May11 M1-Soft Tissue Infections Flashcards
layers of the skin and subcutaneous tissue
- epidermis (melanocytes and Langerhans immune cells)
- dermis (upper lower and hypo. follicles, glands, nerves, corpuscules Meissner’s and Pacini)
- subcutaneous tissue (FASCIA, blood vessels, nerves)
- muscle
uncomplicated vs complicated soft tissue infections
- uncomplicated = cellulitis, erysipelas, abscess, folliculitis, furunculosis, impetigo, ecthyma
- complicated = bigger wounds, inflected by humans or animals or surgical problem + affected by underlying state of pt (immunosuppressed, diabetic, etc.): includes necrotizing infections (NI), myonecrosis
- the more there is soft tissue (buttocks and perianal area), the easier it gets infected*
(exam) skin layers affected by cellulitis
epidermis and dermis
(exam) skin layers affected by erysipelas
dermis (lymphatics of the dermis)
(exam) skin layers affected by a skin abscess
- more often: epidermis and dermis
- sometimes: subcutaneous tissues and muscle
most common bug seen in the community (#1 cause of infections)
MRSA (staph aureus)
how do you treat an MRSA infection, or infection that you suspect to be ‘‘MRSA type’’
Septra
(exam) felon (hand infection of inoculation of compartmentalized fibrous septae of the hand): layers of skin affected
possibly all layers (including ligaments, tendon sheaths, bones)
(exam) paronychia (skin infection) affects what skin
skin over the mantle of the nail or of the lateral nail fold. can progress to felon (so all layers possibly)
(exam) tenosynovitis (hand infection, penetrating injury, painful extension of finger)
- volar surface and tendon sheath (is a penetrating infection)
- tendon (so deep)
most common organism causing tenosynovitis
staph aureus
(exam) human bites: skin layers affected
possibly all layers + joint space, muscle, etc.
(exam) #1 and #2 most common species in cat bite infections
- pasteurella spp
2. staph spp
(exam) #1 and #2 most common species in dog bite infections
- pasteurella spp
2. staph spp
(exam) #1 and #2 most common species in human bite infections
- strep viridans (alpha hemolytic)
2. strep pyogenes (GAS) and staph aureus
(exam) diabetic foot (ulcer) skin layers affected
can go from cellulitis (epidermis and dermis) to chronic osteomyelitis very hard to tx (all layers, bone)
necrotizing infections include what infections
- clostridial infections
- necrotizing fasciitis
- bacterial synergistic gangrene
- streptococcal gangrene
most common bacteria of NIs
skin bacteria
- staph aureus
- pseudomonas aeruginosa
* BUT ASSUME POLYMICROBIAL*
(EXAM) most frequent site of spontaneous NI
perineum (space between the anus and scrotum in the male and between the anus and the vulva in the female)
(EXAM) most frequent site of NI overall (includes everything, not just spontaneous. so wound, puncture, injury, etc.)
limbs
(imp?) gold standard for NI diagnosis
- tissue bx or some sort of culture
- high suspicion
(exam) skin layers affected by bacterial synergistic gangrene
epidermis and dermis
FASCIA IS OK. ONLY ABOVE FASCIA
(exam) necrotizing fasciitis (flesh eating disease): skin layers affected
-epidermis
-dermis
-fascia
(NOT MUSCLE)
(imp?) management of necrotizing fasciitis
radical debridement on surgery + broad spectrum Abx
(imp?) key thing GAS produces that makes it bad and key concept related to that
- produces exotoxin A, makes you septic. is a superantigen
- everyone responds differently (sick to a diff level) to a superantigen bc of genetics*
(imp?) what is the key thing that makes GAS dangerous
having an unbalanced immune response (too many pro-inflam signals, because of exotoxin A for example), and some people, bc of genetics, are more likely to have more pro-inflam signals
(imp?) key tx to a GAS infection
surgical debridement
(exam) skin layers affected by a clostridial cellulitis
-dermis
-fascia
-muscle
(NOT EPIDERMIS)
