Infection Flashcards
Term for bone infection vs joint vs disc infection
Osteomyelitis (bone)
Septic arthritis (joint)
Spondylodiscitis (disc)
Highest age incidence for infection?
2-12 years (immature immune system, more exposure to organisms)
Most common bones to be infected?
Femur (m/c) >tibia > humerus >radius (excluding diabetic foot which is crazy common)
Delay in radiographic findings from the initiation of infection? (appendicular & spine)
7-10 days in the appendicular skeleton
21 days in the spine
Do children or adults present with more acute symptoms of infection, typically?
Children
Most common organism for MSK infection?
Staph Aureus (90%)
Symptoms of infantile infection?
infant unwilling to move affected bone due to pain, may find swelling in the region of infection, may be multi-focal
Most common route of spread for osteomyelitis?
Hematogenous
Osteomyelitis is often indistinguishable on x-ray from…
Malignant bone lesions
A piece of necrotic bone separated from living bone
Sequestrum
A thick layer of enveloping periosteal new bone around an infection
Involucrum
opening through involucrum/cortex into the marrow from the soft tissue
Cloaca
Infection from bone weeping out of the skin surface
Sinus tract
Radiographic features of spondylodiscitis?
Early/rapid loss of disc height, ENDPLATE DESTRUCTION
In children age 1-16, osteomyelitis tends to localize where?
Metaphysis
Due to slow blood flow in metaphyseal capillary beds and low pH and oxygen tension
Chronic/subacute form of localized osteomyelitis, may look loke a benign tumor
Brodie Abscess
Radiographic features of a Brodie abscess?
Lucent lesion, poorly OR well defined, a lot of surrounding sclerosis (the surrounding sclerosis is what makes it a Brodie abscess and not just regular osteomyelitis)
May be mistaken radiographically and clinically for an osteoid osteoma?
Cortical Brodie abscess
MC location for a Brodie abscess?
Tibia
Which would be best to identify a sequestrum, CT or MRI?
CT
Osteomyelitis complications?
Pathologic fractures
Growth disturbances (children)
Ankylosis (septic arthritis)
Malignant degeneration (squamous cell MC)
Septicemia
Monoarticular inflammatory arthritis
Infection (septic arthritis) until proven otherwise
MC sites for septic arthritis?
Hip & knee, diabetic foot
What is Waldenström’s sign?
Increase medial hip joint space (11mm total, 2mm difference side to side)
Indicates intraarticular swelling in the hip of children
