Block 2 - Endocarditis, Bacteremia, Bone/Joint infection Flashcards

1
Q

Pathophysiology of osteomyelitis (OM)?

A

Hematogenous, vascular insufficiency

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2
Q

Difference between acute, chronic, hematogenous, and contiguous OM?

A

Acute = Sx onset <1wk from infection

Chronic = 10 days to 1 month

Hematogenous = spread through blood

Contiguous = spread through connecting soft tissue

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3
Q

Pathophysiology of diabetic foot osteomyelitis (DFO)?

A

Starts with DFI and contiguous spread

Periosteum is compromised and bone infection

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4
Q

Risk factors of DFO?

A

Deep ulcers

Ulcer that doesnt heal after 6 wks of wound care

Ulcer >2cm

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5
Q

DFO diagnosis?

A

Probe to bone test

ESR, CRP, MRI!

Bone culture (avoid swab if can)

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6
Q

DFO bugs

A

S. aureus

CoNS

GNR and anaerobes (site specific)

Special cases = salmonella and TB

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7
Q

Main DFO treatment?

A

Source control!

Through surgery or non-surgical interventions

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8
Q

When is surgery required for DFO?

A

Gas in deeper tissue

Abscess

Necrotizing fasciitis

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9
Q

When is surgery opted out for DFO?

A

Pt doesnt want amputation

Confined to forefoot and minimal soft tissue loss

Risk > Benefit

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10
Q

Signs of beneficial response for DFO treatment?

A

Decreased ESR, CRP

Radiographic changes that suggest healing

CLEAR MARGINS!!!

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11
Q

If pt is stable with DFO, how do you treat them?

A

Culture it, then surgery

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12
Q

If pt is NOT stable with DFO, how do you treat them?

A

Anti-MRSA + Anti-Pseudomonal

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13
Q

Vertebral OM (VOM) presentation?

A

Back pain

Normal WBC

ESR, CRP elevated

+/- fever

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14
Q

NVO diagnosis?

A

MRI (takes 3-6 wks for bone destruction to show up)

Intraoperative aspiration or biopsy

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15
Q

Risk factors for NVO?

A

Age

IVDU

Indwelling catheter such as HD

Immunocompromised

Bacteremia w/ S. aureus

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16
Q

Which Abx have good bone penetration?

A

Azith
Bactrim
Clinda

Tetra

RFML

Rifampin
Fluoro
Metro
Linezolid

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17
Q

Abx and Sacral OM?

A

Do not give, they only offer transient response

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18
Q

If there is no source control for OM, what is the duration of Tx?

A

6 weeks

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19
Q

When should you suspect prosthetic joint infection (PJI)?

A

SINUS TRACT

persistent wound drainage

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20
Q

Early, delayed, and late PJI

What causes them and what is the time frame?

A

Early and delayed caused by surgery

Late is hematogenous

Early 1-3 months after implantation

Delayed is several months to 1-2 yrs

Late >2 yrs

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21
Q

How is PJI diagnosed?

A

Arthrocentesis (>65% neutro + >1700 leukocytes)

Microbiology (synovial fluid + blood)

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22
Q

PJI bugs?

A

Most common - S. aureus

Then Strep spp., GNR STDs

Least common (special) - arbovirus

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23
Q

PJI Treatment?

A

Source control

2 stage exchange is gold standard in US; 2 surgeries by removing hardware, spacers and Abx, then new hardware

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24
Q

PJI Abx treatment?

A

2-6 wks IV + (Rifampin if hardware is added)

Then 3-6 months PO therapy

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25
Q

Septic arthritis presentation?

A

Painful joint in absence of trauma

Joint motion restriction

Joint warmth

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26
Q

Septic arthritis pathophysiology?

A

Synovial membrane has bugs, pressure from effusions destroy joint cartilage and causes bone loss

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27
Q

Septic arthritis diagnosis?

A

Arthrocentesis (50-200WBC and Glucose <40)

Microbiology

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28
Q

Treatment regimen for septic arthritis?

A

Depends on gram stain

If gonococcal, ceftriaxone 24-48hrs then oral

If not, hold empiric until we can tailor to bug for 3-4 weeks

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29
Q

Bugs for bacteremia?

A

CoNS

HACEK

Haeomphilus spp

Actinobacillus spp

Cardiobacterium spp

Eikenella spp

Kingella spp

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30
Q

G+ MSSA bacteremia, first line Abx?

A

CON

Cefazolin
Oxacillin
Nafcillin

x14 days

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31
Q

MRSA bacteremia, Abx?

A

Uncomplicated: Vanco or dapto (6mg/kg/dose) for at least 2 weeks

Complicated: Same drug but for 4-6 weeks, maybe even higher dapto dose (8-10mg/kg/dose)

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32
Q

What should you rule out with gram + bacteremias?

A

Endocarditis

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33
Q

Bacteremia and vanco use

A

Just make sure MIC≤2, continue using vanco if there is clinical AND microbiological response

If MIC=2, use an alternative

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34
Q

What are the alternative agents for MRSA bacteremia

A

High dose dapto (10mg/kg/day) + one of these agents

Genta
Rifampin
Zyvox
Bactrim
B-lactam (ceftaroline)
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35
Q

What are the CoNS?

A

S. epidermidis (#1 cause), S. hominis, S. lugdenesis

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36
Q

Cefazolin
Oxacillin
Nafcillin

Which one is preferred to treat MSSA?

A

Cefazolin due to ADR and frequency of dosing

37
Q

S. lugdunensis vs other CoNS in bacteremia

A

More virulent

Treatment for minimum of 14 days

38
Q

G+ vs G- bacteremia, which one is more “stickier” to lines and devices?

A

G+

39
Q

Repeated cultures for bacteremia is typically done for (G+/G-)

A

G+, clearance is much faster for G- bacteremia

40
Q

If you see HACEK, rule out…

A

Endocarditis

41
Q

Empiric Tx for G- bacteremia?

A

Ceftriaxone, ceftazidime, cefepime

Zosyn

Carbapenems

May do EIAD for synergy

x7-14 days

42
Q

(G+/G-) bacteremia involves step-down therapy to oral therapy? When are they used?

A

G-

Bacteremia of urinary source (enterobacteriaceae) = Give fluoroquinolones

CAP

or uncomplicated bacteremia

43
Q

What is a biofilm?

A

Surface-associated community of 1+ microbial species attached to each other encased in an extracellular polymeric matrix

Adheres to any surface

44
Q

What is required to diagnose a catheter related bloodstream infection (CRBI)?

A

Positive percutaneous blood culture or multiple catheter sites (both must be of the same organism)

Sign/sx of infection

45
Q

Common bugs for CRBI?

A

Staph, enterococci, GNR (E. coli, kleb.), and Yeast (candida)

S. epidermidis is the most common contaminant (not true infection) and cause of CRBI

46
Q

CRBI empiric Tx?

A

MRSA or Enterococcus = vanco

G- = Ceftazidime, cefepime, carbapenem, B-lactam

Pseudomonas = ceftazidime, cefepime, carbapenem, zosyn

47
Q

How long do you treat CRBI?

A

w/o complications = 7-14 days

Bacteremia or fungemia after catheter removal >72hrs = 4-6 weeks

Endocarditis = 4-6 weeks

48
Q

What bugs would cause you to remove tunneled catheters?

A

S. aureus or Candida

49
Q

MS CONS + CRBI, what are you using?

A

Preferred: Nafcillin or oxacillin

Can use: Cefazolin, Vanco, Bactrim

50
Q

MR CONS + CRBI, what are you using?

A

Preferred: Vanco

Can use: Dapto, Linezolid, ceftaroline

51
Q

How long do you treat MS/MR CONS CRBI?

A

Depends on if catheter is removed or retained

Removed = 5-7 days

Retained = 7-14days

52
Q

MSSA + CRBI, what are you using?

A

Preferred: Nafcillin or oxacillin

Can use: cefazolin, vanco

53
Q

MRSA + CRBI, what are you using?

A

Preferred: Vanco

Can use: dapto, linezolid, ceftaroline, bactrim

54
Q

How long do you treat MSSA/MRSA CRBI?

A

4-6 weeks unless…

diabetic, immunosuppressed, catheter is retained, any prosthetic intravascular device, TEE positive for IE, bacteremia>72hrs, metastatic infection, then its 14 days

55
Q

What to give in the following situations for CRBI

Ampicillin-S Enterococcus

Ampicillin -R, Vanco -S enterococcus

Amp and Vanco -R enterococcus

A

Amp or Amp+Gent

Vanco AND Gent

Dapto or Zyvox

x7-14days

56
Q

How do you treat E. coli or Kleb (ESBL -) CRBI?

A

3rd gen ceph

If ESBL+, use carbapenem

x7-14 days

57
Q

How do you treat APES CRBI?

Acinetobacter

P. aeruginosa

Enterobacter

Serratia

A

Acinetobacter - Unasyn or carbapenem

P. aerugionsa - Ceftazidime, cefepime, carbapenem, zosyn

Enterobacter/Serratia - Carbapenem

x7-14 days

58
Q

Pathophysiology of endocarditis?

A

Endothelial damage to heart; deposition of platelets and fibrin

Forms nonbacterial thrombotic lesion

Presence of bacteremia and bacterial adherence

Persistent growth of bacteria within cardiac lesion and forms infective vegetation

Septic emboli to distant organs

59
Q

Most common bug for endocarditis?

A

S. aureus

60
Q

Most common bug for dental procedures that can cause endocarditis prior to S. aureus?

A

Viridans group Strep

61
Q

Most common bug found in elderly population or homelessness?

A

S. gallolyticus

62
Q

Bug associated w/ GI/GU surgeries?

A

Enterococcus spp.

63
Q

Bug associated w/ prosthetic valve endocarditis?

A

CoNS

64
Q

Which bugs may present as culture negative endocarditis?

A

HACEK organisms

Haemophilus
Actinobacillus
Cardiobacterium
Eikenella
Kingella
65
Q

What are the extra-cardiac complications of endocarditis?

A

Kidneys

Mycotic aneurysms

Skin, eyes, nails

66
Q

Diagnosis of endocarditis?

A

Need clinical, lab, and ECG data

Modified Duke Criteria

Blood cultures (at least 2)

67
Q

TTE and TEE for Endocarditis?

A

TTE used initially or for someone with IVDU

TEE for staph bacteremia and prosthetic heart valves; con = if used initially, they might miss early abscess formation

68
Q

Modified Duke Criteria for endocarditis?

A

Major = 2 positive cultures, evidence via TTE, TEE

Minor = Heart issues, IVDU, Fever >38, immunologic or microbiologic stuff

Definite = 2 major OR 1 major + 3 minor OR 5 minor

Possible = 1 major + 1 minor OR 3 minor

Rejected = alternate diagnosis or resolution <4 days or doesnt meet criteria

69
Q

Staph endocarditis, native valve. Oxacillin-S, Tx?

A

CON

Cefazolin
Oxacillin
Nafcillin

x6 weeks

70
Q

Staph endocarditis, native valve. Oxacillin-R, Tx?

A

Vanco or dapto

x6 weeks

71
Q

Staph endocarditis, prosthetic valve. Oxacillin-S, Tx?

A

Naf or Oxacillin + Rifampin + Genta

≥6wks for the first two rx, gentamicin is for the first 2 wks only

72
Q

Staph endocarditis, prosthetic valve. Oxacillin-R, Tx?

A

Vanco + Rifampin + Genta

≥6wks for the first two rx, gentamicin is for the first 2 wks only

73
Q

Strep endocarditis, native valve. PCN strain MIC ≤0.12, Tx?

A

Pen G x 4wks

Ceftriaxone x 4wks

Pen G + Gent x2wks

Ceftriaxone + Gent x2wks

Vanco x4 wks

74
Q

Strep endocarditis, native valve. PCN strain MIC 0.12-0.5, Tx?

A

Pen G for 4 wks

+

Gent for first 2 wks

or Vanco x4wks

75
Q

Strep endocarditis, native valve. PCN strain MIC≥0.5, Tx?

A

Amp + Gent

Pen + Gent

Vanco

x4-6 wks

76
Q

Strep endocarditis, prosthetic valve. PCN strain MIC≤0.12, Tx?

A

Pen +/- Gent

Ceftriaxone +/-Gent

Vanco

Pen, Ceft, Van x 6 wks
Gent first 2 wks

77
Q

Strep endocarditis, prosthetic valve. PCN strain relatively or fully resistant MIC >0.12 or >0.5mcg/mL, Tx?

A

Pen + Gent

Ceftriaxone + Gent

Vanco

x6 wks

**almost the same as <0.12 but easier to remember

78
Q

Enterococcal endocarditis (regardless of native or prosthetic), susceptible to PCN, gent, and vanco Tx?

A

Amp + Gent (4-6wks)

Pen + Gent (4-6wks)

Amp + ceftriaxone (6wks)

79
Q

Enterococcal endocarditis (regardless of native or prosthetic), susceptible to PCN and vanco, but not to gent Tx?

A

Amp + Strep (4-6wks)

Pen + Strep (4-6wks)

Amp + ceftriaxone (6wks)* same as gent susceptible kind

80
Q

Enterococcal endocarditis, unable to tolerate B-lactams, Tx?

A

Vanco + Gent x 6wks

81
Q

Enterococcal endocarditis, , intrinsic or Beta lactamase producer, Tx?

A

Vanco + Gent

Vanco + Strep

x6wks

82
Q

Enterococcal endocarditis, resistant to PCN, aminoglycosides, and vanco, Tx?

A

Linezolid or Dapto

> 6 wks

83
Q

HACEK endocarditis Tx?

A

Ceftriaxone

Amp

Cipro

4wks for native

6 for prosthetic

84
Q

Culture negative endocarditis, native valve Tx?

A

Vanco + Cefepime

Vanco + Unasyn

x4-6wks

85
Q

Culture negative endocarditis, prosthetic valve Tx?

A

Vanco + Cefepime + Rifampin + Gent

Vanco + Ceftriaxone +/- Rifampin

x 6wks except with gent, its from weeks 2-6

86
Q

Dental procedure prophylaxis, oral Tx?

A

Dosed 30-60 min before procedure

Amox 2g

87
Q

Dental procedure prophylaxis, unable to take oral Tx?

A

Dosed 30-60 min before procedure

Amp, Cefazolin, ceftriaxone

1-2g

88
Q

Dental procedure prophylaxis, allergic to PCN or ampicillin, oral Tx?

A

Dosed 30-60 min before procedure

Cephalexin, Clinda, Clarithromycin, Azithromycin

89
Q

Dental procedure prophylaxis, allergic to PCN or ampicillin, unable to take oral Tx?

A

Dosed 30-60 min before procedure

Cefazolin, ceftriaxone, clinda