090514 osteomyelitis Flashcards
osteomyelitis
bone infection
categories of osteomyelitis
heamtogenous-from seeding of bone related to previous bacteremia
direct implanation-from penetrating injury
continguous-from direct spread of bacteria from an overlying wound or pressure ulcer
infection of prosthetic device-device implanted in bone
diff types of osteomyelitis with regards to how commonly you get them at what age
hematogenous ostemyelitis is more common in children
continugous and prostehtic infec more common in adults
when step on nail, which organisms can be implanted in bone?
Pseudomonas aeruginosa
pathogens causing hematogenous osteomyelitis
S. aureus Strep species gram negatives Mycobastcterium tuberculosis Salmonella species
pathogens causing contiguous osteomyelitis
S aureus gram negatives Strep species anaerboes Candida species
pathogens causing prostehtic joint infections of osteomyleitis
COAGULASE NEGATIVE staph
S aureus
gram negatives
Strep species
does osteomyelitis often cause chronic infections that are difficult to eradicate?
yes
damage to the periosteum can result in
pieces of dead bone (sequestrum) or new external bone (involucrum) local abscesses (brodie's abscesses)
for diagnosis of osteomyelitis, what imaging can be used?
XRs not good for early infections, may be effective 50% of the time at later infections
Bone/WBC scans and MRI are good
how can you determine the bacteria causing osteomyelitis
bone biopsy blood culture (if hematogenous osteomyelitis)
swab culture from open ulcer vs bone biopsy of bone with osteomyelitis underneath–what do they show about the bacteria?
the bacteria in the two samples may be entirely different
treatment of infections of prosthetic materials
are particularly difficult–oftentimes the protehsis has to be taken out
where can biofilms develop?
bone or prosthetic material (particularly on hard surfaces)
organisms in biofilms are
different from those of planktonic, or suspended, organisms
standard treatment for osteomyelitis
generally 6 wks IV antibiotics ( in some cases months of oral antibiotics may be needed, like for prothetic joint infec. *note: sometimes, even after 6 months of oral antibiotics, a prosthetic joint will still have to be removed)
if antibiotics alone don’t work, surgery may be needed to remove sequestra or protheses
what antibiotic is very useful for treating biofilm organisms?
rifampin
in the case of an ulcer that is open and you can actually see bone through it-how can you treat?
surgeon would have to put covering over the bone so new organisms can’t keep growing over the bone-otherwise you would get resistant organisms and antibiotics wouldn’t work
