q

Molecules that allow for adhesion of bacteria to NBTE ? (found on/in thrombus)

A

Platelets
Fibrinogen
Lamnin
Type 4 collagen

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28
Q

Platelet aggregation is stimulated by Staph. and Strep species. What does S. aureus bind to to cause this ?

A

Platelet associated Von Willebrand Factor

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29
Q

Coagulase +
Catalase +
Beta Hemolysis
Mannitol Salt +

What is this ?

A

S. Aureus

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30
Q

What are the two major species of CoNS ?

A

S. epidermidis
S. lugdnesis

Coagulase - but Catalase +

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31
Q

S. Abiothrophia, formerly called Nutritionally Variant Strep (NVS) must be cultured within 48 hrs with what factors to remain viable ?

A

L-cysteine and Pyridoxine (B6)

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32
Q

Where in body is S. Abiotrophia a normal fluora ?

A

URT , Urogenital and GI

33
Q

Describe the presentation of S. Abiotrophia in IE

A

Seen in 5%
Indolent (slow moving)
Seen in cases with pre-existing heart disease ( NVE Sub-acute onset)
PRONE TO EMBOLI AND RELAPSE
Higher mortality and morbidity than others

34
Q

Who often presents with Group D Strep (enterococcus) ?

A

Older males who have had Urogenital manipulation
Younger women after obstetrics

NOSOCOMIAL !

35
Q

Why are enterococcus difficult to treat ?

A

Bacterial resistance

36
Q

Lab Testing for Group D Strep

A

6.5% NaCl growth
Bile Esculin +
PYR +

37
Q

What two strep species are PYR + ?

A

Enterococcus (Group D)–> Look for GI issues

S. pyogenes –> Look for rheumatic fever

38
Q

S. mutans is associated with what portion of the body ?

A

Mouth. Forms cavities in teeth

39
Q

S. Mutans is not Group D but is positive for what lab indicator ?

A

growth on Bile Esculin

40
Q

S. bovis is also known as

A

S. gallolyticus

41
Q

S.bovis is Group D, growing on Bile Esculin. however, it will not grow on…

A

6.5% NaCL

42
Q

What should you always check for if you have isolated S.bovis from a heart valve ?

A

Colon cancer or GI lesion !!! (vis versa also0

NF of the GI tract but is released with damage to GI tract.

43
Q

HACEK grow on ….

A

Supplemented Chocolate Agar with supplemented CO2

May also show granular growth in broth

44
Q

Describe the thrombi associated with HACEK organisms

A

Large friable lesion
Throw off frequent emboli
Often develop HCF
Often need valve replacement

45
Q 
H
A
C
E
K
A 
Haemophilus parainfluenzae
Aggregatibacter (Actinomyces and aphrophilus)
Cardiobacterium Hominus 
Eikenella corrodens
Kingella kingae
46
Q

Growth on what agar can differentiate H. Parainfluenzae from influenzae ?

A

Blood agar ( H. influenzae only shows up on Chocolate agar)

47
Q

H. Parainfluenzae is a normal fluora where ?

A

Respiratory system

48
Q

How long do you need to keep cultures of H. Parainfluenzae ?

A

2 weeks

49
Q

Is H. Parainfluenzae Acute or Subacute onset ?

A

Subacute (like all HACEK) , usually occures on previously damaged valves with underlying valvular disease.

50
Q

What species is the most common infectious agent of the HACEK’s ?

A

Aggregatibacter

51
Q

Aggregatibacter is associated with what portion of the body and how long does it take for infection to show ?

A

Mouth
Often seen in periodontal disease.
3 Months

52
Q

What does Aggregatibacter produce that can cause significant mortality ?

A

Significant Embolization !!

53
Q

Cardiobacterium hominus assoiciated IE usually occurs how many months post initial infection ?

A

2-5 months

54
Q

Classic characteristics of Cardiobacterium hominus include

A

Characterized by large vegetations, large vessel emboli

55
Q

What will you/ smell on agar that Eikenella is growing on ?

A

Pitting of the agar

Smell Bleach !

56
Q

Who do you most often see Eikenella IE in ?

A

IV drug users (IVDU)

People who get bit by other people a lot

57
Q

Which presentation is more likely to have PMN’s : Acute or subacute ?

A

Acute

58
Q

Which presentation is more likely to have fibroblasts and evidence of repair?

A

Subacute . Slow onset–> more time for repair

59
Q

Duke Criteria for Definite IE

A

2 major criteria
1 major, 3 minor
5 minor criteria

60
Q

Duke Criteria for Possible IE

A

1 major and 1 minor

3 minor

61
Q

Major Criteria for Duke Scale

A

1.Positive Blood Culture
Typical microorganism for IE from 2 separate
blood cultures
Blood cultures drawn more than 12 hours apart
OR
All of 3 or majority of > 4 separate blood
cultures, with first and last specimens drawn at
least 1 hour apart

Single positive blood culture for Coxiella burnetii 
or antiphase I IgG antibody titer >1:800

2.Evidence of endocardial involvement

62
Q

How many blood culture sets are taken ? How are they done chronologically ?

A

3 (each consisting of two veinipunctures)

Acute: 15 mins apart
Subacute: 24 hrs apart

10 ml of blood:
Venous blood
Inoculate rich liquid medium
Subculture days 1&3
Hold at least 3 weeks
Some organisms require 4 weeks
63
Q

DFA staining of valvular tissue will help to identify which pathogens

A

Tropheryma whippelii
Chlamydia/Chlamydophila
Coxiella burnetti
Legionella

64
Q

What technique is becoming the most effective for identifying organisms as costs for this test go down ?

A

PCR

65
Q

Positive Endocardial involvement (Major criteria) includes :

A

1.Positive echocardiogram for IE
A. Oscillating intracardiac mass on valve or
supporting structures or in the path of regurgitant
jets or on iatrogenic devices in the absence of
an alternative anatomic explanation
B.Abcess
C.New partial dehiscence of prosthetic valve

2.New valvular regurgitation

66
Q

Minor Criteria Include

A 
Predisposition
Fever
Vascular phenomena
Immunologic Phenomena
Microbial Evidence
Echocardiographic evidence
67
Q

Predisposition

A

predisposing heart condition or intravenous drug use

68
Q

Fever

A

temperature > 38.0° C (100.4° F)

69
Q

Vascular phenomena

A

major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway lesions

70
Q

Immunologic phenomena

A

glomerulonephritis, Osler’s nodes, Roth spots, and rheumatoid factor

71
Q

Microbiologic evidence

A

positive blood culture but does not meet a major criterion as noted above¹ or serological evidence of active infection with organism consistent with IE

72
Q

Echocardiographic findings

A

consistent with IE but do not meet a major criterion as noted above

73
Q

Janeway lesions

A

Macular, blanching, nonpainful, erythematous lesions on palms and soles
Bacteria, neutrophilic infiltration
Necrosis, subcutaneous hemorrhage due to septic emboli

74
Q

Splinter hemorrhages

A

Nonblanching, linear reddish-brown lesions found under the nail bed

INDICATIVE OF ENDOCARDITIS !

75
Q

Mycotic Embolism

A

Arterial emboli and ischemia of digits distal to a mycotic aneurysm

Aneurysm forms n the artery

76
Q

Oslers Nodes

A

Painful, violaceous nodules found in pulp
of fingers and toes, more often in
subacute cases of IE

Immune complexes in dermal plexus

77
Q

Roth Spots

A

Exudative,
Edematous
Hemorrhagic
Lesions of the retina

78
Q

Serologies for which two infective diseases may also be positive in cases of endocarditis ( both spirochetes) ?

A

Syphilis

Lyme disease

Cardiology Exam IV (9 decks)

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