Exam 3: Skin and Soft Tissue Infections/ Diabetic Foot Infections Flashcards by TheOneandOnly Ash

What are the risk factors for developing skin and soft tissue infections?

*History of SSTI
Peripheral Artery Disease
Chronic Kidney Disease
Diabetes Mellitus
IV Drug Use

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What are the 3 types of skin and soft tissue infections?

Non-purulent
Purulent
Necrotizing fasciitis

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What are the 2 types of non-purulent skin and soft tissue infections?

Cellulitis

Erysipelas

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What is the defining characteristic of non-purulent skin and soft tissue infections?

NO PUS

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Why do we not obtain skin cultures with non-purulent infections?

The culture would be contaminated with skin bacteria

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What are the symptoms of non-purulent SSTIs?

Tender, Erythema, Swelling, Warm to touch

Orange peel-like skin

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What testing should we do for non-purulent SSTI’s?

*Skin and blood cultures are not routinely recommended

Blood cultures recommended if: immunocompromised, animal bites, severe infection

CT/MRI imaging to rule out necrotizing fasciitis or abscess

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In what 3 circumstances would we take blood cultures for a patient with a non-purulent SSTI?

Immunocompromised
Severe infection
Animal bites

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What are the 3 classifications used for both non-purulent and purulent SSTIs?

Mild
Moderate
Severe

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What is a mild non-purulent or purulent SSTI?

No systemic signs of infection

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What is a moderate non-purulent or purulent SSTI?

Systemic signs of infection

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What is a severe non-purulent or purulent SSTI?

Meets at least 2 SIRS criteria

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What are the 4 SIRS criteria?

Temp <36C or >38C

HR > 90bpm

RR> 24bpm

WBC <4k or >12k

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What is the SIRS criteria regarding temperature?

<36C or >38C

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What is the SIRS criteria regarding HR?

> 90bpm

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What is the SIRS criteria regarding respiratory rate?

> 24bpm

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What is the SIRS criteria regarding WBCs?

<4k or >12k

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What is the most common pathogenic organism in non-purulent SSTIs?

Streptococcus species

-S. pyogenes
-S. agalactiae
-S. equismilis
-S. anginosus

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Under what circumstances would we want to add MRSA coverage in a non-purulent SSTI?

Always add MRSA coverage if patient meets SIRS criteria

Otherwise:
-Penetrating trauma
-Evidence of MRSA elsewhere
-Nasal colonization with MRSA
-IV drug user
-SIRS/Severe infection
-Failed a non-MRSA antibiotic regimen

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How long is the typical non-purulent SSTI therapy duration?

5 days

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What is the treatment for a non-purulent MILD SSTI?

Oral Antibiotics (pick 1)

-Penicillin VK
-Dicloxacillin
-Cephalosporin
-Clindamycin

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What is the treatment for a non-purulent moderate SSTI?

IV antibiotics (systemic, pick 1)

-Penicillin
-Ceftriaxone
-Cefazolin
-Clindamycin

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What is the treatment for a non-purulent severe SSTI?

Emergency Surgical Inspection/Debridement

Empiric Antibiotics:
-Vancomycin + Piperacillin/Tazobactam

Then send to lab and narrow based on culture

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What are the 3 types of purulent SSTIs?

Abscesses
Furuncles
Carbuncles

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What is the defining characteristic of a purulent SSTI?

Pus is present

What is an abscess?

A collection of pus in the dermis and deeper skin tissues

What is a furuncle?

(boil) Small abscess that forms at a hair follicle

What is a carbuncle?

Infection involving several adjacent hair follicles

What is the presentation of a purulent SSTI?

Tender, Red nodules, Erythema, Warm to touch **Systemic signs of infection (less common with furuncles)

What testing should be done to diagnose purulent SSTIs?

Cultures *recommended for ALL abscesses, carbuncles, and patients with systemic infection regardless of severity CT/MRI imaging to confirm presence of abscess

What is the most common causative pathogen of Purulent SSTIs?

*MRSA* -also MSSA and streptococcus species

How long is the typical duration of Purulent SSTI treatment?

5 days

What is the one treatment that all purulent SSTI patients should receive?

Incision and Drainage!

What is the treatment for mild purulent SSTIs?

Incision and drainage -no abx therapy needed

What is the treatment for moderate purulent SSTIs?

Incision and Drainage Culture + Stain Empiric (pick 1): -TMP/SMX -Doxycycline Targeted: MRSA (both): -TMP/SMX -Doxycycline MSSA (pick 1): -Dicloxacillin -Cephalexin

What is the treatment for severe purulent SSTIs?

Incision and Drainage Culture and Stain Empiric (pick 1): -Vancomycin -Daptomycin -Linezolid Targeted: MRSA: *same as empiric MSSA (pick 1): -Nafcillin -Cefazolin -Clindamycin

What are the characteristics of necrotizing fasciitis?

"Severe non-purulent infection" *Medical emergency* High morbidity + mortality

What is the typical presentation of necrotizing fasciitis?

-Profound systemic toxicity (fever, lethargy, disorientation) -Change in skin color to maroon/purple/black -Crepitus (cracking/popping sound) -Edema -Severe pain

What tests should be run to diagnose necrotizing fasciitis?

Blood cultures recommended Wound cultures (obtained from surgery) CT/MRI imaging to confirm necrotizing fasciitis or presence of abscess (looking for presence of gas)

What is the #1 cause of necrotizing fasciitis?

Streptococcus species (especially pyrogenes) -causes toxin production

What is the treatment for necrotizing fasciitis?

Emergency surgical inspection/debridement Empiric antibiotics: -Vancomycin + Piperacillin/Tazobactam Targeted antibiotics: S. Pyogenes: Penicillin + Clindamycin Polymicrobial: Vancomycin + Piperacillin/Tazobactam

What is the typical duration of necrotizing fasciitis treatment?

-Until further debridement is no longer necessary -Patient has clinically improved -Fever has been absent 48-72 hours

Why is clindamycin used in necrotizing fasciitis treatment?

-Inhibits streptococcal toxin production -Inoculum effect: clears a pathway for penicillins to work in the high bacterial load

What is Impetigo?

A highly contagious superficial skin infection caused by skin abrasions

Where is impetigo most common?

Children Hot/Humid weather

What is the typical presentation of impetigo?

Small, painless, fluid filled vesicles that can lead to thick golden crusts -Systemic signs of infection are rare

What testing can be done to diagnose impetigo?

Cultures from pus/exudates are recommended but not required

How do we treat Impetigo with few lesions?

Topical abx for 5 days -Mupirocin

How do we treat Impetigo with many lesions/an outbreak in a household?

*Oral for 7 days*: Dicloxacillin or Cephalexin If streptococcus only: -Penicillin If allergies/MRSA: -Doxycycline -Clindamycin -TMP/SMX

What testing should be done on animal bites?

Blood cultures are recommended

What is considered an established infection for animal bites?

x 7-14 days

What is considered a Preemptive infection for animal bites?

x 3-5 days

For animal bites, who should receive preemptive therapy?

Immunocompromised/ Asplenia Moderate to severe bites Bites on face/hand Bites that penetrate joints

What is the drug of choice for animal bites?

Amoxicillin/ Clavulanate

Who should receive a Tdap vaccine with animal bites?

Anyone who is due for one

What tests should we run on diabetic foot infections?

Wound cultures are not recommended for mild infection Bone cultures are normally obtained after debridement Blood cultures can be considered

What are the most common pathogens in a diabetic foot infection?

S. aureus Streptococci species

What are the risk factors for MRSA with diabetic foot infections?

Previous MRSA infection in the last year Local MRSA prevalence >30-50% Recent hospitalization Failed non-MRSA antibiotics

What are the risk factors for Pseudomonas with diabetic foot infections?

History of pseudomonas infection Soaking feet in water Warm climate Severe infection Failed non-pseudomonal antibiotics

What are the 3 parts of diabetic foot infection management?

Surgical intervention Glycemic control Antibiotics

What are the 1st line therapy options for a Mild diabetic foot infection?

Dicloxacillin Cephalexin Clindamycin

If a patient with a mild diabetic foot infection has used antibiotics recently, what do we switch their treatment to?

Amoxicillin/Clavulanate Levofloxacin Moxifloxacin

If a patient with a mild diabetic foot infection has MRSA risk factors what do we switch their treatment to?

Sulfamethoxazole/Trimethoprim Doxycycline

How long do we treat a mild diabetic foot infection?

1-2 weeks

What are the first-line options for a moderate diabetic foot infection?

Moxifloxacin Amoxicillin/Clavulanate Cipro/Levofloxacin + Clindamycin/Metronidazole

If a patient with a moderate diabetic foot infection has pseudomonal risk factors what do we do for treatment?

Switch to: Cipro/Levofloxacin + Clindamycin/Metronidazole

If a patient with a moderate diabetic foot infection has MRSA risk factors what do we do for treatment?

Doxycycline Linezolid Vancomycin Sulfamethoxazole/Trimethoprim

How long do we treat a moderate diabetic foot infection?

2-3 weeks

What are the first line agents to treat a severe diabetic foot infection?

Piperacillin/Tazobactam Carbapenem Cefepime + Clindamycin/Metronidazole

What treatment options do we have to treat a severe diabetic foot infection with MRSA risk factors?

Vancomycin Linezolid Daptomycin

How long do we treat a severe diabetic foot infection?

2-3 weeks (same as moderate)

Exam 3: Skin and Soft Tissue Infections/ Diabetic Foot Infections Flashcards

(71 cards)