SSTI, BJ IDBR Flashcards
What are the two major mechanisms by which osteomyelitis occurs?
Continugous Innoculation = contaminate bone directly through ulcer adjacent to bone, the integrity of cortex breached. Seen in DFI, open fractures, surgical procedures. (2) Hematogenous seeding - common for acute long bone osteomyelitis in children, and vertebral osteomyelitis in adults. Site of infection elsewhere.
TX of staphylococcal prosthetic joint infection?
2-6 weeks of pathogen-specific IV therapy + rifampin 300-450 BID followed by rifampin + oral drug for total 3 months.
If TKA - 6 months. Oral companion drug include FQ.
Common organism associated with contiguous-focus osteomyelitis?
Polymicrobial, but most common is staph aureus
most common pathogen associated with open fracture oseomyelitis?
Staph aureus, CoNs, aerobic GNB
what test has the highest PPV for osteomyelitis?
Probe to bone test
what should you know about plan radiographs for osteomyelitis?
abnormalities may not be apparent up to 2 weeks in most types of osteomyelitis
what should you know about technetium Tc99m methylene diphosphonate bone scan for osteomyelitis?
Low specificity patiuclarlay with other bone diseases like neuropathic bone disease or radiation necrosis
which is the best diagnostic test outside of probe to bone/biopsy for orthopedic hardware?
CT/MRI may be degraded. Gallium Ga 67 citrate especially for diskitis, and when MRI cannot be used
what is gold standard for osteomyelitis?
deep bone culture/bone biopsy
when does broad spectrum empirical therapy need to precede surgical therapy?
Concomitant soft tissue infection, sepsis syndrome with osteomyelitis,
the general idea of treatment for chronic osteomyelitis after debridement and removal of orthopedic hardware?
IV/highly bioactive PO for 4-6 weeks with success rates around 80%
the general idea of treatment duration for acute hematogenous cases with vertebral osteomyelitis?
4-6 weeks
Options when orthopedic hardware cannot be removed at time of surgical debridement owing to need to stabilize fracture?
(1) IV therapy, with long term PO suppressive therapy. (2) FQ+rifampin after IV therapy w/o suppressive therapy (studied with staphyloccal infection of fracture fixation device)
Tx of relapse of infection with retained hardware?
remove orthopedic hardware and administer IV/PO for 4-6 weeks
general principles of treatment for chronic osteomyelitis?
source control via debridement/removal of hardware, management of dead space and adequate soft tissue coverage via flaps/grafts/antimicrobial beads, assess vascular supply
Antibiotic duration for DFI?
Parenteral therapy for moderate/severe. PO for low severity. 1-2 weeks for mild, 2-3 for moderate/severe.
what imaging studies used for DFI?
all patients with new DFI have plain radiographs. MRI if soft tissue abscess/osteomyelitis, If MRI contraindicated, radionuclide bon scan and labeled white blood cell scan.
How long would you treat for DFI after radical resection?
If no remaining infected tissue, 2-5 days. if persistent infected/necrotic bone, >4 weeks. (weak/low)
what are risk factors for pseudomonas infection?
high local prevalence, warm climate, drugs, frequent exposure of foot to water
what is a two stage exchange arthroplasty? problem?
implants removed, infected tissues debrided, temporary antibiotic impregnated space placed (stage 1). After weeks of IV antibiotics, reimplantation (stage 2). Between stages 1 and 2, risk of abx toxicity and pain due to lack of functioning joint
what is a one stage exchange arthroplasty?
infected prosthesis removed, infected tissues debrided, and new prosthesis implanted during the same procedure
most common organism in infectious arthritis?
staph aureus
most common organisms after manipulation of joint after surgery?
coagulase negative staphylococci
most common pathogen infectious arthritis in young patients?
neisseria gonorrhoeae
what patient population do you suspect infections due to gram negative bacteremia?
more common in elderly
