Exam 3 - Skin/Soft Tissue Infections Flashcards
Most skin and soft tissue infections are caused by what bugs?
Beta hemolytic streptococci
or
Staphylococcus aureus
what does SSTI stand for
skin and soft tissue infections
what are the 3 main layers of skin
outer most –> inner most layers
epidermis – dermis – subcutaneous tissue
epidermis, dermis or subcutaneous tissue?
non-vascular layer composed of continuously dividing cells and the stratum corneum
epidermis
also the outermost layer
epidermis, dermis or subcutaneous tissue?
consists of connective tissue, blood vessels, lymphatics, sensory nerve endings, sweat and sebaceous glands, hair follicles and smooth muscle fibers
dermis
also layer directly beneath epidermis
epidermis, dermis or subcutaneous tissue?
layer of loose connective tissue primarily containing adipose cells
subcutaneous tissue
innermost layer
what is fascia and where is it located?
located beneath subcutaneous tissue layer – separates skin from underlying muscle
(deep fascia forms sheath that surrounds the muscle)
what is some important patient history info to gather about SSTIs?
immune status geographic locale travel history recent trauma or surgery lifestyle hobbies animal exposure/bites previous antimicrobial therapy
Impetigo symptoms?
superficial skin infecetions: maculopapular lesions with a dried, honey colored crust – usually on face around mouth
Impetigo:
Typically/most common form is Non_____ type
other is ______ type
Non-bullous type
or
Bullous
Impetigo
Non-Bullous type: usually what bug causes infection?
vs
Bullous type: usually what bug causes it?
Non-bullous – Group A strep
Bullous: MSSA
Risk factors for impetigo?
KIDS!! Hot/humid climates poor hygiene/day care settings (aka kids) crowing malnutrition diabetes
Topical treatment for impetigo
Mupirocin 2% or retapamulin 1% ointments BID x5
Oral options for Impetigo (systemic treatment)
Dicloxacillin Erythromycin (good if PCN allergy) Clindamycin (good if PCN allergy) Cephalexin Amox/Clav
Symptoms of Cellulitis?
Rapidly spreading erythema,
edema
tenderness
warmth in skin with a poorly defined border
common pathogenesis of cellulitis?
introduced to skin during trauma, lacerations, abrasions — FISSURED TOE WEBS FROM FUNGAL INFECTIONS OF FEET, cracks in dry skin
aka any cut in the skin……
What patients are at risk for cellulitis
anybody!! happens in healthy ppl because just any cut can cause this
(common in IV drug users, arterial/venous insufficiency, pts with diabetes or obesity, immunocompromised pts)
Erysipelas:
variant of ______ – caused by ____________
has ________ appearance; often involves the face
Only in _____ dermis and has clearly ________
variant of cellulitis – caused by beta hemolytic streptococci
has peau d’ orange appearance; often involves the face
Only in upper dermis and has clearly defined borders
most likely causative pathogens for cellulitis
S. Aureus (including MRSA) Streptococus Pyogenes (group A strep)
who is at hight risk for CA-MRSA with cellulitis infections
recent tattooed people inmates injection drug users Native American Populations Gat men Contact sport participants kids
Patients with skin infections due to CA-MRSA often have cellulits AND ________
abscess/pustules
why does CA-MRSA cause cellulitis AND abscesses/pustules?
CA-MRSA has genes for PVL (a virulence factor) been associated with TISSUE NECROSIS and ABSCESS FORMATION
CA-MRSA with cellulitis often susceptible to what drugs
doxycycline
Clindamycin
SMZ-TMP
Treat cellulitis like it has MRSA when?
in populations specified before like: recent tattooed people inmates injection drug users Native American Populations Gat men Contact sport participants kids
AND
if pt has an abscess!!
Cellulitis Treatment:
if no abscess or if gram stain/culture is inconclusive: empiric therapy should cover what bugs?
Group A strep AND staphylcoccus aureus
Cellulitis Treatment:
What drugs should be used for MILD infection/no MRSA suspected
dicloxacillin
cephalexin
Cellulitis Treatment:
What drugs should be used for MILD infection/MRSA suspected
SMZ-TMP
Clindamycin
Linezolid
Cellulitis Treatment:
What drugs should be used for MODERATE-SEVERE infection/no MRSA suspected
Nafcillin
Cefazolin
Cellulitis Treatment:
What drugs should be used for MODERATE-SEVERE infection/MRSA suspected
Vanc
Linezolid
Cellulitis Treatment:
What drugs should be used if patient has severe PCN allergy
Clindamycin
Vanc
Linezolid
Cellulitis Treatment:
how long to treat it
minimum 5 days!!
Cellulitis Treatment:
DIRECTED therapy towards strep. pyogenes — use what drug
PCN
Cellulitis Treatment:
DIRECTED therapy for MRSA
Vanc, Clindamycin, or SMZ-TMP
Cellulitis Treatment:
DIRECTED therapy for Gram - bacilli
3rd gen cephs
extended spectrum PCN (piperacillin
FQs
Cellulitis Treatment:
DIRECTEd therapy for Polymicrobial with anaerobes
beta lactamse inhibitor combo (pip tazo) OR 3rd gen ceph OR FQ w/ metronidazole OR Carbapenem alone....... wtffff
Necrotizing Fasciitis:
Symptoms?
INTENSE pain
wooden hard
systemic toxicity!!
Necrotizing Fasciitis:
Risk factors?
same as cellulitis!!
like any cut….
Necrotizing Fasciitis:
Common bugs?
Monomicrobial: group A strep (streptococcus pyogenes)
Polymicrobial: Gram - bugs AND anaerobes
Necrotizing Fasciitis:
Treatment – must have what two things
SURGICAL intervention (surgical debridment) and Broad AF spectrum drug coverage
Necrotizing Fasciitis:
Empiric Therapy?
Vanc + Pip/Tazo
meropenem
ceftriaxone/metronidazole
fluoroquinolone/metronidazole
Necrotizing Fasciitis:
Directed therapy for strep pyogenes
PCN + Clindamycin (suppress toxin production)
Necrotizing Fasciitis:
Directed therapy for clostridium
PCN + Clindamycin (suppress toxin production)
Necrotizing Fasciitis:
Directed therapy for Staph Aureus?
MSSA: Nafcillin/Cefazolin
MRSA: Vanc
what does DFI stand for
diabetic foot infection
why are diabetics at increased risk for DFIs??
bc neuropathy, angiopathy with ischemia, immune system defects, decreased wound healing
Not all diabetic ulcers/wounds are infected:
to be considered infected they have to have at least __#__ signs and symptoms of inflammtion
What are the signs/sypmtoms
at least 2
redness, warmth, swelling/induration tenderness or pain
what system is used to classify diabetic foot infections
PEDIS Grade
A PEDIS grade of _____ is considered mild infection seveirty
2
A PEDIS grade of _____ is considered moderate infection severity
3
A PEDIS grade of _____ is considered severe infection severity
4
what does SIRS stand for
Systemic inflammatory response signs
T or F: Abx alone are great for treating DFIs
false!!
need appropriate wound care (debridement)
Tight glycemic control
Optimizing blood flow too
Difference between PEDIS Grade 2 (mild) vs PEDIS Grade 3 (moderate)?
2: local infection – only skin/SQ tissue – erythema is b/w 0.5 - 1.9 cm around ulcer
3: local infection – deeper than skin and SQ tissue – erythema is > 2 cm around ulcer
BOTH DO NOT HAVE SIRS
what are examples of SIRS
Temperature > 38 C or < 36 C
HR > 90 bpm
RR > 20 breaths/min
WBC > 12,000 or < 4,000
What criteria makes a DFI and PEDIS Grade 4/Severe?
Local infection described above + at least 2 or more SIRS!!
If MILD DFI:
Covering what bacteria?
beta hemolytic streptococic
and
Staph aureus
If MODERATE DFI:
Covering what bacteria?
Same as mild (beta hemolytic streptococic
and Staph aureus)
+ consider ENTEROBACTERIACEAE
If SEVERE DFI:
Covering what bacteria?
Same as moderate (beta hemolytic streptococic
and Staph aureus and ENTEROBACTERIACEAE)
+ MRSA, Pseudomonas and Anaerobes
want Pseduomonas coverage for DFIs when?
if pt has soaked their foot in water!
also if pt is failing therapy w/out pseudomonal coverage or if pt has SEVERE DFI
Duration of Therapy for DFIs:
Mild infections?
1- 2 weeks
Duration of Therapy for DFIs:
Moderate infections?
1 - 3 weeks
Duration of Therapy for DFIs:
Severe infections?
2- 4 weeks
Duration of Therapy for DFIs:
if bone involvement?
4 - 6 weeks
Empiric Therapy for DFIs:
Mild Infection?
PO Cephalexin OR
PO dixcloaxillin OR
PO Augmentin
or PO Clindamycin or PO SMX/TMP
Empiric Therapy for DFIs:
Moderate infection?
IV cefazolin
(IV ceftriaxone alone if enterbacteriaceae suspected)
add PO metronidazole if anaerobes suspected
Empiric Therapy for DFIs:
Severe infection?
BROAD SPEC AS HELL:
VANC + Pip/Tazo or VANC + meropenem or VANC + Ceftazidime + metronidazole or VANC + Cefepime + metronidazole or VANC + FQ + metronidazole
what organisms are we trying to cover for empiric therapy of severe DFIs?
strep, staph (MSSA and MRSA), enterbacteriaceae, pseudomonas, and anaerobes….
Non-antibiotic options for treatment of DFIs?
appropriate wound care!! debridement/stay off it/bed rest
tight glycemic control
optimizing blood flow (smoking cessation/stents..)
