end of SSTI + osteomyelitis Flashcards
what do we want to cover empirically for SEVERE CELLULITIS (hospitalized) for purulent vs non-purulent
purulent - MRSA
non-purulent
for moderate infection - at least cover MSSA and strep
for penetrating trauma or IV drug user, or MRSA evidence anywhere else - cover MRSA and strep
if immunocompromised or have a severe infection - use BROAD SPECTRUM like vancomycin + pipercillin-tazobactam
5 best empiric drugs for purulent, severe cellulitis (hospitalized)
what 2 other things could we consider if circumstances are appropriate
want to cover MRSA
vanco
dapto
linezolid
ceftaroline
telavancin
could consider oravancin or dalbavancin bc just need 1 injection and they’re covered for 10-14 days (very long acting glycopeptides) and they can be discharged, but they’re VERY expensive
pt has nonpurulent moderate cellulitis
what do we want to minimally cover and what can we use
MSSA and strep
cefazolin (1st gen) or ceftriaxone (3rd gen)
pt has nonpurulent cellulitis but they are an IV drug user, or have experienced penetrating trauma
what do we want to cover and what is the drug used
cover MRSA + Strep
use vancomycin
pt has cellulitis but is immunocompromosed or has a SEVERE infection
what treatment do we use
use broad spectrum:
vanco + pipercillin-tazobactam
want to cover anaerobes + pseduomonas
true or false
necrotizing fascitis is a nonpurulent SSTI
true
explain what necrotizing fasciitis is
rare but severe destruction of superficial fascia and cutaneous fat
DANGEROUS - 20-50% mortality
how many types of necrotizing fasciitis are there
3
explain the cause of type 1 necrotizing fasciitis and when it usually occurs
caused by a polymicrobial infection - aerobic AND anaerobic bacteria
usually occurs after surgery or trauma
explain the cause of type 2 necrotizing fasciitis
MONOmicrobial - unlike typ 1
caused usually by group a strep (strep pyogenes) or other beta hemolytic strep
of the 3 types of necrotizing fasciitis, which is the most severe and most difficult to treat
type 3
gas gangrene muscle necrosis
advances rapidly over just a few hours
cause (bacteria) of type 3 necrotizing fasciitis
clostridium perfringes infection
are there any systemic symptoms in necrotizing fasciitis
yes - fever, chills, leukocytosis
what does an area affected by necrotizing fasciitis look like
hot swollen and red, skiny skin bc so tight, very tender and painful. the area will sweat a lot and then be filled with bullae filled with a clear liquid
the pain will be out of proportion to what the infection looks like - bc of the destruction under the surface
the wound of the infected area will feel hard
true or false
necrotizing fasciitis may rapidly evolve into gangrene
treu
TRUE OR FALSE
antibiotics can cure a necrotizing fasciitis infection
FALSE
surgical debridement is necessary for all pts with suspected necrotizing fasciitis
antibiotics alone will not even be close to curing - you need surgery immediately
true or false
blood cultures are not used in necrotizing fasciitis
false
blood cultures and deep tissue cultures are sent to help guide antimicrobial therapy
when treating necrotizing fasciitis with antibiotics (+ surgery) what do we need to cover EMPIRICALLY and what is the treatment
pipercillin tazobactam + vancomycin
bc we need to cover MRSA + pseudomonas + anaerobes
NEED VERY BROAD COVERAGE
once the necrotizing fasciitis culture is back, the pathogen was determined to be Group A strep
what is appropriate treatment and explain
penicillin + clindamycin
the clindamycin is actually not used for its properties against strep. it’s used because it suppresses and binds the streptoccoal TOXIN, having immunomodulatory properties and helping with systemic symptoms
also, it covers RMSA
as mentioned, for necrotizing fasciitis we give pipercillin-tazobactam + vancomycin empirically
what is a concern with this
increased risk of acute kidney injury when they’re combined - need to monitor renal function and changes to serum creatinine
also therapeutic drug monitoring for vancomycin
true or false
most of the time necrotizing fasciitis requires MULTIPL debridements (another 24-36 hours after the initial surgery)
TRUE
In necrotizing fasciitis, antimicrobial therapy must be administered until all 3 of these criteria are met:
-debridement is no longer needed
-clinical improvement is observed
-pt has no fever for AT LEAST 48-72 hours
31 year old female presents to ED with extremely painful case of cellulitis with no sharply demarcated regions
temp is 101
WBC is 15,000
ED physician is worried about necrotizing fasciitis. what empiric antibiotics should be initiated, assuming NKA
vancomycin + pipercillin-tazobactam
need to cover MRSA, pseudomonas, and anaerobes
define osteomyelitis
inflammation of the BONE MARROW and the surrounding bone associated with the infection
TRUE OR FALSE
osteomyelitis can affect ANY BONE and can affect ALL AGE GROUPS
true
if pt presents with recent onset of osteomyelitis - only been day - 1 week, what is prognosis if managed appropriately
good prognosis
if osteomyeletis persists for a long duration and the bone becomes avascular and necrotic, what is the prognosis
difficult to eliminate - amputation is really the only cure
2 causes of osteomyelitis and differentiate them
hematogenous spread and contiguous spread
hematogenous spread - spreads from a distant sight through the BLOODSTREAM and to the bone
contiguous spread - spreads from an adjacent tissue and to the bone
which bacteria is responsible for 80% of osteomyelitis cases caused by hematogenous spread?
what is the cause of contiguous spread
STAPH AUREUS
staph aureus is also most common cause of contiguous spread, BUT it can be polymicrobial (so need broad coverage!!)
a diabetic foot infection is example of osteomyelitis from hematogenous or contiguous spread
contiguous
what ages is hematogenous spread vs contiguous spread of osteomyeltis most common
hematogenous - common in less than 16 years (children)
contiguous - common in greater than 50 yrs
endocarditis caused by staph aureus gets into the bloodstream and causes osteomyelitis
is this an example of hematogenous spread or contiguous spread
hematogenous
empirically, what should ALWAYS be covered and what can be added depending on risk factors?
STAPH SHOULD ALWAYS BE COVERED
depending on risk factors, may need to cover others like strep, e. coli, pseduomonas, gram negatives, anaerobes
pt is a newborn
which organisms should minimally be covered in empiric therapy for osteomyelitis
staph
group B strep
e. coli
pt is a child less than or equal to 5
what organisms should minimally be covered for empiric therapy for osteomyelitis
staph aureus or strep
children greater than 5 and adults
what organisms should minimally be empirically covered for osteomyelitis
just staph aureus
pt is an IV drug user
what organisms should be covered empirically for osteomyelitis
staph aureus + pseudomonas
pt is post op or trauma
what organisms should be covered empirically for osteomyelitis
gram positives and gram negatives - BROAD SPECTRUM
(obv including staph aureus)
pt has vascular insufficiency
what organisms should be covered empirically for osteomyelitis
gram positives and negatives and anaerobes
general clinical presentation of osteomyelitis
4 cardinal signs, fever, chills, malaise, swelling
4 lab values in osteomyelitis
high WBC for acute
elevated ESR and CRP in chronic
only 50% of pts will have positive blood cultures
easiest way to diagnose osteomyelitis
what are 2 other ways and when can they start to detect osteomyelitis
probe to bone is easiest way
others are x-ray (can only detect 10-14 days after onset - wont detect newer infections) and MRI (better - can detect as early as 1 day after onset)
what is done to obtain cultures of osteomyelitis so we can streamline our empiric therapy
bone biopsy
2 general methods of managing osteomyelitis
surgical intervention (debridement to remove necrotic tissue and bone)
antibiotics
antibiotic duration of treatment for osteomyelitis and why
4-6 weeks (at least) – bc the bones are hard to penetrate
GIVEN IV
explain the general route and dose that antibiotics for osteomyelitis are given
IV and at high doses
giving antibiotics early into an osteomyelitis infection has been shown to….
lessen the need for surgical debridement
in what cases would we delay antibiotics in osteomyelitis patients
in stable patients
we would wait until the cultures and susceptibility come back and not start empiric therapy - in order to target appropiately
empiric therapy for osteomyelitis must ALWAYS COVER
STAPH AUREUS
whether it’s MRSA or MSSA depends on pt risk (mentioned earlier)
empirically treating osteomyelitis:
if the local susceptibility to resistant staph aureus is greater than ___________%, we should empirically treat MRSA and not MSSA
10%
in IV drug users for osteomyelitis we empirically cover staph +……..
pseudomonas
in post op/trauma patients for osteomyelitis, we empirically cover staph +……
gram negatives
in pts with vascular insufficiency we empirically cover staph +……….. for osteomyelitis
gram negatives+/-anaerobes
pathogen is MSSA
what therapy to use for osteomyelitis
nafcillin or oxacillin
cefazolin
pathogen is MRSA
what therapy to use for osteomyelitis
vanco
dapto
linezolid
pathogen is gram negative organisms (inc pseudomonas(
what therapy for osteomyelitis
lot of options
ciprofloxacin
levofloxacin
ceftazidime
cefepime
pipercillin-tazobactam
pathogen is an anaerobe
what therapy for osteomyelitis
metronidazole (only is not using pipercillin-tazobactam)
pipercillin-tazobactam brand name
zosyn
2 things to monitor when giving nafcillin or oxacillin for MSSA osteomyelitis
liver function tests (LFTS)
interstitial nephritis
what to monitor when giving vanco/dapto/linezolid for MRSA osteomyelitis
vanco - therapeutic drug monitoring, renal function, watch for infusion reactions
daptomycin - monitor creatinine phosphokinase
linezolid - monitor platelets and interaction with SSRIS (serotonin syndrome)
what to monitor when giving metronidazole for osteomyelitis caused by anaerobes (if not giving zosyn)
disulfiram-like reaction
are there any situations where we can use oral antibiotics for osteomyelitis rather than IV?
explain
yes.
if the pt is confirmed to have osteomyelitis, had a clinical response when starting the IV ab’s, there is a suitable oral agent available that can effectively target the pathogen, and assured that the patient will be adherent
oral antibiotic use in osteomyelitis is well studied in _________ but there are limited studies in _________
well studied in CHILDREN
there are limited studies in adults, but still good evidence
(new england journal of medicine reported on it)
how frequently should WBC be monitored for an osteomyelitis infection
weekly
how frequently should CRP or ESR be monitored for an osteomyelitis infection
weekly
important consideration when weekly monitoring CRP or ESR for osteomyelitis infection
the values may not go back to normal range until after several weeks of treatment
how frequently should clinical signs of inflammation be monitored for an osteomyelitis infection
daily during therapy
important considerations when giving PO antibiotics for outpatient therapy for osteomyelitis
compliance is CRUCIAL for successful treatment - must educate
46 year old man diagnosed with osteomyelitis on 5th digit of left foot
refusing amputation and wants to try antibiotics to cure the infection. culture is showing MSSA
what is most appropriate therapy management and what should be monitored
start nafcillin and monitor weekly CPR/ESR
(or oxacillin or cefazolin)
NOT vanco or dapto - too broad
true or false
CPK’s should be monitored when starting cefazolin for MSSA osteomyelitis
FALSE
CPK’s should be monitored with daptomycin (for MRSA)
68 year old male presents with foul smelling diabetic foot infection on right heel.
wound was positive for probe to bone and MRI confirmed osteomyelitis.
received surgical debridement and cultures sent in
what is most appropriate empiric therapy
need to cover STAPH
has diabetic risk factor (vascular insufficiency) – need to cover gram negatives and anaerobes
so therapy is vancomycin + pipercillin-tazobactam
WHEN WE USE PIPERCILLIN-TAZOBACTAM DO NOT USE METRONIDAZOLE!!!!! NEVER DOUBLE COVER ANAEROBES
