SKIn and Soft Tissue- Part 1 Flashcards by Jimleo Badilla

Normal Flora of the Superficial Skin

Bacillus (except anthraces, cereus)
Lactobacillus
Micrococcus
CONS (except Lugdunensis)
Corynebacterium sap-diphtheroids
Proprionibacterium acnes
Viridans streptococcus group

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single or small area of skin with abnormal growth or appearance

Lesions

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flat discolouration of skin

Macule

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elevated solid lesion with distinct border

Papule

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a papule > 0.5 cm, may affect subcutaneous tissue

Nodule

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raised lesion (varies in size) with fluid & pus

Pustule

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blister with clear fluid

vesicle

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type of vesicle- larger, fluid trapped sacs

Bullae

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excess dead skin cells, causes thickening and crusting

Scales

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crater-like sore on skin

Ulcers

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a widespread eruption of lesions

rashes

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a rash on skin surface (example: dermatitis)

Exanthem

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rash on a mucus membrane inside the body (example: in the throat)

Enanthem

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a painful collection of pus, bacteria and dead tissue in an enclosed tissue space

abscess

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inflammation of the surface of skin with rash; can be caused by genetics, an overactive immune system, allergies, or irritating substances

Dermatitis

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a type of dermatitis characterized by skin inflammation due to moisture (sweat) collecting in hot areas of folds of skin (armpit, groin under breasts) + friction;
- breakdown of skin can result in secondary infection by bacteria or fungus
-caused mostly by Candida spp, Dermatophytes, Malasezzia furfur, S aureus and coliforms

Intertrigo

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an infection of the surface of the skin caused by NSF, Corynebacterium minutissimum
-results in red or brown patches in folds of skin
-can also be caused by Candida spp., Dermatophytes and Malassezia furfur
-Dermatophytes cause circular scaly patch of erythema with raised border- called Tinea
-Malasezzia causes white patches in those with darker skin and brown patches in those with pale skin

Erythrasma

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group of inflammatory skin disorders that is characterized by the production of pus
-types:
Impetigo
Folliculitis
Furuncle (boil)
Carbuncle
Erysipelas
Cellulitis

Pyodermas

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occurs mostly in children 2-5 years
-caused most commonly by S. aureus, followed by GAS
-or by GBS in newborns
-affects skin around the nose and mouth or arms and legs
-start as small vesicles that become rupturing pustules
-have a thick yellow discharge that form golden crusts
-contagious
-Bullous form caused by S aureus that produce an exfoliative toxin

Impetigo

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papular or pustular inflammation of hair follicles
caused mostly by S aureus and MRSA

Folliculitis

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painful, film or fluctuant abscess originating from a hair follicle
-also called a boil
-caused mostly by S aureus and MRSA

Furuncle

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a network of furuncles connected by sinus tracts
-are more serious because go deeper into tissue and can lead to bacteremia
-often have to be surgically drained

Carbuncle

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acute spreading inflammation of the superficial skin and subcutaneous fat tissues
-occurs mostly on legs and face
-Happens when S aureus, GAS, other BHS enter the skin from mild trauma or a wound, burn, or surgical incisions
-can become more serious if organism gets into the lymphatics and blood stream
-SKIN IS HOT, EVENLY SWOLLEN AND ORANGEY/ PINKY RED
-THE LINE OF DEMARKATION BETWEEN INVOLVED AND UNINVOLVED SKIN IS NOT DISTINCT

Cellulitis

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a superficial type of cellulite that also affects mostly the legs and face
-it is also usually caused by S aureus and GAS
-the organism can spread into the lymphatic system
-SHINY, FIRM DEEPLY RED PLAQUES RAISED ABOVE THE SURROUNDING SKIN
-CLEAR DISTINCT MARGINS BETWEEN INVOLVED AND UNINVOLVED TISSUE

Erysipelas

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Common pathogens from a dog or cat bite

Pasteurella, Staph, strep + other oral flora including anaerobes

Common pathogens from a dog or cat bite

Pasteurella, Staph, strep + other oral flora including anaerobes

Common pathogens from human bites

Streptococcus anginosi S aureus Eikenella Fusobacterium Prevotella

common in diabetics because of their compromised vascular circulation -infections seen as cellulitis, or acute/chronic ulceration that may progress to osteomyelitis and gangrene -infections often due to a mixture of bacteria like Staph, strep, enterobacterales, pseudomonas, and anaerobes -most infections require debridement if becomes severe enough to need amputation

diabetic foot infections

injury to skin due to long period of constant pressure -decreased blood flow leads to tissue damage and tissue death -common in infirm people who can't move- elderly -starts as a pressure sore then becomes a decubitus ulcer (bed sore)

pressure sore/decubitus ulcer (bed sore)

1. Painful, hot, unbroken discoloured skin 2. Blister or shallow ulcer leaking fluid or pus

Pressure sore

3. Deep ulcer affecting fat layer 4. Very deep ulcer where you see muscle or bone

Decubitus ulcer

infections that cause tissue necrosis -initially affects skin, fascia and subcutaneous fat- and progresses to muscle tissue -rapid, life threatening- often requires surgical debridement or amputation

Necrotizing skin and soft tissue infections

due to a polymicrobial infection- may include GAS, S aureus, Enterobacterales and anaerobes

Type I

due most commonly to GAS alone or 2nd mosts commonly by S aureus alone or very rarely, by both together

Type II

due to a marine bacteria V vulnificans

Type III

due to Clostridium spp

Gas gangrene

skin infection due to a SA that produces exfoliative or epidermolytic toxin -causes blistering and peeling of skin can be localized or spread to 90% of body -affects children < 6 yrs old (primarily in newborns) -can happen in immunocompromised adults

S aureus Scalded Skin syndrome

a rare, potentially fatal multisystem disease -begins with fever, sun burn like rash, peeling skin progresses quickly to hypotension, organ failure, shock and death -one cause is production of TSST-1 exotoxin

Toxic Shock Syndrome

a type of TSS associated with high absorbency tampon use in women who have this organism as normal flora in their vagina or on hands

Menstruating associated

type of TSS associated with any Staph infection especially post surgical ones

Non menstruating associated

__ % of CA MRSA infections are localize to skin and soft tissue OFTEN BEGINS AS A PAINFUL SKIN BOIL (LOOKS LIKE A ______ ________)

75 SPIDER BITE

very rare type of S aureus skin and soft tissue infection -when it happens it is mostly in those who are immunocompromised -increasingly due to community acquired MRSA -rapid and serious infection that affects skin, fascia, subcutaneous and muscle tissue -a number of exotoxins cause decreased coagulation and fluid leakage in tissue results in swelling and bull formation

S aureus Type II Necrotizing infection

caused by an infection with a GAS that produces a pyrogenic exotoxin -toxin damages plasma membranes of capillaries -is seen as a diffuse red rash on the upper chest that spreads to the trunk and extremities- followed by desquamation of skin -may also have fever, sore throat and a strawberry tongue

Scarlet fever

rare, potentially fatal multisystem disease caused by a GAS that elaborates a pyrogenic exotoxin- SpeA, B, or C that act as super antigens -children with chicken pox and elderly at risk -toxin causes the initiation of massive proinflammatory response -causes same symptoms as Staph where rapid multi organ failure leads to shock and death

GAS TSS

____ is most common cause of Necrotizing Infection II -contains a number of ___ ___ and elaborates ______ ______ _______. -begins with slight redness and swelling at site of infection

GAS M proteins; pyrogenic exotoxin A

a pseudomonas infection due to direct inoculation of bacteria in skin; can cause mild skin infection, like folliculitis -often infects burns, and wound due to injuries or surgery as well as bed sores

Primary skin Manifestations

due to pseudomonas bacteremia;

secondary skin manifestation

a secondary skin manifestation which is a result of bacterial invasion of dermal veins leading to hemorrhage of necrosis of skin -sore has a purple-black centre and is surrounded by a band of red

Ecthyma gangrenosum

S lugdunensis in Superficial wounds- full ID with AST only if _____ or ______ in deep wounds or sterile site- full ID with AST regardless of the amount growing in culture

pure; predominating

S lugdunensis Cat: Staphaurex: Tube Coagulase PYR Ornithine Use Vitekl OX MIC result or cefoxitin (30 ug) as a surrogate to report ______ -DO NOT DO _____ SCREEN CLSI uses same breakpoints as _____ ______

pos neg neg pos pos Oxacillin OX S aureus

causes Type III necrosis infection -infections from exposure of open wound to seawater with the bacteria -patients can develop widespread skin lesions with formation of hemorrhagic bull that progresses to necrosis

Vibrio vulnificus

causes Type III necrosis infection -found natural in brackish or fresh water- enter the skin through an open wound -also, if leeches used therapeutically

Aeromonas

Vibrio gram: MAC: Oxidase Nitrates to _______ salt____

Curved GNB/ comma, facultative anaerobe LF Pos nitrites loving

Aeromonas gram: Oxidase MAC

small gram negative coccobacilli, facultative anaerobe Pos LF

a gnb or gncb that can cause skin and soft tissue infections after animal bite- mostly dogs and cats -has 5 serotypes but mostly A and D causes disease in humans -virulence due to formation of capsule and toxin -skin infection starts with redness and swelling then cellulitis with purulent discharge -does not grow on MAC, oxidase pos, spot indole pos

Pasteurella multocida

severe skin and soft tissue infection due to anaerobic organism Clostridium; -can happen spontaneously in those with abdominal diseases- usually due to Clostridium septic

Clostridium Gas Gangrene

produces multiple toxins- alpha toxin the most virulent; -organism produces DNAse, hyaluronidase, and a hemolysin which al breakdown tissue- accompanied with a foul smelling gas- gas gangrene

Clostridium Perfringens

a rare direct cause of cellulitis and indirect skin manifestations

Neisseria meningitidis

causes dermal micro vessel thrombosis that rapidly leads to hemorrhagic skin necrosis, peripheral gangrene & shock

Purpura fulminans

Specimen collection: this type of specimen is not optimal; -should only be collected when tissue or aspirate can't be obtained -only for wounds that show obvious signs of infection or chronic wounds that are not healing -must cleanse the wound first to remove superficial debris by irrigating with ______ ______ -collect the specimen by gently rolling the swab over the surface of the wound approximately ____ times, focusing on ____ or inflamed tissue -Place swab in transport media like ____ or _____ -SUPERFICIAL SWAB SPECIMEN NOT APPROPRIATE FOR ________ CULTURE

Superficial swabs sterile saline five pus Amies; Stuarts ANO2

Best specimens for skin and soft tissues

Aspirates or Biopsies

For infected bite wounds: -aspirate pus from the infected wound Don't culture fresh bite wounds- will have normal rest flora introduced from the bite but cultures can't predict if these will cause infection

useful for the detection of an IV catheter-associated bloodstream; a short section of the catheter that had been under the skin is aseptically; cultured by rolling tip across the agar surface using sterile forceps

Intravascular Tips