21- Osteomyelitis Flashcards
osteomyelitis is classified based on
- mechanism of infection (non/hematogenous)
- duration of illness (acute/chronic)
acute osteomyelitis
has symptoms duration of a few days or weeks and has no sequestra
sequestra
pieces of necrotic bone that separate from viable bone due to elevated medullary pressure due to bone marrow inflammation. These are seen on Xray
chronic osteomyelitis
a long standing infection over months or years, with sequestra
THE PRESENCE OF A SINUS TRACT IS PATHOGNOMONIC
non hematogenous osteomyelitis
occurs as a result of contiguous spread of infection to bone from adjacent soft tissues or joints
- or via direct inoculation of infection to the bone due to trauma or surgery
hematogenous osteomyelitis is
Occurs more in which age?
Is it mono or polymicrobial
is caused by microorganisms that seed the bone in the setting of bacteremia
- occurs mostly in children
- most common form in adults is vertebral osteomyelitis (males>50, drug users)
- is usually monomicrobial (S aureus)
etiology of non hematogenous osteomyelitis
polymicrobial or mono.
S aureaus (and MRSA), coagulase - staphylococci, aerobic gram - bacilli
- less common: corynebacteria, fungi, mycobacteria
symptoms of acute osteomyelitis
gradual onset of symptoms over several days, dull pain at site with/out movement
- tenderness, warmth, erythema, swelling, fever, rigors
SX of chronic osteomyelitis
FEVER IS USUALLY ABSENT
- pain, erythema, swelling, draining sinus tract
intermittent flares of pain and swelling
dx of chronic osteomyelitis
deep extensive ulcers that fail to heal after several weeks (esp when lesions lie over bony prominences)
- non healing fractures
T/F osteomyelitis can be due to P aeruginosa
T, when it develops in the foot post nail puncture
initial assessment of suspected osteomyelitis should include
- probing the bone with a sterile blunt metal tool
- this test is pos if you have a hard gritty surface
- this test isnt very reliable
- the test is done in the setting of diabetes foot ulcers
T/F symptoms of hematogenous vs non hematogenous osteomylitis are indistnguishable
T
complications of osteomyelitis are
sinus tract formation contiguous soft tissue infection abscess septic arthritis systemic infection bony deformity fracture
sx of non hematogenous osteomyelitis
- new or worsening musculoskeletal pain
- cellulitis
- diabetic ulcers probe to bone
dx of osteomyelitis
culture from involved bone biopsy
clincial and radiological findings (for pts with >2 weeks symptoms use x ray, for <2 weeks symptoms use advanced imaging)
T/F open biopsy is preferred to needle biopsy
T
when do you need surgical debridment for osteomyelitis
decubitus ulcers, wounds with compromised vasculature
ddx for osteomyelitis
soft tissue infection charcot arthropathy osteonecrosis gout fracture bursitis bone tumor sickle cell vaso occlusive pain crisis synovitis Complex regional pain syndrome
screening for osteomyelitis is done by which test
probe bone test
Is positive if a hard gritty surface is felt
RF for non hematogenous osteomyelitis
poorly healing tissue wounds, previous joint replacing surgery, peripheral vascular disease, peripheral neuropathy, diabetes
RF for hematogenous osteomyelitis
endocarditis, indwelling devices, orthopedic devices, injection drug use, hemodialysis, sickle cell dx
the pathogens found in hematogenous osteomyelitis in drug users are
P aeruginosa
Serratia marcescens
What is a brodie abscess
is a region of suppuration and necrosis encapsulated by granulation tissue within a rim of sclerotic bone
Occur with subacte/chronic osteomyelitis in metaphysis of long bones in pts <25 y
Usually of hematogenous origin
Often with S aureus (pain lasting wks to mons with/out fever)
Most common site is distal tibia (then femus, fibula, radius ulna)
Shows as a single lesion near metaphysis radiographically
If metal hardware is present, you cant put the pt in an MRI, how do you image for osteomyelitis
nuclear test imaging
How to ID pathogen in osteomyelitis
bone biopsy, cultures from swabs or material from needle puncture should NOT BE USED
T/F percutaneous bone biopsy should be done through intact bone
T
T/F pts with osteomyelitis involving the hip, vertebrae, or pelvis tend to manifest few signs or symptoms other than pain
T
T/F in the setting of chronic osteomyelitis, leukocytosis is uncommon, the ESR/CRP can be elevated or normal
T
T/F long bone osteomyelitis can present as septic arthritis of the knee hip or shoulder
T
This occurs if infection within the metaphysis (most common site of infection in long bone osteomyelitis) breaks through the bone cortex leading to discharge of pus into the joint
Emphysematous osteomyelitis def, etiology
rare, intraosseous gas in the extra axial skeleton (pelvis, sacrum, lower extremity bones vertebrae)
Usually with hematogenous spread with comorbidities
Can be mono or poly microbial
Etiology: Enterobacteriaceae, fusobacterium necrophorum
is surgical debridement always needed for osteomyelitis
no, only if you have decubitus ulcers/wounds with compromised vasculature
In this case you can take bone sample at the same time as debridement
Are sinus tract cultures a good idea
no, results often dont correlate with pathogen in bone
histopathology of osteomyelitis shows
necrotic bone with resorption adjacent to an inflammatory exudate
