(3) Osteomyelitis, Spondylodiscitis, Brodie Abscess Flashcards
(47 cards)
What is osteomyelitis?
suppurative form of bone/marrow infection
What is the most common infectious organism of osteomyelitis?
staphylococcus aureus
What infectious organisms may cause osteomyelitis?
- staph aureus
- E. coli
- H. influenzae
- klebsiella
- streptococcus B
What infectious organisms may cause non-suppurative forms of osteomyelitis?
- TB
- syphilis
- coccidiodomycosis
What populations are predisposed to osteomyelitis?
- immunocompromised (corticosteroids, DMARDs, etc.)
- alcoholics
- newborns
- IV drug abusers
- diabetics (poor healing, ulcers)
- hemodialysis pts
- post-surgical
What are the 4 pathways of spread of osteomyelitis?
- hematogenous (MC)
- contiguous (adjacent) source
- direct implantation
- postoperative
What are the early imaging findings of osteomyelitis?
- soft tissue swelling
- aggressive bone destruction (permeative/motheaten, wide ZoT)
- aggressive periosteal Rxn (laminated, spiculated, codman)
- dark on T1 (replacement of marrow fat w/ bacteria, pus, hemorrhage)
What are the later imaging findings of osteomyelitis?
- sequestrum formation (may calcify)
- involucrum formation (periosteal Rxn)
- cloaca formation
- sinus tract
What is a cloaca?
an opening in the cortex of bone that allows bacteria to spread to other tissues
What is a sequestrum?
necrotic infected bone tissue
(area of permeative osteolysis, wide ZoT, may have calcification)
What is an involucrum?
an area of reactive bone formation that forms a sheath/wall around a sequestrum
What are some of the cardinal signs and symptoms of osteomyelitis?
- painful erythema & swelling/edema
- Rapid onset, high fever
- malaise
- ^ESR
- ^WBC
- pre-existing infection
When using the term “osteomyelitis” on its own, the implication is…
acute pyogenic osteomyelitis
What type of edema is produced by the tissue necrosis in osteomyelitis?
Purulent exudate
How long does it take for osteomyelitis to appear on x-ray in the extremities versus the spine?
- extremities: 7-10 days
- spine: 21 days
What is a sinus?
where pus drains from bone into the outside environment
If you see permeative destruction in the metaphysis of a kid, what is on your list of differentials?
- Osteomyelitis
- Osteosarc.
- Ewing sarc.
- lymphoma
If you see permeative destruction in the diaphysis of a kid, what is on your list of differentials?
- Osteomyelitis
- Ewing sarc.
- Osteosarc.
- lymphoma
What is spondylodiscitis?
acute suppurative infection of the spine (vertebrae and/or discs)
What follow-up is required to differentiate osteomyelitis from neoplasia?
MRI with contrast
What is the most common infectious organism of spondylodiscitis?
staph aureus
What is the radiographic latent period of spondylodiscitis?
3 weeks
What part of the spine is typically involved first in children with spondylodiscitis?
disc
What part of the spine is typically involved first in adults with spondylodiscitis?
ant. body endplate –> vertebral destruction & secondary disc involvement
(arterial pattern)