SSTIs and Osteomyelitis Flashcards
3 pyodermal infections of the epidermis/dermis?
Impetigo
Erysipelas
Ecthyma
What is impetigo usually caused by?
S aureus
What is erysipelas usually caused by?
Strep pyogenes
What is ecthyma usually caused by?
Strep pyogenes
How does erysipelas present?
Infection of the superficial skin (down to dermis) often caused by strep pyogenes, distinct leading edge
What is ecthyma?
Deep punched ulcer with yellow crusting affecting epidermis and dermis
Often affects lower legs, shins and dorsum of feet
3 infectious conditions affecting hair follicles?
Folliculitis
Furuncle
Carbuncle
What are folliculitis, furuncles and carbuncles most often caused by?
S aureus
Describe the progression from folliculitis -> furuncle -> carbuncle
Folliculitis = pustule formation around hair follicle, when extends down into root of hair = furuncle
Multiple furuncles = draining abscess formation = carbuncle
What is cellulitis?
Tender erythematous skin infection that extends right down to the fascia with no distinct leading edge
What is paronychia?
Swollen erythematous lesion surrounding the nail bed usually caused by s aureus or strep pyogenes
Pathogenesis of nec fasc?
Painful erythematous infection of skin which crosses fascia of underlying muscles causing compartment syndrome and subsequent muscle necrosis
High fever, sepsis
Features of SSTI that might make you think nec fasc rather than cellulitis?
Pain disproportionate to clinical signs Crepitus - gas gangrene High fever, sepsis Bullae or ecchymosis Tender beyond visible poorly demarcated borders
What is the emergency management of nec fasc?
Radical debridement
What bacteria often cause nec fasc?
Mixture of coliforms e.g. E. coli, anaerobes
Can be strep pyogenes
What specific blood test can be done to assess extent of nec fasc?
CK (compartment syndrome leading to rhabdomyelysis)
Management of non-complicated cellulitis?
Flucloxacillin
Or erythromycin, clarithromycin
What treatment is used for cellulitis with sepsis or facial cellulitis?
IV Co-amoxyclav
What is Ludwig’s angina?
Nec fasc of submandibular space
What is Fournier’s gangrene?
Nec fasc of scrotum or vulva
What are the 4 aetiological types of nec fasc?
1 = polymicrobial incl coliforms and anaerobes 2 = GAS/staph 3 = gram negative microbes (vibrio, aeromonas hydrophila) 4 = fungal incl candida
Who does type 1 nec fasc (polymicrobial anaerobes and coliforms) most commonly affect?
The immunocompromised / chronically diseased
Who can type 2 nec fasc (GAS/s aureus) affect?
Anyone of any health
Who does type 3 nec fasc (gram negs e.g. Vibrio spp, aeromonas hydrophila) affect?
Marine association so fisherman, swimmers in seawater etc
HIGHLY VIRULENT
What bedside test is used for suspected nec fasc?
Bedside finger test - incise 2cm down to deep fascia under local
Lack of bleeding, malodorous dishwater pus, lack of normal tissue resistance
Culture and gram stain this
Antibiotic management of nec fasc?
Start IV broad spectrum abx according to local guidelines, ensuring coverage of GAS/MSSA, anaerobes + coliforms and gram negatives
E.g. Meropenem + clindamycin
From superficial to deep, what are the 3 main layers of the skin?
Epidermis
Dermis
Subcutis
