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Gen Med Unit 7: Cardio > Bacterial Endocarditis > Flashcards

Bacterial Endocarditis Flashcards

1
Q

define bacterial endocarditis

A

Bacterial infection of endocardial surface of heart, commonly involving a heart valve

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2
Q

What does clinical presentation depend on?

A

infecting organism and valve(s) that is/are infected

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3
Q

What is staph aureaus asst with?

A
  1. Staph aureus is most virulent
    A. Asst with acute/short incubation bacterial endocarditis
    B. Affect normal valves
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4
Q

What is strep viridians and enterococci asst with?

A
  1. Asst with subacute/long incubation bacterial endocarditis (SBE)
    A. Usually originate from oral flora
    B. Affect abnormal valves
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5
Q

What are the characteristics of Acute (short incubation) endocarditis?

A 
Fulminant illness
Days to weeks
Aggressive course
Greater virulence
Greater chance for hematogenous spread 
Usually caused by Staph
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6
Q

What are the characteristics of Subacute (long incubation) endocarditis?

A

Low virulence
Progresses slowly over days to months
Low propensity to spread
Usually caused by strep

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7
Q

What are the risk factors for endocarditis?

A 
1. Congenital heart defects
A. VSD
B. Tetrology of Fallot
C. Coarctation of aorta
D. PDA
2. Rheumatic heart disease
3. Bicuspid or calcific aortic valve
4. MVP
5. Hypertrophic cardiomyopathy
6. Prosthetic valves
7. IV drug use
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8
Q

What is the general pathophys of bacterial endocarditis?

A

Development of endocarditis typically requires 2 predisposing conditions
1. Abnormality of endocardium (usually valvular) and bacteremia

  1. Massive bacteremia w/ virulent organism and normal endocardium can also cause endocarditis
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9
Q

Why is bacteremia necessary for endocarditis?

A

Bacteremia delivers organism to surface of valve
Adherence of organism
Invasion of valvular leaflets

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10
Q

What is the common denominator for adherence and invasion of bacteria?

A

sterile fibrin platelet vegetation

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11
Q

What may cause a thrombus to grow in endocarditis?

A
  1. Thrombus may be from
    A. Invading organism
    B. Valvular trauma
    -IV catheters, pacing wires, turbulent blood flow through damaged valve
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12
Q

Where can pathogens travel from to cause bacteremia?

A 
Typically from distant sites
A. Cutaneous abscess
B. Gingivitis
C. UTI
D. Central venous catheter
E. Drug injection site
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13
Q

What is native valve endocarditis caused by?

A 
Caused by pathogens that enter bloodstream
Typical bacteria:
1. Staph aureus
2. Strep gallolyticus
3. Strep viridans
4. Enterocci
5. HACEK organisms
Haemophilus aphrophilus, Aggregatibacter, Cardiobacterium hominis, Eikenella corrodens, & Kingella sp
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14
Q

What is Q fever endocarditis caused by?

A

Coxiella burnetii (rare) causes Q fever endocarditis

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15
Q

What is the leading causative agent for native valve endo?

A

staph aureus
also Leading cause in IV drug abusers
Often involves tricuspid valve

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16
Q

What agents cause prosthetic valve endo within 2 months from valve implantation?

A

Staph epidermidis

Staph aureus

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17
Q

What agents cause prosthetic valve endo more than 2 months from valve implantation?

A

Streptococci most common

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18
Q

What are the sxs of endo?

A 
Signs & sx’s develop over few days (acute) to few weeks (subacute)
Fever & chills
Tachycardia
Night sweats
Fatigability
Malaise
Arthralgias
Development of new or change in existing murmur
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19
Q

What are the characteristic vascular findings for septic emboli in endo?

A 
1. Vascular phenomena: 
A. Petechiae 
-Palate or conjunctiva 
B. Splinter hemorrhages
C. Janeway lesions
-Painless erythematous macules of palms or soles
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20
Q

What are the characteristic immunologic findings in endo?

A
  1. Osler nodes
    A. Painful raised red lesions of fingers, toes or feet
  2. Roth spots
    A. Hemorrhagic lesions with white centers in retina
21
Q

Stroke and major embolic events occur in what % of endo pts? When do they occur?

A
  1. Occur in approx 25% of pts

2. Occur before or within 1st week of antibiotics

22
Q

Always suspect bacterial endocarditis in?

A
  1. Patient w/fever and no obvious source (FUO), especially w/ murmur
  2. (+) blood cultures in pt with valvular abnormality or replacement valve
  3. Hx of invasive procedure
  4. IV drug use
23
Q

What does the FROM JANE pneumonic stand for in endo?

A

Endo sxs:

  1. Fever
  2. Roth’s spots
  3. Osler’s nodes
  4. Murmur
  5. Janeway lesions
  6. Anemia
  7. Nail hemorrhage
  8. Emboli
24
Q

What are the results in in blood cultures in endo pts?

A
  1. Establish diagnosis

2. Three sets of BC at least 1 hr apart before starting abx

25
Q

What are the results in in CXR in endo pts?

A
  1. May show underlying cardiac abnormality

2. +/- pulmonary infiltrates

26
Q

What are the results in in EKG in endo pts?

A
  1. Usually nondiagnostic unless cardiac conduction abnormalities
  2. Suggest myocardial abscess formation
27
Q

What are the results in in ECHO in endo pts?

A
  1. Useful in identifying vegetations

TTE (transthoracic ECHO) has sensitivity 55-65%
TEE (transesopahgeal ECHO) has sensitivity 90%

28
Q

What are the major Duke criteria in indentifying infective endocarditis?

A
  1. (+) Blood Cx
    A. Typical microorganism IE from 2 separate blood cultures
    B. Persistently (+) blood culture
    C. Single (+) blood culture for Coxiella burnetii
  2. Evidence of endocardial involvement
    A. (+) echo for IE
    B. TEE recommended in patients with prosthetic valves
    C. New valvular regurgitation murmur
29
Q

What are the minor Duke criteria in indentifying infective endocarditis?

A
  1. Predisposing heart condition or IV drug use
  2. Fever: 38.0°C (100.4°F)
  3. Vascular phenomena:
    A. Splinter hemorrhages, aneurysm, systemic emboli, pulmonary infarction
  4. Immunologic phenomena:
    A. Glomerulonephritis, Osler’s nodes, Roth spots, (+) RF
  5. (+) microbiologic evidence
30
Q

Whe nis possible dx made?

A

One major & one minor criteria are met OR

Three minor criteria are met

31
Q

When is a definitive dx made?

A

Definitive diagnosis of bacterial endocarditis can be made with 80% accuracy if:
Two major criteria are met OR
One major criteria & 3 minor criteria are met OR
Five minor criteria are met

32
Q

What are complications for endo?

A
  1. damage to heart
  2. site of infection
  3. presence of metastatic foci of infection
  4. Occurrence of embolization
  5. Immunologic mediated processes
33
Q

What are the heart damage criteria that may complicate endo?

A

Destruction of heart valves, myocardial abscesses which can lead to conduction disorders and aneurysms

34
Q

What are the site of infection criteria that may complicate endo?

A

Right side vs left side

Aortic vs mitral

35
Q

What are the occurence of embolism criteria that may complicate endo?

A

Stroke, MI, kidney infarction, splenic infarction

36
Q

When is Abx prophylaxis recommended to prevent endo?

A
  1. Abx prophylaxis for pts with predisposing congenital or valvular anomalies
    A. Dental procedures
    -Strep viridans (alpha-hemolytic streptococci)
    B. Resp tract surgery
    C. Open heart surgery
    D. Surgery for skin infections
    E> Surgery on musculoskeletal tissue
37
Q

Who are high risk pts that need ab prophylaxis?

A
  1. A prosthetic heart valve
  2. Valve repair with prosthetic material
  3. A prior history of IE
  4. Many congenital heart abnormalities (single ventricle, transposition of the great vessels, Tetralogy of Fallot, even if the abnormality has been repaired)
38
Q

Who are moderate risk pts that need ab prophylaxis?

A
  1. Valve repair w/out prosthetic material
  2. Hypertrophic cardiomyopathy
  3. Mitral valve prolapse (MVP) w/valvular regurgitation &/or valvular thickening
  4. Unrepaired ventricular septal defect (VSD), unrepaired patent ductus arteriosus (PDA)
  5. Acquired valvular dysfunction (eg, mitral or aortic regurgitation or stenosis)
  6. Atrial septal defect (ASD), ventricular septal defect (VSD), or PDA closed w/in the past 6 months
39
Q

Who no longer needs abx prophylaxis?

A
  1. prosthetic joint implants

2. Patent foramen ovale (PFO)

40
Q

When is abx prophylaxis administered?

A

All administered 30-60min prior to procedure

41
Q

What is the recommended abx prophylaxis?

A
  1. Amoxicillin 2gm po
  2. Patients allergic to PCN
    A. Clindamycin 600mg po or
    B. Cephalexin (Keflex) 2gm po or
    C. Azithromycin (Zithromax) 500mg po
  3. If IV/IM needed
    A. Ampicillin 2gm or Cefazolin (Ancef) or Ceftriaxone (Rocephin) 1gm
42
Q

How is endo treated empirically?

A

Empiric antibiotics effective against staph, strep and enterococci are recommended:
Vancomycin (Vancocin) 1 g IV q 12 h
+
Ceftriaxone (Rocephin) 2 g IV q 24 h

43
Q

How is treatment changed after C and S come back?

A

IV abx based on C&S for 2-8 weeks

44
Q

What agents can maintain a fever for 9-12 days?

A
  1. Staph aureus or Pseudomonas infection
    A. Repeat BC’s to monitor antibiotic treatment & sterilization of blood. Repeat cultures after pt is off abx for 5-7 days
45
Q

When is surgical treatment indicated for endo pts?

A
  1. In pts who are unresponsive to medical therapy
  2. In pts who have acute heart failure unresponsive to medical therapy
    A. Esp with aortic valve infection
46
Q

Why is anticoagulation contraindicated in native valve endo?

A

Increased risk of intracerebral hemorrhage

47
Q

Why is anticoagulation indicated in prosthetic valve endo?

A

Indicated for pts with prosthetic valve implantation

Anticoagulation is discontinued during septic phase of endocarditis and then restarted after sepsis resolves

48
Q

What is the prognosis for untreated endo?

A

Universally fatal

49
Q

what are the Unfavorable prognostic indicators even when treated?

A
  1. Older age, underlying disorders
  2. Left side worse than right
  3. Resistant organisms
  4. Long delay in treatment
  5. Aortic or multiple valve involvement
  6. Large vegetations
  7. Major embolic events

Gen Med Unit 7: Cardio (13 decks)

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