skin and soft tissue infection

Question 1

things to consider

Answer 1

organism
host: diabetes, immunosuppression, predisposing factors e.g. atopic dermatitis
site:
environment: drug resistant strains, drug allergies

Question 2

impetigo

Answer 2

superficial skin infection
highly infectious
kids 2-5yrs

Question 3

impetigo organisms

Answer 3

staph aureus mostly

strep pyogenes

Question 4

impetigo features

Answer 4

multiple vesicular lesions on erythematous base
golden crust
usually exposed parts of body: face, extremeties

Question 5

impetigo predisposing factors

Answer 5

skin abrasions 
poor hygiene
atopic dermatitis
insect bites
chicken pox
minor trauma
burns

Question 6

erysipelas

Answer 6

infection of upper dermis

most commonly strep pyogenes

Question 7

erysipelas features

Answer 7

painful, red areas
distinct elevated borders
assoc fever
regional lymphadenopathy + lymphangitis

Question 8

erysipelas risk factors

Answer 8

pre-existing lymphodema
venous stasis 
obesity 
paraparesis 
DM

Question 9

cellulitis

Answer 9

diffuse skin infection involving dermis and epidermis

staph a and strep pyogenes
possible source bacteraemia

Question 10

cellulitis features

Answer 10

spreading erythematous area with no distinct borders
fever
regional lymphadenopathy and lymphangitis

Question 11

cellulitis predisposing factors

Answer 11

DM
lymphadema
tinea pedis

Question 12

cellulitis and erysipelas Mx

Answer 12

combination anti-staph and anti-strep antibiotic

extensive disease: admission for IV antib and rest

Question 13

hair assoc infections

Answer 13

Folliculitis
Furunculosis
Carbuncles

Question 14

folliculitis

Answer 14

circumscribed pustular infection of hair follicle
up to 5mm diameter
staph aureus

Question 15

folliculitis presentation

Answer 15

small red papules
central area of purulence may rupture and drain
typically found head, back, buttocks

Question 16

folliculitis Rx

Answer 16

none

topical antibiotics

Question 17

furuncolosis

Answer 17

single hair follicle-associated inflammatory nodules
boils
staph aureus

Question 18

furunculosis features

Answer 18

extends into dermis and subcut tissue
may drain purulent material
usually affects moist, hairy, friction prone areas: face, axilla, buttocks

Question 19

furunculosis Rx

Answer 19

none
topical antib
oral antib

Question 20

furunculosis risk factors

Answer 20

DM 
atopic dermatitis
obesity 
kidney disease
corticosteroid use

Question 21

carbuncle

Answer 21

infections extends to involve multiple furuncles

multi-sepatated abscess

Question 22

carbuncle features

Answer 22

purulent material multiple sites
fever
multi-septated abscess
often back, neck

Question 23

carbuncle Rx

Answer 23

hospital
surgery
IV antib

Question 24

necrotising fasciitis predisposing factors

Answer 24

DM
surgery 
trauma 
peripheral vascular disease
skin popping

Question 25

necrotising fasciitis T1

Answer 25

mixed aerobic and anaerobic infection diabetic foot infection, Fournier's gangrene ``` strep staph enterococci gram = bacilli clostridium ```

Question 26

necrotising fasciitis T2

Answer 26

mono-microbial strep pyogenes

Question 27

necrotising fasciitis features

Answer 27

``` rapid onset erythema extensive oedema pain anaesthesia over infection skin necrosis, heamorrhagic bullae systemic: fever, hypotension, tachycardia ```

Question 28

necrotising fasciitis management

Answer 28

urgent surgical review - plastics for fasciotomy

Question 29

necrotising fasciitis antibiotics

Answer 29

broad spectrum flucloxacilin gentamicin clindamycin benzyl penicillin

Question 30

pyomyositis

Answer 30

purulent infection within striated muscle often forms abscess infection often 2ry to seeding damaged muscle

Question 31

pyomyositis features

Answer 31

fever pain woody induration of affected muscle

Question 32

pyomyositis organism and common sites

Answer 32

staph aureus common sites: thigh, calf, arms, gluteal region, psoas muscle

Question 33

pyomyositis predisposing factors

Answer 33

``` DM HIV IVDU rheumatological disease malignancy liver cirrhosis ```

Question 34

septic bursitis

Answer 34

infection often from adjacent skin infection most common s.aureus

Question 35

septic bursitis risks

Answer 35

``` alchohilism RA DM IVDU immunosupressino renal insufficiency ```

Question 36

septic bursitis features

Answer 36

peribursal cellulitis swelling, warmth fever pain on movement

Question 37

infection tenosynovitis

Answer 37

infection of synovial sheaths surrounding tendons staph a streptococci

Question 38

infection tenosynovitis: presentation

Answer 38

erythematous fusiform swelling finger held in semiflexed position pain finger extension tenderness over length tendon sheath

Question 39

infection tenosynovitis Mx

Answer 39

empiric antib | hand surgeon review

Question 40

what are toxin mediated syndromes often due to

Answer 40

superantigens - group pyrogenic exotoxins

Question 41

toxin mediated syndromes pathophys

Answer 41

superantigens bypass APC and bind directly to T cells massive burst cytokine release: endothelial leakage, haemodynamic shock, multi-organ failure

Question 42

toxin mediated syndormes: organisms

Answer 42

staph a: TSST1, ETA, ETB strep pyogenes: TSST1

Question 43

which TSS organism is assoc w tampons

Answer 43

staphylococcal TSS

Question 44

staphylococcal TSS diagnostic criteria

Answer 44

``` fever hypotension diffuse macular rash 3+ involved: liver, muscular, blood, renal, GI, CNS isolation staph a production TSST1 by isolate ```

Question 45

streptococcal TSS

Answer 45

usually assoc w prescence of strep in deep seated infection e.g. erysipelas, necrotising fasciitis urgent surgical debridement

Question 46

TSS Rx

Answer 46

``` IV fluids remove offending agent e.g. tampon inotropes IV Ig antib - clindamycin, vancomycin ```

Question 47

panton-valentine leucocidin toxin

Answer 47

staph a | recurrent boils, heamorrhagic pneumonia

Question 48

panton-valentine leucocidin toxin antibiotica

Answer 48

vancomycin, linezolid

Question 49

staphylococcal scalded skin syndrome

Answer 49

Infection due to a particular strain of staph aureus producing the exfoliative toxin A or B

Question 50

cellulitis antibiotics

Answer 50

1. fluclocacillin 2. clarithromycin (penicillin allergy) if pregnant - erythromicin