Skin and Soft Tissue Infection Flashcards Preview

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Flashcards in Skin and Soft Tissue Infection Deck (28):

1. Define
2. Define Erysipelas
3. Define Cellulitis

1. Inflammation of the skin and subcutaneous tissues
2. upper dermis and superficial lymphatics
3. involves deeper dermis and subcutaneous fat


Cellulitis Presentation
1. Signs/Symptoms (4)
2. Predisposing factors (5)
3. Common Sites (3)

1. Varies: Erythema, swelling, tenderness, warmth, fevers/chills (systemic symptoms), lymphangitis, edema, induration (hardening); may have a sharp demarcation
2. Break in skin
skin conditions
3. Lower extremities
Places of skin breakdown


Common Bugs of Cellulitis
1. Gram +
2.Human bites (gram -)
3. Cat bites (gram -)
4. Dog Bites (gram -)

1. Gram +: Group A Strep, other hemolytic Strep, S. aureus (MRSA and MSSA)
2. Eikenella corrodens
3. Pasteurella multocida
4. Capnocytophaga canimorsus


Gram stain appearance of
1. Strep
2. Staph

1. Gram + cocci in chains
2. Gram + cocci in clusters


Differential Diagnosis for Cellulitis (3 main groups)

1. vascular disorders (thrombophlebitis, lymphedema)
2. Dermatologic disorders (contact dermatitis, drug rxns, insect stings/bites, urticaria)
3. Immunologic (gouty arthritis, Lupus, sarcoid)


1. Define Purulent Cellulitis
2. Define Non-purulent Cellulitis
3. What causes purulent?
4. What causes non-purulent?

1. cellulitis associated with purulent drainage (abscess) or exudate in abscence of drainable abscess
2. cellulitis with no purulent drainage, exudate, or abscess
3. Staph (MRSA)
4. Strep species and Staph (MSSA)


1. Where does purulent material drain from an abscess?
2. What does abscess feel like?

1. central area
2. fluctuant, moves


Purulent Cellulitis
1. Abscess management
2. No drainable abscess

1. incise and drain w/ gram stain and culture;
Need to give antibiotics
2. still need to cover CA-MRSA


Non-Purulent Cellulitis
1. What do you need to cover w/ Abx?
2. Specific Abx for MSSA and Strep
3. Specific Abx for CA-MRSA and Strep

1. cover Strep and staph species (MRSA coverage not necessary)
2. Beta-lactam (cephalexin, dicloxacillin)
3. Clinda, Linezolid, bactrim, or doxy + beta-lactam


How should joint infections be treated?

Aggressively; can have long lasting damage


Complications of Cellulitis (3)

1. Sepsis
2. Toxic Shock Syndrome (both Staph and Strep can cause)
3. Necrotizing Fasciitis


Risk Factors of Staph Toxic Shock Syndrome (9)

Menses, women, wound infections, mastitis, sinusitis, osteo, burns, lesions, arthritis


Staph Toxic Shock Syndrome Presentation
1. Systemic manifestations
2. Blood Cultures
3. Skin Manifestations (2)
4. Multi-organ involvement

1. fever, hypotension
2. usually negative
3. diffuse fine macular erythema; desquamation (often of palms/soles)
4. N/V; diarrhea; thrombocytopenia, delirium, transaminitis; mucosal hemorrhage/hyperemia


Staph TSS
1. What causes disease
2. Medical Management
3. Surgical Management

1. TSS toxin-1 (TSST-1) acting as a super Ag which activates a large number of T cells --> massive cytokine production and release
2. Supportive: fluids, vasopressor support; Abx
3. removal of any foreign body


Strep TSS
1. Risk Factors
2. Pathogenesis

1. Surgery, injuries, trauma
2. Group A Strep creates exotoxins that act as superantigens (pyrogenis exotoxin A and B: SPEA and SPEB)


Strep TSS Presentation
1. Systemic Manifestations
2. Skin
3. Other symptoms
4. Blood Cultures

1. fever or hypothermia, hypotension
2. swelling, erythema, skin sloughing; localized pain
3. altered mental state, renal dysfunction, DIC, ARDS
4. Positive Blood Culture in 50% of cases


Strep TSS Treatment
1. Medical
2. Surgical

1. supportive; Abx
2. removal of any foreign body


Necrotizing Fasciitis
1. Define
2. What bacteria are in Type I?
3. When does Type I occur
4. What bacteria are in Type II?

1. deep seated infection of subcutaneous tissue with destruction of fascia and fat
2. poly-microbial: aerobic/anaerobic; at least 1 or 2 staph/strep species
3. post surgery/ wound infection; Fournier's gangrene (perineal area)
4. GAS or MRSA; mono-microbial


Necrotizing Fasciitis- Clinical Presentations
1. Pain
2. How quickly does it progress?
3. Skin: initially
4. Skin: what does it progress to?
5. Systemic

1. out of proportion to how the skin looks; doesn't usually look that bad
2. rapidly evolving
3. initially: minimal, slight erythema
4. may become dark, bullae/vesicles, signs of necrosis/gangrene
5. Fever, hypotension


Necrotizing Fasciitis- Management
1. Surgery
2. Medical

1. early intervention is critical; all necrotic material must be removed
2. Empiric Abx: need to cover staph, strep, anaerobes, gram negatices (Vanco, zosyn, clindamycin)


1. Define
2. Common presentation
3. Which microorganisms cause it?
4. Diagnosis
5. Treatment

1. superficial bacterial infection that is contagious
2. kids, on the face, sites of mild trauma
3. Group A strep; S. aureus; can be polymicrobial
4. clinical
5. Topical and/or systemic antibiotics: should cover strep and staph


Bite wounds
1. Mono or poly microbial?
2. What is commonly present? (3)
3. What other species is common in cat bites?
4. What other species is common in dog bites?

1. poly-microbial
2. staph, strep, anaerobes
3. pasteurella species
4. capnocytophaga canimorsus (can cause rapid severe sepsis, esp in asplenic pts)


Soft Tissue infections due to animal bites: Management
1. Wound Care
2. When is Abx prophylaxis recommended?
3. Abx treatment (oral and alternatives)

1. Irrigation, evaluate for closure
2. Deep puncture wounds, severe or crush injuries, hand wounds or close to bone/joint, wounds requiring closure, immunocompromised
3. Oral: amoxicillin-clavulanate;
Alternatives: bactrim or doxycycline + flagyl or clindamycin


Vibrio Vulnificus
1. Gram Stain
2. What kind of food is it associated with?
3. Who is at greater risk for infection?
4. Pathogenesis

1. negative
2. shellfish
3. alcoholics, hematochromatosis
4. toxin and capsule give virulence; dependent on Fe


Vibrio Vulnificus
1. How does it present?

1. mild cellulitis; usually on hands/legs, can develop severe myositis/fasciitis


Pseudomonas causes skin infections in what situations (5)

1. after burns (common in burn sites, high mortality if it becomes bacteremic)
2. Trauma
3. skin grafts
4. Cellulitis in neutropenic pts
5. Folliculitis


How does Pseudomonas present on the skin when it is already in the blood?

initial small area of edema
painless nodules with ulceration, necrosis, or hemorrhage
almost abscess-like


Herpes Zoster (varicella)
1. What happens?
2. Presentation

1. reactivation of endogenous latent Varicella infection within the sensory ganglia
2. Painful, unilateral vesicular eruption (occurs after pain), dermatomal distribution, erythematous papules --> group into vesicles or bullae