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Internal Medicine > JH IM Board Review - Infectious Disease VII > Flashcards

JH IM Board Review - Infectious Disease VII Flashcards

1
Q

Infective endocarditis (IE) - Types:

A
  1. Native valve endocarditis ==> Acute and subacute.
  2. Prosthetic valve endocarditis ==> Early and late.
  3. IVDU-related.
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2
Q

How is IE now classified?

A

BY ORGANISM (rather than the time course of infection).

==> Because the etiologic agent is what determines treatment.

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3
Q

IE - Predisposing factors:

A
  1. Age >60.
  2. Male sex.
  3. Abnormal cardiac anatomy (abnormal heart valve - MVP).
  4. Prosthetic valves.
  5. IVDA.
  6. Poor dentition.
  7. Presence of intravascular device, such as a catheter.
  8. Previous endocarditis.
  9. Hemodialysis.
  10. HIV.
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4
Q

IE - Absence of visible vegetation does NOT …?

A

Exclude Dx.

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5
Q

IE - Systemic emboli are seen in up to …?

A

45% of patients ==> May involve any organ.

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6
Q

IE - Large emboli are common in …?

A

FUNGAL IE.

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7
Q

IE - Immune complex disease:

A

More often in patients with subacute bacterial endocarditis.

  1. Glomerulonephritis.
  2. Roth spots (retinal hemorrhages).
  3. Osler nodes (tender nodules on finger or toe pads).
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8
Q

IE - Culture-negative IE - Etiology:

A
  1. HACEK are now readily cultured with contemporary blood culture systems. 3-5% of native valve infections.
  2. May need to hold blood cultures for 3weeks if organisms such as Bartonella, Brucella are suspected.
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9
Q

Unusual IE organisms:

A
  1. C.burnetii (Q fever) ==> Dx by serology, culture often negative.
  2. Fungi ==> Candida spp. most common, followed by Aspergillus spp.; susceptible hosts include those with history of injection drug use, prosthetic valve recipients, and immunocompromised hosts.
  3. Bartonella, Chlamydia, Legionella, Brucella, Mycoplasma spp. are rare causes of IE.
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10
Q

Prosthetic valves - Early and late IE:

A

EARLY ==> Within 2 months of valve insertion.

LATE ==> Within 12 months after valve insertion.

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11
Q

The risk of prosthetic valve endocarditis is highest in the …?

A

FIRST 6 MONTHS following valve placement.

==> Infections less than 2 months after surgery are often NOSOCOMIAL, although those that occur MORE THAN 2 MONTHS after surgery are more likely to be community-acquired.

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12
Q

MCCs of prosthetic valve IE:

A
  1. S.aureus.
  2. CN staph spp.

==> Viridans group strep spp ==> RARE CAUSE OF EARLY prosthetic IE, but relatively COMMON CAUSE OF LATE prosthetic IE.

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13
Q

Causes of bacterial IE - “Typical”:

A
  1. S.aureus (MC).
  2. Viridans.
  3. Enterococcus.
  4. CN staph.
  5. S.bovis biotype 1.
  6. Other strep spp.
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14
Q

Causes of bacterial IE - “HACEK” group - Other:

A
  1. Haemophilus aphrophilus.
  2. Haemophilus parainfluenza.
  3. Actinobacillus actinomycetemcomitans.
  4. Cardiobacterium hominis.
  5. Eikenella corrodens.
  6. Kingela kingii.
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15
Q

Causes of bacterial IE - Injection drug use:

A
  1. S.aureus (MCC).
  2. Viridans.
  3. Enterococcus.
  4. Pseudomonas.
  5. Candida.
  6. S.epi.
  7. Polymicrobial.
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16
Q

Causes of bacterial IE - Unusual causes:

A

NO DOMINANT ORGANISM:

  1. Candida.
  2. Aspergillus.
  3. Coxiella.
  4. Bartonella.
  5. Chlamydia.
  6. Mycoplasma.
  7. Legionella.
  8. Brucella.
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17
Q

Causes of bacterial IE - EARLY prosthetic valve:

A
  1. S.aureus and CN staph (s.epi) ==> MCC.
  2. Gram (-) bacilli.
  3. Enterococcus.
  4. Diphtherioids.
  5. Fungi.
18
Q

Causes of bacterial IE - LATE prosthetic valve:

A
  1. Viridans group strep, S.aureus.
  2. CN staph.
  3. Gram(-) bacilli.
  4. Enterococcus.
19
Q

IE - Dx - DEFINITE bacterial IE is a …?

A

PATHOLOGIC Dx MADE BY CULTURE CARDIAC TISSUE.

20
Q

IE - Dx - Blood cultures:

A

3 SEPARATE SETS of cultures should be drawn, ideally from 3 different sites.

==> They should also be separated in time, ideally 6 HOURS APART.

21
Q

IE - Dx - TTE:

A

1st step in patients with native valves, no congenital heart disease, and no previous endocarditis.

==> Se = 62%.

==> If intermediate-to-high risk probability of having endocarditis ==> Proceed to transesophageal echo (TEE).

22
Q

IE - Dx - TEE:

A

Can consider as a 1st step in pts with prosthetic valves, congenitl heart disease, and previous endocarditis/valve abnormalities.

==> Sometimes a 1st step in pts with limited transthoracic windows, clear stigmata of endocarditis, and new murmurs.

==> Se = 90-100% in native valve IE. Lower in prosthetic valve IE.

==> A negative TEE does NOT r/o IE.

23
Q

IE - Tx - Principles:

A
  1. Parenteral abx preferred to ensure consistent and therapeutic abx levels.
  2. Extended therapy indicated - Usually 4-6 weeks, depending on the etiologic agent (shorter courses associated with risk of relapse).
  3. Bactericidal abx are preferred to bacteriostatic abx.

==> Abx choice should be guided by culture and sensitivity results.

24
Q

Synopsis of Tx of bacterial IE - Viridans group strep or strep bovis biotype I with PCN MIC <0.12:

A

4 weeks PCN G.

==> If non-severe penicillin allergy use ceftriaxone.

25
Q

Synopsis of Tx of bacterial IE - Viridans group strep or strep bovis biotype I with PCN MIC <0.12 - Comments:

A

2 weeks PCN or ceftriaxone, combined with gentamicin reasonable alternative for select patients with select infections (incl. prosthetic valve infection).

==> Severe PCN allergy ==> Use vanco.

26
Q

Synopsis of Tx of bacterial IE - Viridans group strep with PCN MIC >0.12 and <0.5:

A

4 weeks PCN G or ceftriaxone, combined with gentamicin for first 2 weeks.

27
Q

Synopsis of Tx of bacterial IE - Viridans group strep with PCN MIC >0.12 and <0.5 - Comments:

A

Severe PCN allergy: use vanco.

==> If prosthetic valve infection, use combination therapy for 6 weeks.

28
Q

Synopsis of Tx of bacterial IE - MSSA, native valve, left-sided:

A

4 weeks nafcillin or oxacillin for uncomplicated disease.

For complicated disease ==> 6 WEEKS.

Complicated = Perivalvular abscess, metastatic disease, uncontrolled diabetes.

==> Tx decisions should be individualized.

29
Q

Synopsis of Tx of bacterial IE - MRSA, native valve:

A

4-6 WEEKS vancomycin targeting a trough of 15-20microgram/mL.

30
Q

Synopsis of Tx of bacterial IE - MRSA, native valve - Comments:

A

Complicated infections require at least 6-week course + discussion with infectious diseases and cardiac surgery consultants.

31
Q

Synopsis of Tx of bacterial IE - S.aureus, prosthetic valve:

A

6 weeks therapy with nafcillin or oxacillin or vanco (depending on pathogen and sensitivities) in combination with aminoglycoside for initial 2 weeks and rifampin for 6 weeks after blood cultures have cleared (for S.aureus).

==> EARLY SURGICAL CONSULTATION is advised.

32
Q

Synopsis of Tx of bacterial IE - Enterococcus spp:

A

4-6 weeks ampicillin combined with gentamicin or streptomycin if susceptible.

33
Q

Synopsis of Tx of bacterial IE - Enterococcus spp. - Comments:

A
  1. Must ensure isolate susceptible to both ampicillin and gentamicin.
  2. If PCN allergic, consider desensitization, but if anaphylaxis consider vancomycin.
  3. If aminoglycoside resistance demonstrated ==> pursue combination therapy with ampicillin + ceftriaxone; other antimicrobial resistance is common and should prompt infectious diseases consultation.
34
Q

Synopsis of Tx of bacterial IE - Fungal:

A

Early surgery usually required.

35
Q

Tx of IE - When to consider surgery:

A
  1. Failure of medical therapy (ie persistent bacteremia or fungemia).
  2. Infection with difficult to treat organisms (eg fungal, pseudomonas, brucella.
  3. Major embolic events.
  4. New CHF (+ moderate/severe AR/MR).
  5. Significant valve dysfunction, especially in prosthetic valves.
  6. Paravalvular extension; may be manifested by prolonged fever, aortic valve ring abscess, AV conduction defects, +/- fistulas and mycotic aneurysms.
  7. Prosthetic valve and organisms such as S.aureus, Pseudomonas spp, fungi, and resistant enterococci.
36
Q

Prevention of endocarditis - Prophylaxis:

A

Recommendations were revised in 2007 because the risk of endocarditis from dental procedures is LESS than previously estimated.

==> Proph ONLY to patients with HIGH-RISK cardiac conditions who are undergoing procedures that are likely to cause bacteremia.

37
Q

Procedures likely to cause bacteremia include:

A
  1. Dental procedures that involve manipulation of the gingiva or periapical region of the teeth, or perforation of the oral mucosa (not routine dental cleaning).
  2. Procedures of the respiratory tract that will lead to an incision or Bx of the respiratory mucosa.
  3. GI or GU procedures, only in patients with active GI/GU infections.
  4. Procedures involving infected skin or musculoskeletal tissue.
  5. Cardiac surgery involving placement of prosthetic material.
38
Q

High-risk cardiac conditions include:

A
  1. Prosthetic cardiac valves, bioprosthetic and homograft.
  2. Presence of prosthetic material used for valve repair.
  3. Previous IE.
  4. Unrepaired CCHD, incl. palliative shunts and conduits.
  5. Completely repaired congenital heart defect with prosthetic material or device during the first 6 months after the procedure.
  6. Repaired congenital heart disease with residual defects at the site or next to prosthesis.
  7. Cardiac transplant recipients who develop cardiac valvulopathy.
39
Q

Abx recommendations for IE prevention:

A
  1. Single-dose oral amoxicillin (2g) 30-60min before procedure (clindamycin, clarithromycin, or azithromycin if PCN allergic).
  2. Parenteral alternative: ampicillin 2g IV or IM (cefazolin or ceftriaxone 1g IM or IV are also acceptable).
  3. If patient has a severe PCN allergy and is unable to take oral medications, a single dose of clindamycin (600mg), azithromycin (500mg), or vancomycin (15mg/kg) can be used.
  4. If Bx through active infection, consider vanco if MRSA is a concern.
40
Q

Low-risk patients for whom abx prophylaxis is NOT recommended:

A
  1. MVP.
  2. Bicuspid aortic valve.
  3. Acquired aortic or mitral valve disease.
  4. Pacemakers.
  5. Defibrillators.
41
Q

Low-risk procedures for which endocarditis prophylaxis is NOT recommended:

A
  1. GI endoscopy (except sclerosis or dilatation/ ERCP).
  2. Restorative dentistry.
  3. Gynecologic procedures: vaginal hysterectomy, vaginal delivery, cesarean section.
  4. Cardiac procedures: cardiac catheterization, balloon angioplasty.

Internal Medicine (106 decks)

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