Skin/Soft tissue/Bone Infections Flashcards
Skin and soft tissue infections are most commonly seen where?
Outpatient and inpatient
Skin and soft tissue infections can affect a single or all layers of what?
Fascia, skin, or muscle
(T/F) - Skin surface is conducive to bacterial growth - not resistant to infection
FALSE - it is NOT conducive to bacterial growth - resistant to infection
What are reasons that skin is resistant to infection?
- Extremely dry surface
- Continual renewal of skin cells
- Sebaceous secretions inhibit the growth of many bacteria and fungi
What are risk factors for skin infection?
- High concentrations of bacteria (> 10^5)
- Inadequate blood supply
- Damage to the stratum corneum allowing for bacterial entry
- Availability of nutrients
- Excessive moisture of the skin
What is normal flora that is common in exposed skins (face, neck)?
Staph. epidermidis
What is the normal flora that is common in moisture areas (axilla, groins)?
Acinetobacter spp.
What are other predominant bacterial organisms of normal skin other than staph. epidermidis and acinetobacter spp.?
- Corynebacterium spp.
- Propionibacterium spp.
- Micrococcus spp.
What are predominant fungal organisms involved in normal skin?
- Malassezia spp.
- Candida spp.
What are the classic signs and symptoms of a patient experiencing skin or soft tissue infection?
- Heat/localized fever
- Erythema/redness
- Inflammation/swelling
- Pain
Define primary infections of skin/soft tissue infections
Usually involve areas of previously healthy skin and typically caused by one pathogen
Define secondary infections of skin/soft tissue infections
Usually occur in areas of previously damaged skin and often polymicrobic
What are some primary skin/soft tissue infections (SSTIs)?
- Impetigo
- Erysipelas
- Purulent SSTIs
- Cellulitis
- Necrotizing fasciitis
Define impetigo
Superficial infection of stratum corneum
Impetigo is usually involved in which population(s)?
- Children
- Poor hygiene
What organisms cause impetigo?
- Staph. aureus (including MRSA)
- Group A streptococci
How is impetigo usually clinically presented?
- Purulent, localized vesicles/lesions
- Mild pain, pruritus
- Common in exposed areas
What nonpharmacological therapy can be done with impetigo?
Wash affected area with soap and water
What topical treatment can be used for impetigo, localized lesions? For how long?
- Mupirocin
- Retapamulin
Both for 5 days
What oral treatment can be used for impetigo, extensive/nonresponsive? For how long?
- Dicloxacillin
- Cephalexin
- Amoxicillin/clavulanate
Both for 7 days
Define erysipelas
Cellulitis involving the more superficial layers of the skin and cutaneous lymphatics
Erysipelas is usually involved in which population(s)?
- Very young
- Very old
What organisms cause erysipelas?
Group A streptococci
How is erysipelas usually clinically presented?
- Raised, erythematous with clear line demarcation
- Orange peel appearance
- Often with systemic symptoms (fever, malaise)
- Intense burning
- Common in lower extremeties
What are the treatment options for erysipelas? For how long?
- PCN G (IV, PO, IM)
- Amoxicillin
Both for 7-10 days
There are 3 types of purulent SSTIs, what are they?
- Furuncles
- Carbuncles
- Cutaneous abscess
Define furuncle’s
Infection of hair follicles that usually extend through the dermis into the SQ tissue resulting in small abscess
Define carbuncles
Inflammatory nodules that extends through multiple adjacent follicles
Which population has a chance of gaining purulent SSTIs?
Those who have irritated/injured hair follicles/skin
What organisms cause purulent SSTIs?
Staph. aureus (including MRSA)
(T/F) - Carbuncles usually start as a firm, tender, red nodule, that become painful and fluctuant
FALSE - This is describing farbuncles
(T/F) - Carbuncles are inflamed, drain nodule involving a hair follicle
FALSE - This is describing farbuncles
(T/F) - Furuncle’s lesion often drain spontaneously
TRUE
(T/F) - Carbuncles lesions caused by CA-MRSA often have a characteristic of a ‘spider bite’
FALSE - This is describing furuncle’s
(T/F) - Carbuncle’s form a broad, swollen, erythematous, deep, and painful follicular masses
TRUE
(T/F) - Furuncle’s commonly develop at the back of the neck and are likely to occur in diabetic patients
FALSE - This is describing carbuncles
What is highly recommended for all carbuncles, large furuncles, and abscesses?
- Incision and drainage
- Culture and sensitive testing
How is a mild (localized but no signs of systemic infections) purulent SSTIs treated?
No need for antibiotics
How is a moderate (signs of systemic infection) purulent SSTI treated empirically? For how long?
- Doxycycline
- TMP/SMX
For both 5-10 days PO
How is a moderate (signs of systemic infection) MRSA purulent SSTI treated? For how long?
- TMP/SMX
For 5-10 days PO
How is a moderate (signs of systemic infection) MSSA purulent SSTI treated? For how long?
- Doxycycline
- Cephalexin
For 5-10 days PO
When should PO meds be switched to IV meds for purulent SSTIs?
- Failed incision and drainage plus PO antibiotics OR
- Systemic inflammatory response syndrome (SIRS) is present
What are the SIRS symptoms?
- Fever
- Hypotension
- Tachypnea
- Tachycardia
- High WBC count
How is a severe purulent SSTI treated empirically? For how long?
Treat as if it were MRSA infection - Vancomycin - Daptomycin - Linezolid - Ceftaroline - Dalbavancin - Ortiavancin - Telavancin For all of them 5-10 days IV
How is severe MRSA purulent SSTI treated? For how long?
Same as severe purulent SSTI treated empirically
How is severe MSSA purulent SSTI treated? For how long?
- Nafcillin
- Oxacillin
- Clindamycin
Define cellulitis
Involves the deeper dermis and SQ fat
Who is at risk of gaining CA-MRSA of cellulitis?
- Smoker
- Diabetics
- Recurrent infections
- IVDU
- Skin contact
- Sharing personal contaminated items
- Lack of cleanliness
- Crowding
- IVDU
What are the most common organisms that cause cellulitis?
- Group A streptococci
- Staph. aureus
