SSTI Flashcards

1
Q

PathophysiologyofSSTIs

A

Disruptionofnormalhostdefensesbyprocesses

suchas puncture,abrasion,diseases

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2
Q

Normalprotectingfactors of skins

A
Normalprotectingfactors
–Drysurface 
–AcidicpH(~5.6) 
–Fattyacids 
–Renewalofepidermis 
–Lowtemperature
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3
Q

Predisposingfactors to ssti

A
Predisposingfactors 
–Highbacterialinnocula 
–Excessivemoisture 
–Reducedbloodsupply 
–Presenceofbacterialnutrients 
–Poorhygiene 
–Sharingofpersonalitems
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4
Q

Classification of SSTIs

A

Presence/absenceofdischarge
–Purulentversusnon‐purulent

Severityorextent
–Mildversusmoderateversussevere
–Uncomplicatedversuscomplicated
–Superficialversusdeep

Microbiology
–Singlepathogen(primary)versuspolymicrobial(secondary)

Anatomicalsite
–Hairfolliclesversusepidermisversusdermis,etc.

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5
Q

Classification according to anatomical sites

- Epidermis

A

impetigo

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6
Q

Classification according to anatomical sites

- dermis

A

Erysipelas

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7
Q

Classification according to anatomical sites

- Hair follicules

A

Folliculitis
Furuncles
Carbuncles

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8
Q

Classification according to anatomical sites

- Subcutaneous fat

A

Cellulitis

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9
Q

Classification according to anatomical sites

- Fascia

A

Necrotizing fasciitis

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10
Q

Classification according to anatomical sites

- Muscle

A

Myositis

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11
Q

Skinandsofttissueinfections shouldgenerally be treatedwithantibiotics
—- some can be treated by draining

Antibiotics(systemicandtopical)areavailableby prescriptiononly
–Exception:topicalclindamycin≤1%(acneonly)

Pharmacistsplayanimportantrole
– Referpatientstoseekmedicalcareifindicated
– Counselonnon‐pharmacologic approaches
– Recommendappropriateantibioticregimens
– Monitor forsafetyandefficacyoftherapy

A

Skinandsofttissueinfections shouldgenerally be treatedwithantibiotics
—- some can be treated by draining

Antibiotics(systemicandtopical)areavailableby prescriptiononly
–Exception:topicalclindamycin≤1%(acneonly)

Pharmacistsplayanimportantrole
– Referpatientstoseekmedicalcareifindicated
– Counselonnon‐pharmacologic approaches
– Recommendappropriateantibioticregimens
– Monitor forsafetyandefficacyoftherapy

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12
Q

Exclusionsforself‐treatmentofwounds

A

–Woundscontainingforeignobjects
–Chronicnon‐healingwounds
–Deepwounds
–Involvementofface,mucousmembrane,orgenitalia
–Woundsduetoanimalorhumanbites
–Noimprovementorworseningafter5days
–Signsofinfection
(PayattentiontoclinicalpresentationofSSTIs)

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13
Q

what is Impetigo

A

UncomplicatedformofSSTIaffectingtheepidermisorup tothedermal‐epidermaljunction
Commoninchildren
Highlycontagious
Ecthymaisformofimpetigo –Ulcerative–> scarring Usuallymanagedoutpatient

1) non-bullous
2) bullous (due to bacterial toxin production).
May rupture –> erythematous erosion
3) Ecthyma - more severe form. tend to form scar even after infection is clear.

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14
Q

Impetigo causative organism and culture

A
  • S. aureus
  • B-hemolytic streptococci (eg streptococcus pyogenes)
  • Bullous form caused by toxin-producing strain of s. aureus

Cultures(optional)
– Maycultureifpusorexudate
– Reasonabletreatwithoutculture •EmpiricallycoverS.aureusANDβ‐hemolyticStreptococci

Hospital‐acquired(HA‐MRSA)
Community‐acquired(CA‐MRSA)
– Geneticallydifferentbackground
•Panton‐Valentineleucocidin(PVL)
•SCCmecIV
– Usuallysusceptibletooralnon‐beta‐lactams(e.g.clindamycin)

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15
Q

MRSA Risk factor

A
 Hemodialysis 
 Outpatientchemotherapy 
 Long‐termcarefacilitiesresidents 
 Athletes 
 Militaryrecruits 
 Menwhohavesexwithmen(MSM) 
 HistoryofMRSAinfectionorcolonization
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16
Q

Impetigo treatment

A

Topicaltherapy
– Impetigo–limitedlesions
– Mupirocin1applicationBDx5days

 Systemic(oral)therapy
– Ecthymaorimpetigo– numerouslesions

Streptococci only:
- PENICILLIN VK 250-500mg PO QDS

MSSA and Streptococci (empirical)

  • Cloxacillin 250-500mg PO QDS
  • Cephalexin 250-500mg PO QDS

MRSA & MSSA & streptococci

  • Erythromycin 250mg PO QDS
  • Clindamycin 300mg PO QDS

All for 7 days

17
Q

Purulent SSTI

A

 Cutaneousabscesses
– Puscollectioninthedermis(ordeeper)

 Furuncles(“boils”)
– Infectionsofthehairfollicles
– Extendthroughthedermis
– Formsasmallabscess

 Carbuncles
– Involvesfewadjacentfollicles

18
Q

Cutaneous abscess is what

A

purulent SSTI

  • fluctuant red nodules
  • Encircled by erythematous swelling
19
Q

Furuncle is ?

A

Inflammatory nodule
overlying pustule

(one follicule affected)

20
Q

Carbuncle is ?

A

larger and deeper type of furuncle

affect many adjacent hair follicule

21
Q

Causative organisms for purulent SSTI and culture

A

S. aureus

large skin abscesses may be polymicrobial

Cultures
– Culture of pus is recommended (if have pus)
– Reasonable to treat without cultures (coz predictable)

22
Q

purulent SSTI treatment

A

 Recommendedtreatmentisincisionanddrainage(I&D)
 Adjunctivesystemicantibiotics
– Unabletodraincompletely
– LackofresponsetoI & D
– Extremesofage
– Immunosuppressed
– Severe/extensivediseaseandsystemicillness
• SIRScriteria:
- temperature>38 Cor90beats/min,
- respiratoryrate>24breaths/min,
- WBC>12,000or

23
Q

systemicinflammatoryresponsesyndrome criteria

A

• SIRScriteria:

          - temperature>38 Cor90beats/min,
          - respiratoryrate>24breaths/min,
          - WBC>12,000or
24
Q

Adjunctivesystemicantibiotics for purulent SSTI

A

– Oral(PO)isadequateinmostcases
–Intravenous(IV)maybenecessarywithseverediseasesor systemicillness(MEET one or more SIRS criteria)

MSSA only

  • cloxacillin 250 - 500mg PO QDS
  • Cephalexin 250 - 500mg PO QDS
  • Cefazolin 1g IV q8hr

MRSA and MSSA
- Clindamycin 300mg PO QDS
600mg IV Q8h

  • Erythromycin 250mg PO QDS
    500mg IV Q6h

ALL 5-7days
10 days for recurrent infection

25
Q

Cellulitis

A

Acuteinflammationofepidermis,dermisandsometimes superficialfascia
Purulentornon‐purulent Bacteriacaninvadelymphatictissueandblood (___ERYSIPELAS__) – Affectsuptosuperficialdermis andlymphatictissues

  • spreading poorly demarcated area of erythema
  • may be complicated by skin peeling and bullae formation
26
Q

Erysipelas

A

cellulitis

  • bright red
  • raised border
  • sharply demarcated
27
Q

Causative organisms for cellulitis

A

S. aureus
B-hemolytic strepto (strepto. pyogenes)
- almost always the cause of erysipelas

other based on comorbidities and mode of injury
- immunosuppressed = + Streptococcuspneumoniae, Escherichiacoli,Serratiamarcescens

  • chronic liver / renal disease = + Vibriospp.,Escherichiacoli, Pseudomonasaeruginosa
  • Dog/cat bite = Pasteurella,Streptococcusspp., Staphylococcusspp.,oralanaerobes
28
Q

cellulitis cultures

A

– Notroutinelyrecommended
– PurulentinfectionsifI&D,shouldbecultured
– Immunosuppressed,dog/catbites,immersioninjuriesor
severesystemicpresentation (Fever/chill)
• Culturecutaneousaspirates,biopsies,swabs
• Bloodcultures

29
Q

cellulitis treatment

A
(\_\_\_ABX selection )and(_ROUTE_)dependon 
–Systemicsignsofinfection(e.g.fever) 
–Severityofillness 
      •SIRScriteria * 
–Patientcomorbidities 
–MRSAriskfactors 
–Purulentversusnon‐purulent 
–Patientallergies
30
Q

Non-purulent cellulitis tx

A

Mild (no SNS of infection)
- Organism = Strepto spp

  • Penicillin VK PO 250-500mg QDS
  • Cephalexin PO 250-500mg QDS
  • Cloxacillin PO 250-500mg QDS
  • Clindamycin PO 300mg QDS

Moderate - w >=1 SIRS

  • Strep + saureus
    - 1 SIRS =
  • Penicillin VK PO 250-500mg QDS
  • Cephalexin PO 250-500mg QDS
  • Cloxacillin PO 250-500mg QDS
  • Clindamycin PO 300mg QDS
    - >= 2 SIRS = 
  • IV cefazolin 1g q8h
  • IV ceftriaxone 1-2g Q24h
  • IV Penicilin G 2-4 MU q4-6h (strep only)
  • IV Clindamycin 600mg q8h

Severe - with > 2 SIRS + hypotension/rapid progression, immunosuppressed, comorbidities (eg chronic liver / renal disease)
- Strep + MSSA + - gram -ve or anaerobes

  • MSSA ONLY
  • IV cefazolin 1g q8hr
  • IV ceftriaxone 1-2g q24h
  • IV amox/clav 1.2g q8h
  • IV pip/tazo 3.375g q6h
  • MRSA
  • IV Vancomycin 15-20mg/kg q8-12h
    PLUS
    IV cefttriaxone 1-2g q24hr
    OR
    IV Pip/tazo 3.375g q6hr
    OR
    IV meropenam 1g q8h

ALL for 5 days

  • may extend if not significantly improved
  • immunosuppressed may need 7-14days
31
Q

Purulent cellulitis treatment

A

Mild - no SNS of infection
- Strep + s.aureus

MSSA

  • PO Cephalexin 250-500mg QDS
  • PO Cloxacillin 250-500mg QDS

MSSA + MRSA

  • PO TMP/SMX 960-1920 mg BD (T:S; 1:5)
  • PO Clindamycin 300mg QDS
  • PO Doxycycline 100mg BD
  • PO Linezolid 600mg BD

Moderate - w >=1 SIRS

  • Strep + saureus
    - 1 SIRS =

MSSA

  • PO Cephalexin 250-500mg QDS
  • PO Cloxacillin 250-500mg QDS

MSSA + MRSA

  • PO TMP/SMX 960-1920 mg BD (T:S; 1:5)
  • PO Clindamycin 300mg QDS
  • PO Doxycycline 100mg BD
  • PO Linezolid 600mg BD
    - >= 2 SIRS =  MSSA
  • IV Cloxacillin 1-2g q4-6h
  • IV cefazolin 1g q8h

MSSA + MRSA

  • IV Clindamycin 600mg q8h
  • IV vancomycin 15-20mg/kg q8-12hr
  • IV Linezolid 600mg BD
  • IV Daptomycin 4mg/kg q24h

Severe - with > 2 SIRS + hypotension/rapid progression, immunosuppressed, comorbidities (eg chronic liver / renal disease)
- Strep + MSSA + - gram -ve or anaerobes

MSSA

  • IV cefazolin 1g q8h
  • IV ceftriaxone 1-2g q24h
  • IV amox/clav 1.2g q8h
  • IV Pip/tazo 3.375g q6h
MRSA
- IV Vancomycin 15-20mg/kg q8-12h
PLUS 
- IV ceftriaxone 1-2g q24h
OR 
- IV Pip/tazo 3.375g q6h
OR 
- IV meropenam 1g q8h

ALL for 5 days

  • may extend if not significantly improved
  • immunosuppressed may need 7-14days
32
Q

monitoring for cellulitis tx

A
  • safety
    -efficacy
    • assess for clinical response in 48-72hr
    • improved fever, pain, swelling, erythema, warmth (?)
      YES
  • if initial IV Abx, change to PO
  • afebrile x 48h
  • ALL for 5 days
  • may extend if not significantly improved
  • immunosuppressed may need 7-14daysNO
  • consider resistant organisms and or alternative causes
33
Q

Cellulitis complication

A
Bacteremia 
Endocarditis 
Toxicshock 
Glomerulonephritis 
Lymphedema 
Osteomyelitis 
Necrotizingsoft-tissueinfections,e.g.necrotizingfasciitis