end of SSTI + osteomyelitis Flashcards by amanda kastel

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

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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

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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)

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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

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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

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true or false

necrotizing fascitis is a nonpurulent SSTI

true

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explain what necrotizing fasciitis is

rare but severe destruction of superficial fascia and cutaneous fat

DANGEROUS - 20-50% mortality

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how many types of necrotizing fasciitis are there

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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

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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

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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

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cause (bacteria) of type 3 necrotizing fasciitis

clostridium perfringes infection

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are there any systemic symptoms in necrotizing fasciitis

yes - fever, chills, leukocytosis

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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

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true or false

necrotizing fasciitis may rapidly evolve into gangrene

treu

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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

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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

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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

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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

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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

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true or false

most of the time necrotizing fasciitis requires MULTIPL debridements (another 24-36 hours after the initial surgery)

TRUE

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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

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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

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define osteomyelitis

inflammation of the BONE MARROW and the surrounding bone associated with the infection

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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

end of SSTI + osteomyelitis Flashcards

(72 cards)