Skin and soft tissue infections Flashcards
are superficial SSTIs typically caused by gram positive or gram negative organisms?
gram positive
what typically causes impetigo?
strep pyogenes
staph aureus
what typically causes erysipelas?
strep pyogenes
what typically causes folliculitis and furuncles?
staph aureus
what typically causes cellulitis?
strep pyogenes
staph aureus
hot tub folliculitis is caused by what organism? what is the gram stain / morphology?
pseudomonas aeruginosa
gram negative rod
why is the history of CABG pertinent in a patient presenting with cellulitis in the leg?
scar tissue
high risk of lymphedema with venous skin graft
what medications are used for non-purulent cellulitis?
- first generation cephalosporin
- anti-staphylococcal penicillins
what medications are used for purulent cellulitis? what is critical for treatment?
- IV vancomycin (MRSA)
- TMP-SMX oral
- clindamycin (variable)
- DRAINAGE IS KEY
what medication is used for hot tub folliculitis?
no medication needed!
what are the microbial etiologies of necrotizing fasciitis / fasciitis?
- clostridium perfringens
- group A strep (pyogenes)
- polymicrobial (gram neg rods + gram pos cocci)
- MRSA - new and rare
what are the clinical features of necrotizing cellulitis / fasciitis?
- severe constant pain out of proportion to findings
- bullous lesions
- systemic toxicity
- gas in soft tissues
- rapid spread
what is the sourcs for clostridium infection? which is most common?
- tissue trauma (surgery) - MOST COMMON
- bacteremic spread (colon)
what is the gram stain for clostridium?
gram positive
which organism is responsible for gas gangrene?
clostridium
what organisms can cause chancriform / chronic nodular lesions?
- sporothrix
- mycobacterium marinum - swimming pool granuloma
- bacillus anthracis
- francisella tularensis
- nocardia, leishmania, blastomycosis dermatitis
what are the routes for septic arthritis? which is most common?
- hematogenous - most common
- direct inoculation
- contiguous spread
what are the risk factors for septic arthritis?
- RA
- steroid use
- DM
what are the microbial etiologies of septic arthritis? which is most common? what if it is a prosthetic joint?
staphylococcus aureus - most common
strep (A and B)
gram negative
prosthetic joint - coagulase negative staph
clinical features of septic arthritis
- monoarticular 80-90%
- pain, loss of function, swelling, redness
- fever 60-80%
- focal joint tenderness, inflammation, effusion, limited and painful motion
- WBC over 60,000
management of septic arthritis
- systemic antimicrobials
- drainage
what are the two possible syndromes associated with gonococcal infections?
- gonococcal arthritis
- tenosynovitis, dermatitis, polyarthralgia without purulent joint infection
which antibiotic(s) is/are used for n. gonorrhea?
third gen ceph or fluoroquinolone
which antibiotic(s) is/are used for s. aureus?
nafcillin
first generation ceph or vancomycin
which antibiotic(s) is/are used for GAS?
PCN or ceph
which antibiotic(s) is/are used for gram negatives?
ceph, FQ, carbapenems
contiguous osteomyelitis is associated with what etioloties?
- post trauma
- peripheral neuropathy
- vascular insufficiency
- pressure ulcers
what is the main microbial etiology of osteomyelitis?
staph aureus
what diagnostic techniques are used to diagnose osteomyelitis? which is most sensitive and specific?
- bone probe
- MRI (most sensitive and specific)
- bone biopsy
when should pseudomonas aeruginosa be considered in a case of osteomyelitis?
puncture wound
what is the main microbial etiology of vertebral osteomyelitis / spondylodiskitis?
s. aureus
what type of abx are used in acute osteomyelitis?
anti-staph
what is the main treatment for chronic osteomyelitis?
surgery
