L64 – Infective endocarditis, pericarditis, myocarditis Flashcards Preview

MBBS I CPRS > L64 – Infective endocarditis, pericarditis, myocarditis > Flashcards

Flashcards in L64 – Infective endocarditis, pericarditis, myocarditis Deck (94):
1

What is the definition of infective endocarditis?

Infection of the endocardial surface of the heart

2

Definition of Myocarditis?

Inflammation of the myocardium

3

Definition of Pericarditis?

Inflammation of the pericardium

4

Infective endocarditis requires which 2 components?

Damaged valve

Microorganism

5

What are the 3 steps that results in a damage valve necessary for microbe infection?

1) Valvular endothelium damage
2) Platelet and fibrin deposition
3) Nonbacterial thrombotic endocarditis (NBTE)

6

What are the 3 steps of microorganism invasion leading to bacteremia before adhering to heart valve?

1) Microbe from muscous membrane or colonized tissue
2) Cause trauma to mucosa or colony tissue
3) Penetrate into blood stream > Bacteremia

7

What does bacteria in blood stream adhere to to cause infective endocarditis?

Bacteria adhere to Nonbacterial thrombic endocarditis valve

8

Do microbes adhere to healthy heart valves?

No

9

What is the MoA of bacteria after adhering to heart valve?

1) Colonization:

2) Mature vegetation

10

What are some bacterial virulence factors that can cause trauma to mucosa?

Bacteriocins (toxins)
IgA Proteases

11

What are the 3 general factors that can cause valvular endothelium damage?

Trauma
Turbulence
Metabolic changes

12

What processes allow bacteria adhered to heart valve to gain protection from neutrophils?

- Increase bacteria division

- Increase secretion of extracellular proteases

- Increase deposition/aggregation of fibrin and platelet

13

Describe the mature vegetation in IE?

-Dense aggregate of microorganisms

-Platelet rich thrombus

-Inflammatory leukocytes

14

What are some congenital conditions that predisposes to IE?

Septal defects
>> Atrial / ventricular septal defects


Valvular defects
>> Mitral / tricuspid valvular defects

15

What are some acquired conditions that predispose to IE?

 Degenerative

 Rheumatic heart disease

 Prosthetic valve

 Previous endocarditis

16

List some non-specific, systemic clinical representations of IE?

Fever
Weight loss
Malaise
Night sweat
Clubbing

17

Name 2 clinical representations of damaged valve in IE?

New/ changing murmur

Heart failure (caused by mitral/ aortic/ tricuspid regurgitation...etc)

18

What are some Emboli/ metastatic infections caused by IE?

OSSMM

Osteomyelitis
Spenomagaly/ splenic infarct
Stroke**
Myocardial infarction
Mycotic aneurysm

19

How does IE lead to stroke?

Dislodged damaged valve/ vegetation >> emboli >> stroke

20

How does IE cause mycotic aneurysm?

NOT fungus

Bacteremia infect blood vessels and cause area of vessel weakness > form bulge > aneurysm

21

Name one immunological complication of IE?

Glomerunephritis

22

Upon physical inspection, what are some classical signs of IE?

Janeway's Lesion
Splinter haemorrhage
Osler nodes
Roth spots

23

Which of the classical signs of IE are immunological related, which are vascular related?

Janeway's Lesion = vascular phenomenon

Osler's nodes and Roth's spots are immunological phenomenon

24

What are some endogenous origins of infective organisms for IE?

Endogenous:
Dental
GI tract
Genito-urinary tract

25

What are some EXOgenous origins of infective organisms for IE?

Skin
IV catheters (e.g. drug addict)
Cardiovascular devices (e.g. pacemakers)

26

What are the 3 most important characteristics of bacteria that causes IE?

-Serum resistance (can survive in blood)

-Ability to Adhere to valve surface or platelet-fibrin thrombus

-Resist host defense inside vegetation

27

What is THE MOST COMMON pathogen that causes IE on a Native heart valve (not prosthetic)? What is the natural reservoir in humans?

Staphylococcus aureus

Skin, thus can enter blood stream via wound on skin

28

Name the 5 classes of pathogens that most commonly cause IE to native heart valves?

Staphylococcus
Viridans
S.Bovis
Enterococci
Fastidious gram negative bacilli (HACEK)

29

What is the most important pathogen to cause IE on prosthetic heart valves?

Coagulase negative Staphylococcus

30

What are the 2 most important Fastidious gram negative bacilli (HACEK) that cause IE on native valves?

Eikenella corrodens

Kingella kingae/ Kingella denitrificans

31

How is Eikenella corrodens transmitted to cause IE?

Oral flora into exposed skin wound

(e.g. punch someone in the face )

32

Kingella kingae/ Kingella denitrificans most commonly affect what age group?

Children

33

What are the 3 pathogens that come from animal contact and can cause IE?

Brucella spp.
Bartonella henselae (Cat scratch disease)
Coxiella burnetti (Q fever)

34

What is the most common streptococcus to cause native valve IE?

Viridans streptococci

35

How could colon cancer lead to IE?

Cause normal flora - Strep. Bovis - to enter blood stream

36

Where is coagulase negative Staphylococcus found in body?

Skin normal flora

37

Compare the pathogen that causes early (within 60 days to 12 months) and late prosthetic valve endocarditis?

Early = coagulase-negative Staphylococcus

Late = Staph. aureus

38

What is the gold standard/ definitive diagnosis of IE?

- Histology/ culture of vegetation or intracardiac abscess

- Evidence of lesions: vegetation or intracardiac abscess showing active endocarditis on histology

39

What is the clinical criteria for IE?

Duke's criteria

Meet 2 major criteria,
I major and 3 minor
5 minor

40

What are the 2 major criteria in Duke's criteria for IE?

**B& E** in a Mad VIP Fight

Blood cultures positive for IE (proof of bacteremia)

Evidence of endocardial involvement (observation of vegetation)

41

What are the minor criteria of Jone's criteria for IE?

B& E in a **Mad VIP Fight**

MVIPF

-Predisposition (e.g IV use, heart condition)

-Fever

-Vascular phenomena

-Immunological phenomena

-Microbiological evidence that do not meet a major criteria

42

List some immunological phenomenon in the minor criteria of Jone's criteria?

glomerulonephritis,
Osler’s nodes,
Roth’s spots,
Rheumatoid
factor

43

list some Vascular phenomenon in the major criteria of Jone's criteria?

mycotic aneurysm,
intracranial hemorrhage, conjunctival hemorrhage, Janeway lesion, MI, stroke, splenic infarct

44

What is considered a blood culture positive result for IE? (2)

Microbes typical in IE are identified from:

a) 2 SEPARATE blood cultures

b) PERSISTENTLY POSITIVE blood cultures

45

What is the time span for collecting blood to prove persistently positive blood cultures?

2 or more blood cultures drawn at least 12 hours apart

Majority (e.g. 3/4) cultures of blood positive

46

Can normal blood culture be used to identify Coxiella burnetii?

Need single blood culture
or
use IgG antibody titer for *** Q fever Phase 1 antigen *** (>1:800)

47

Is worsening or changing of preexisting murmur a major criteria for Jone's criteria? If not, what should be the correction?

No

New valvular regurgitation = major criteria

(evidence of endocardial involvement)

48

What are the 3 evidences of endocardial involvement (major criteria) in Jones?

CT, echo, regurg

New valvular regurgitation

Echocardiogram positive for IE

Definitive paravalvular lesions by cardiac CT

49

What features of IE can be seen on echocardiogram?

Intracardial abscess

Partial dehiscence (loose) of prosthetic valve

Pendulum-like intracardiac mass

50

If the blood culture results are 1 positive and 5 negative, does this contribute to the Jone's Criteria for IE?

Yes

As a minor criteria: Positive blood culture but does not meet a major criterion

51

What are the 3 ways to determine causative organism after determining IE?

Culture
Serology
PCR

52

Serolgy for IE pathogen is used for which two pathogens in particular?

Coxiella burnetii (Q fever)

Bartonella henselae (cats)

53

Why is multiple blood cultures required in IE?

To prove continuous bacteraemia

54

Why is skin disinfection necessary before betting blood sample for IE?

remove contamination by skin flora

(e.g. coagulase-negative Staphylococcus,
Corynebacterium, Bacillus, Propionibacterium acnes)

55

What is the procedure of taking blood sample *for IE suspected*?

*which disinfectants, when, how many samples, time between samples, volume of sample*

Iodophore + 70% alcohol

Wait at least 1.5 minutes after disinfection, always before taking any antibiotic

3 sets of blood cultures at different sites, at least 1 hour apart

10ml per bottle

56

What is the function of blood culture bottles?

Nutrients, Dilute antibiotics and natural inhibitory factors

Prevent clotting

Have anaerobic or aerobic bottles

57

2 things not to do when obtaining blood samples?

Change needle prior to inoculating blood culture bottles

Draw blood from Intravascular cathether

58

When do you draw blood from intravascular catheter?

Suspect infection is catheter-related

59

What are the 4 causes of Culture negative endocarditis?

DANI

1) Prior antibiotics before culture
2) Inadequate blood sample

3) Difficult to grow organism

4) Non-infective cause (e.g. cancer, autoimmunity)

60

List the organisms for IE that are difficult to culture?

HACEK (Fastidious gram negative bacilli e.g. Eikenella corrodens, Kingella Kingae)

Brucella

Mycoplasma

Q fever (Coxiella burnetti)

61

2 options for treating IE?

Antibiotics

Surgery

62

Requirements for antiobiotics to treat IE?

Bactericidal, high dose, 4-6 weeks (long duration)

63

Why is IE so hard to treat with antibiotics?
3 reasons

Bacteria protected from exposure to antibiotics or phagocytes due to BIOFILM

Bacteria has redeced cell division

High bacteria load inside vegetation

64

Name the antibiotic for Viridans Streptococci?

Penicillin

65

Antibiotic for Methicillin sensitive Staph. aureus?

Cloxacillin

66

Antibiotic for Methicillin resistant Staph. aureus?

Vancomycin

67

Antibiotic for Enterococcus ?

For Ampicillin sensitive enterococci:

Ampicillin and Gentamicin
or
Ampicillin and Ceftriaxone

68

Antibiotic for coagulase negative staph. on prosthetic valves?

Rifampicin
(to penetrate biofilm)

69

What is the rationale of antibiotic prophylaxis and who is it offered to?

Reduce bacterial load in the blood

Offer to patients with:
1) Risk of underlying heart abnormalities
2) Risk of procedure (e.g. surgery is invasive)

70

For antibiotic prophylaxis of IE before procedure/ surgery, what are some principles?

- Think choice of antibiotic, dosage, timing and duration*

CDDT

Choice: cover most probable organism

Duration: cover transient bacteremia

Dosage: minimum inhibitory concentration for most probable organism

Timing: immediately before procedure

71

What are some underlying heart abnormalities that can increase risk of IE?

MOST IMPORTANT:
-Previous IE
-Prosthetic valve replacement

Others:
Mitral valve prolapse
Ventricular septal defect
Rhuematic heart disease
Congenital aortic stenosis

72

What is the UK NICE guideline for prophylaxis for IE?

No prophylaxis

73

What are the clinical features of myocarditis?

Chest pain
Arrhythmia
Congestive HF

74

What are some sources of infection causing myocarditis and pericarditis?

Adjacent organs
Hematogeneous

75

What is the inflammation of myocardium or pericardium due to?

Direct invasion, toxin, or immune mediated

76

What are the top 3 most common viruses that cause Myocarditis?

Enterovirus - EV71, Coxsackie, Echovirus

Respiratory virus - Adenovirus, influenza virus

Exanthems: mumps, measles, rubella

77

Name 2 bacteria that can cause myocarditis?

Corynbacterium diphtheriae

Borrelia burgdoferi (Lyme's disease)

78

Name 3 parasites that can cause Myocarditis?

Trypanosoma cruzi

Trichinella spp (wild boar)

Toxoplasma gondii (cat, raw beef)

79

Name a fungus that can cause myocarditis?

Dimorphic fungi

80

Aim of myocarditis / pericarditis investigations?

 To confirm the diagnosis of myocarditis / pericarditis

 To exclude non-infective cause

 For infective cases, to find the etiological organism

81

What are some clinical diagnosis results for myocarditis?

*think ECG, echo, blood test*

Increase cardiac enzymes (creatine kinase, troponin)

ECG: non-specific changes

Echocardiogram: Global abnormality

82

Compare the abnormalities seen in echocardiogram in Myocarditis and IE?

Myocarditis = global abnormality

IE = local

83

Myocarditis microbiological diagnosis should be tailoured according to which factors?

according to the patient’s history (e.g. travel, raw food)

physical examination

investigation result

84

What microbiological test is used to differentially diagnose Myocarditis caused by rheumatic fever??

Rheumatic fever: antistreptolysin O titer (ASOT)

85

What microbiological test is used to differentially diagnose Myocarditis caused by respiratory viruses?

nasopharyngeal aspirate (NPA)

>>direct immunofluorescence / PCR

86

What microbiological test is used to differentially diagnose Myocarditis caused by enteroviruses?

throat swab, rectal swab / stool > culture / PCR

87

What microbiological test is used to differentially diagnose Myocarditis caused by respiratory, enteroviruses?

paired serum for serological studies (antibodies)

88

What are the treatment options for myocarditis?

Specific treatment for microorganisms

Manage congestive HF

Bed rest

89

What are the clinical features of Pericarditis?

Chest pain (worse when breathing, swallowing or supine)

Pericardial rub and effusion

Cardiac tamponade

90

What are the viruses that can cause Pericarditis?

Very similar to myocarditis

Respiratory viruses
Enteroviruses
Exanthems

91

What are some bacteria and other pathogens that can commonly cause pericarditis?

 Gram-positive: Staphylococcus aureus, Streptococcus

 Gram-negative: Enterobacteriaceae, Haemophilus influenzae, Neisseria meningiditis

 Fungi (especially dimorphic)
 Parasites

92

What are the clinical exam results for pericarditis?

ECG: Diffuse ST elevation (concave up)

Echo: normal (unless pericardial effusion is involved)

93

What are the gold standard tests for pericarditis?

Pericardial biopsy
Pericardiocentesis

94

What are the similarities and differences between the treatment of pericarditis and myocarditis?

Similar :
Both need bed rest, specific treatment for microbes

Difference:
-Myocarditis need management of congestive HF

-Pericarditis need NSAID and Drainage of pericardial fluid/ Pericardectomy

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