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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
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

Cardiology Exam IV (9 decks)

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