Osteomyelitis Flashcards
categories of osteomyelitis
hematogeneous, direct implantation, contiguous, infection of prosthetic device
hematogeneous osteomyelitis
results from seeding of bone from previous bacteremia, more common in kids
direct implantation osteomyelitis
resulting from penetrating injury
contiguous osteomyelitis
results from direct spread of bacteria from an overlying wound or pressure ulcer, more common in adults (eg nail, diabetic foot ulcer)
infection of prosthetic device
results from infection of prosthetic material implanted in bone w/ spread of organisms into adjacent bone, more common in adults
hematogeneous pathogens
staph aureus, strep spp, gram-negatives, TB, salmonella in sickle cell pts
direct implantation pathogens
pseudomonas in nail injuries w sneakers
contiguous pathogens
s. aureus, gram-negatives, strep spp, anaerobes, candida
prosthetic joint infection pathogens
coagulase negative staphylococci, s. aureus, gram-negatives, strep spp
general characteristics of osteomyelitis
can last decades, can cause chronic infections difficult to eradicate. damage to periosteum can result in pieces of dead bone or new external bone formation, localized abscesses. X-rays aren’t sensitive for it, use Bone/WBC scans or MRI, bone biopsies or blood cultures
more characteristics of osteomyelitis
cultures of open ulcers over contiguous osteomyelitis are unreliable b/c bacteria under maybe be different. sometimes can’t do biopsy or culture is negative so use empiric treatment. prosthetic infections are difficult to treat, may need to remove prosthesis. biofilms may develop, make infections harder to treat
characteristics of biofilms
adhere to hard surfaces, frequently microorganisms are imbedded in slime/extracelular polymeric substance/glycocalyx. more likely resistant to abx.
osteomyelitis treatment
6 weeks IV or months of oral abx. maybe surgery. RIFAMPIN useful for biofilms. abx only useful if bone is covered by tissue, otherwise new organisms invade bone continuously
