SSTI Flashcards

1
Q

Epidermis?

A

Impetigo

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2
Q

Dermis?

A

Ecthyma

Erysipelas

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3
Q

Hair follicles?

A

Furuncles

Carbuncles

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4
Q

Subcutaneous fat?

A

Cellulitis

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5
Q

Pathogen causing impetigo & ecthyma?

A

• Staphylococcus aureus
• β-hemolytic Streptococci
(e.g. Streptococcus pyogenes)
Bullous form caused by toxin-producing strains of S. aureus

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6
Q

Need to culture for impetigo & ecthyma?

A

Optional; may culture if pus

Can tx w/o culture; empirically cover the 2 MO

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7
Q

Tx for impetigo?

A
Topical antibiotic (most cases)
Mupirocin BD x 5 days 
Oral antibiotic (severe cases)
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8
Q

Tx for ecthyma?

A

Oral antibiotic (all cases) x7d
Empiric (no allergies) Cephalexin
Cloxacillin

Empiric (penicillin allergic) Clindamycin

Culture-directed(S.pyogenes) Penicillin VK

Culture-directed (MSSA) Cephalexin
Cloxacillin

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9
Q

Purulent SSTIs includes?

A

Furuncles, carbuncles, cutaneous abscesses

Remember all are purulent

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10
Q

Risk factors of purulent SSTIs?

A
  • Close physical contact
  • Crowded living quarters (e.g. dormitories, military camps, prisons)
  • Sharing personal items
  • Poor personal hygiene
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11
Q

Culture for purulent SSTIs?

A

May culture pus

Usually tx w/o culture

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12
Q

Tx for purulent SSTIs?

A

Incision & drainage (I&D)

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13
Q

Criteria for adjunctive systemic antibx for purulent SSTIs?

A

Adjunctive antibx only:
• Unable to drain completely
• Lack of response to I&D
• Extensive disease involving several sites
• Extremes of age
• Immunosuppressed (e.g. chemotherapy, transplant)
• Signs of systemic illness (SIRS crit)

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14
Q

Antibx for adjunctive tx of purulent SSTIs?

A

MSSA
Cloxacillin
Cephelaxin
Cefazolin

MRSA
Clindaymycin
Co-trimoxazole
Doxycycline

Outpatient x 5-7 days
Inpatient x 7-14 days

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15
Q

Erysipelas discharge?

A

Non-purulent

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16
Q

Mild erysipelas & non-purulent cellulitis criteria & microb?

A

No signs of systemic infection (no SIRS)

Streptococcus spp

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17
Q

Culture for erysipelas & cellulitis?

A
Not routinely recommended 
Consider if:
•	Purulent infections after I&D 
•	Immunosuppressed 
•	SIRS criteria
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18
Q

Tx for mild erysipelas & non-purulent cellulitis

A
PO antibiotics
•	Penicillin VK
•	Cloxacillin 
•	Cephalexin 
•	Clindamycin
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19
Q

Moderate erysipelas & non-purulent cellulitis tx?

A

Streptococcus spp
± S. aureus

≥ 1 SIRS criteria
Treat like mild with PO antibiotics
•	Penicillin VK
•	Cloxacillin 
•	Cephalexin 
•	Clindamycin
≥ 2 SIRS criteria
IV antibiotics 
•	Cefazolin
•	Penicillin G
•	Clindamycin
20
Q

Severe erysipelas & non-purulent cellulitis criteria & microb?

A
> 2 SIRS criteria +
hypotension , rapid
progression,
immunosuppressed,
comorbidities
Streptococcus spp 
S. aureus 
gram-negatives
(include P. aeruginosa)
21
Q

Severe erysipelas & non-purulent cellulitis tx?

A
IV antibiotics 
•	Piperacillin/tazobactam 
•	Cefepime 
•	Meropenem
If MRSA risk factor(s) add IV:
-	Vancomycin 
-	Daptomycin 
-	Linezolid
22
Q

Mild purulent cellulitis criteria & microb?

A

No signs of systemic infection (no SIRS)
Streptococcus spp
± S. aureus

23
Q

Mild purulent cellulitis tx?

A
PO antibiotics 
•	Cephalexin 
•	Cloxacillin 
•	Clindamycin
If MRSA risk factor(s) use PO:
•	Co-trimoxazole 
•	Clindamycin 
•	Doxycycline
24
Q

Moderate purulent cellulitis criteria & microb & Tx?

A

Streptococcus spp
± S. aureus

≥ 1 SIRS criteria
Treat like mild with PO antibiotics

≥ 2 SIRS criteria
IV antibiotics
•	Cloxacillin 
•	Cefazolin 
•	Clindamycin 
If MRSA risk factor(s) add IV:
Vancomycin 
Daptomycin 
Linezolid
25
Q

Severe purulent cellulitis criteria & microb?

A
> 2 SIRS criteria +
hypotension , rapid
progression,
immunosuppressed,
comorbidities
Streptococcus spp 
S. aureus 
gram-negatives
(include P. aeruginosa)
26
Q

Severe purulent cellulitis tx?

A
IV antibiotics 
•	Piperacillin/tazobactam 
•	Cefepime 
•	Meropenem
If MRSA risk factor(s) add IV:
-	Vancomycin 
-	Daptomycin 
-	Linezolid
27
Q

Cellulitis from bite wound microb?

A
Streptococcus spp 
S. aureus 
Pasteurella multicide (animal)
Eikenalla corrodens (human) 
Oral anaerobes (e.g. Prevotella spp., Peptostreptococcus spp.)
28
Q

Cellulitis from bite wound tx?

A

IV/PO antibiotics depends on severity
• Amoxicillin/clavulanate
• Ceftriaxone/cefuroxime + clindamycin/ metronidazole
• Ciprofloxacin/levofloxacin + clindamycin/ metronidazole

29
Q

Tx algorithm for cellulitis/ erysipelas

A

assess response in 48-72h (2-3d) if improve switch from initial IV to PO for at least 5d; immunosuppressed 7-14d

30
Q

Complicatins of cellulitis & erysipelas

A
  • Bacteriemia
  • Endocarditis
  • Toxic shock
  • Glomerulonephritis
  • Lymphedema
  • Osteomyelitis
  • Necrotizing soft-tissue infections e.g. necrotizing fasciitis
31
Q

MRSA risk factors?

A
  • Immunosuppression
  • Critically ill e.g. hypotension caused by infection, in ICU
  • Failed antibx w/o MRSA coverage
32
Q

Definition of infection for DFI & pressure ulcers?

A
– Purulent discharge; 
or
– ≥ 2 signs or symptoms of inflammation:
• Erythema
• Warmth
• Tenderness
• Pain
• Induration
33
Q

DFI?

A

Soft tissue or bone infections below the malleolus due to:
• Skin ulceration (peripheral neuropathy)
• Wound (trauma)

34
Q

Pressure ulcers?

A
Bed sores 
Synergistic interaction between 4 factors: 
– Moisture
– Pressure (amount and duration)
– Shearing force
– Friction
35
Q

Cultures for both DFI & pressure ulcers?

A

MILD: optional
MODERATE – SEVERE:
Deep tissue cultures (after cleansing, b4 antibx) ** avoid skin swabs

36
Q

Mild DFI & PU microb & criteria?

A

Infection of skin and SC tissue (erythema: ≤ 2 cm around ulcer)
No signs of systemic
infection (no SIRS)

Streptococcus spp
S. aureus

37
Q

Mild DFI & PU tx?

A
PO antibiotics 1-2weeks
•	Cephalexin 
•	Cloxacillin 
•	Clindamycin
If MRSA risk factor(s) use PO:
-	Co-trimoxazole 
-	Clindamycin 
-	Doxycycline
38
Q

Moderate DFI & PU microb & criteria?

A
  1. Infection of deeper tissue
    (e.g. bone, joints)
  2. Erythema: > 2 cm
  3. No signs of systemic
    infection (no SIRS)
    Streptococcus spp
    S. aureus
    Gram-negatives
    (±P. aeruginosa)
    Anaerobes
39
Q

Moderate DFI & PU tx?

A
Initial IV antibiotics 1-3weeks
•Amoxicillin/clavulanate
•	Ceftriaxone*
•	Ertapenem
If MRSA risk factor(s) add IV:
-	Vancomycin 
-	Daptomycin 
-	Linezolid
*If no anaerobic coverage, add IV:
	Metronidazole
	Clindamycin 
May step-down to PO antibiotic(s) after patient improves
40
Q

Severe DFI & PU microb & criteria?

A
Sign(s) of systemic infection
(with SIRS)
Streptococcus spp 
S. aureus 
Gram-negatives 
(+P. aeruginosa) 
Anaerobes
41
Q

Severe DFI & PU tx?

A
Initial IV antibiotics 2-4weeks
•	Piperacillin/tazobactam
•	Cefepime*
•	Meropenem
If MRSA risk factor(s) add IV:
-	Vancomycin 
-	Daptomycin 
-	Linezolid
*If no anaerobic coverage, add IV:
	Metronidazole
	Clindamycin 
May step-down to PO antibiotic(s) after patient improves
42
Q

Complication of DFI

A

Complications of DFI
• Hospitalization
• Osteomyelitis  amputation

43
Q

Pseudomonal risk factors (patient-specific factors)

A

Empirically cover Pseudomonas aeruginosa when:
o Severe infection
o Failure of antibiotics not active against Pseudomonas aeruginosa

44
Q

Adjunctive measures of DFI

A
1.	Wound care
•	Debridement
•	“Off-loading”
•	Apply dressings that promote a healing environment and control excess exudation
2.	Foot care 
•	Daily inspection
•	Prevent wounds and ulcers
45
Q

Risk factors of pressure ulcers?

A
  1. Reduced mobility – E.g. spinal cord injuries, paraplegic
  2. Debilitated by severe chronic diseases – E.g. multiple sclerosis, stroke, cancer
  3. Reduced consciousness
  4. Sensory and autonomic impairment – Incontinence (increase moisture in certain parts of skin)
  5. Extremes of age
  6. Malnutrition
46
Q

Adjunctive measures of pressure ulcers?

A
  1. Debridement of infected or necrotic tissue
  2. Local wound care
    • Normal saline preferred
    • Avoid harsh chemicals
  3. Relief of pressure
    • Turn or reposition every 2 hours
    • Also important for prevention
47
Q

Risk factors/ pathophysiology of DFI?

A

1.Neurpathy
decrease pain sensation, muscle imbalance, dry
2. Vasculopathy
atherosclerosis, PVD, hyperglycemia, hyperlipidemia
3. Immunopathy
impaired immune response, more susceptible to infections, hyperglycemia