Osteomyelitis Flashcards
OSteomyelitis
Infectious or non-infectious
We talk about infections
Progressive destruction of bone and formation of sequestra
Inflammation of bone and/or bone marrow space
Etiology and microbiology
Hematogenous…extension from soft-tissue infection…direct inoculation into bone
Staph aureus is the most common organism overall
Children vs. adults
Children - acute hematogenous…better overall prognosis due to blood uspply and actively remoduling bone
Adults - contigous spread or direct inoculation…more chronic…more often ofreign bodies…more difficult to tx
Acute hematogenous osteomyelitis
Mostly in infants or children or IV drug abuses
Most often in metaphysis of long bones (distal femur and proximal tibia)
Often preceded by minor trauma
Micro bio of acute hematogenous
Staph is most common
Group A, pneumocossu, group B (neonates)
Kingella kingae - younger with stomatitis
Salmonella - sickle cell
Heamophilus - uncommon)
Other more in IV drug abusers - E coli, Candida, pseudomonoas
Acute hematogenous presentation and untreated
Localized, point tenderness, transient fever, maybe swelling
Spread into epiphysis and joint space
Subperiosteal abscess between periosteum and bone
Brodie’s abscess - localized bone abscess
Bone necrosis and formation of sequestra
Tx of acute hematogenous osteomyelitis
Drainage
Debridement of sequestra
Anti biotics
Children - at staph auerus and gram -…4-6 weeks and switch to oral
Adults - staph aureus…if IVDA, then add gram neg…more often parenteral through entire course
Narrow based on culture results
Osteomyelitis due to local extension or direct incoulation
Diabetic foot ulcer, decubitus ulcer, cellulitis or myosistis
Contaminted open fracture…depends on level of contamination (think dirt bike vs. car)
Nosocomial infection of operative site
MIcrobio of local or direct inoculation
More likely to be poly than hematogenous
MRSA most common
Nosocomial - Staph epidermidis and other skin flora…pseudomonas and other gram negs
Open fracture - MRSA, aerobic gram-neg bacilli (like E coil, enterbacter, psudomonas), enterococcus, anaerobes )think soil), fungi
Presentation of local or direct inoculation
Often present iwth inadequate response to therapy for SSTI or return of sx
Drainage from surgical site if nosocomial
contaminated open fracutre may not become apparent until several months after injury…non-union of fracture, sinus tract formation, dehiscence
May also have fever other systemic sx
Tx of local or direct incoluation
Surfical drainage nad removal of foreign bodies
Debridement of non-viable bone or sequestra
Soft tissue debridement
ABs - direct at staph areus but combine broad spectrum is contaminated open fracutrs and nosocomial infecion
4-6 week minimum
Chronci osteomyelitis
Un-treated actue
Lacks systemic sx
May need debridement to cure
Need 6 mos or more of ABs
May need chronic suppressive ABs
Vertebral osteomyelitis
More often hematogenous
IVDU
Staph aureus or coag neg staphyloccci
Gram-negs - pseudomonas
Candida
Myco TB
Workup and dx of osteomyellitis
Inflam markers signiciantly elevated during acute osteomyelitis but not during chronic
Blood cultures more likely in acute
Culture of bone/abscesss material is best but may be neg in chronic
Gram stain and cblood culture Kingella)
Radiological
Plan film - lytic lesions, periostea lelevation, periosteal new bone formation…10-14 days after
MRI - most sensitive
Low marrow intesntiy on T1..bright on T2
Periosteal elevation/abscess
Enahnement and abscess formation (with gadolinium)
Imaging modaliyt of choice
Bone scan - better sensitivity than plain but les than MRI…less specific
Low resolution
Helpful if multifocal suspected
incrreased uptake in areas of increased bone turnover
