Micro- Infective Endocarditis Flashcards Preview

Cardiology Exam IV > Micro- Infective Endocarditis > Flashcards

Flashcards in Micro- Infective Endocarditis Deck (78):
1

Infective endocarditis

Infection of the heart chambers or valves (endocardium)

2

List the 4 Classes of Infective Endocarditis

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

3

Two forms of NVE

Acute : Involves normal valves. Quick insidious onset.

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

4

Two forms of PVE

Early : Within 60 days
Late: After 60 days

5

When can we can consider IE Nosocomial (HCIE) ?

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)

6

Mitral valve (only) involvement in IE ?

28-45% (Highest)

7

Tricuspid valve (only) involvement in IE ?

0-6%

8

Aortic valve (only) involvemtn in IE ?

5-36 % (2nd most)

9

Aortic and Mitral Valve involvement in IE ?

0-35% Quite common

10

Pulmonary valve involvement in IE ?

Less than one percent

11

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

No, they are healthy.
Acute

12

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

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

13

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

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

14

Sources of Bacteria that cause IE include :

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

15

Most likely family of Bacteria to cause IE ?

Staphylococci (42% of all IE cases)

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

16

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

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

17

Main pathogen for NVE ?

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

18

List the three main organisms resonsible for ACUTE NVE ?

Staph Aureus (abscess with pus formation)

Strep. Pneumoniae (rapid, heavy immune response)

Strep. Pyogenes ((rapid, heavy immune response)

19

List the two main groups responsible for SUBACUTE NVE ?

Viridans Streptococus

HACEK

20

Main pathogens associated with PVE

Coagulase Negative Staphylococcus (30%)

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

Strep (Late PVE )

21

Which organisms are associated with LATE PVE ?

Strep.

22

Which organisms are associated with early PVE ?

CoNS and S.aureus

23

Most common pathogen associated with IVDU endocarditis ?

S. Aureus

Also, involved are :

A,C and G Streptococci
Enterococci
Pseudomonas **
HACEK

24

Common organisms associated with HCIE (hospital acquired)

CoNS
S. aureus
Enterococci
Viridan Strep

25

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

Oral Strep
Mutans
Bovis
Mitor
Sanguis

26

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

Viridans Strep.
Enterococci

27

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

Platelets
Fibrinogen
Lamnin
Type 4 collagen

28

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

Platelet associated Von Willebrand Factor

29

Coagulase +
Catalase +
Beta Hemolysis
Mannitol Salt +

What is this ?

S. Aureus

30

What are the two major species of CoNS ?

S. epidermidis
S. lugdnesis

Coagulase - but Catalase +

31

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

L-cysteine and Pyridoxine (B6)

32

Where in body is S. Abiotrophia a normal fluora ?

URT , Urogenital and GI

33

Describe the presentation of S. Abiotrophia in IE

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

Who often presents with Group D Strep (enterococcus) ?

Older males who have had Urogenital manipulation
Younger women after obstetrics

NOSOCOMIAL !

35

Why are enterococcus difficult to treat ?

Bacterial resistance

36

Lab Testing for Group D Strep

6.5% NaCl growth
Bile Esculin +
PYR +

37

What two strep species are PYR + ?

Enterococcus (Group D)--> Look for GI issues
S. pyogenes --> Look for rheumatic fever

38

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

Mouth. Forms cavities in teeth

39

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

growth on Bile Esculin

40

S. bovis is also known as

S. gallolyticus

41

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

6.5% NaCL

42

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

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

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

43

HACEK grow on ....

Supplemented Chocolate Agar with supplemented CO2

May also show granular growth in broth

44

Describe the thrombi associated with HACEK organisms

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

45

H
A
C
E
K

Haemophilus parainfluenzae
Aggregatibacter (Actinomyces and aphrophilus)
Cardiobacterium Hominus
Eikenella corrodens
Kingella kingae

46

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

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

47

H. Parainfluenzae is a normal fluora where ?

Respiratory system

48

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

2 weeks

49

Is H. Parainfluenzae Acute or Subacute onset ?

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

50

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

Aggregatibacter

51

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

Mouth
Often seen in periodontal disease.
3 Months

52

What does Aggregatibacter produce that can cause significant mortality ?

Significant Embolization !!

53

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

2-5 months

54

Classic characteristics of Cardiobacterium hominus include

Characterized by large vegetations, large vessel emboli

55

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

Pitting of the agar
Smell Bleach !

56

Who do you most often see Eikenella IE in ?

IV drug users (IVDU)

People who get bit by other people a lot

57

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

Acute

58

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

Subacute . Slow onset--> more time for repair

59

Duke Criteria for Definite IE

2 major criteria
1 major, 3 minor
5 minor criteria

60

Duke Criteria for Possible IE

1 major and 1 minor
3 minor

61

Major Criteria for Duke Scale

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

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

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

DFA staining of valvular tissue will help to identify which pathogens

Tropheryma whippelii
Chlamydia/Chlamydophila
Coxiella burnetti
Legionella

64

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

PCR

65

Positive Endocardial involvement (Major criteria) includes :

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

Minor Criteria Include

Predisposition
Fever
Vascular phenomena
Immunologic Phenomena
Microbial Evidence
Echocardiographic evidence

67

Predisposition

predisposing heart condition or intravenous drug use

68

Fever

temperature > 38.0° C (100.4° F)

69

Vascular phenomena

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

70

Immunologic phenomena

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

71

Microbiologic evidence

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

Echocardiographic findings

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

73

Janeway lesions

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

74

Splinter hemorrhages

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

INDICATIVE OF ENDOCARDITIS !

75

Mycotic Embolism

Arterial emboli and ischemia of digits distal to a mycotic aneurysm

Aneurysm forms n the artery

76

Oslers Nodes

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

Immune complexes in dermal plexus

77

Roth Spots

Exudative,
Edematous
Hemorrhagic
Lesions of the retina

78

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

Syphilis
Lyme disease