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MSS Weeks 3-5 > Bone Infections > Flashcards

Flashcards in Bone Infections Deck (10)
1

Categories of osteomyelitis

Hematogenous - Result from seeding of a bone related to a previous bacteremia
Direct implantation - Resulting from penetrating injury
Contiguous - Resulting from direct spread of bacteria from an overlying wound or pressure ulcer
Infection of Prosthetic Device - Resulting from infection of prosthetic material implanted in bone, with spread of organisms into the adjacent bone

2

Commonality of osteomyelitis categoreis by age

Children - Hematogenous more common
Adults - Contigious and prosthetic infections

3

Pathogens by category

  • Hematogenous - Staph aureus, Strepto sp., gram-negatives, M. tuberculosis, Salmonella sp. (sickle-cell)
  • Direct implantation - Pseudomonas aeruginosa (nail inj. with sneakers)
  • Contiguous - S. aureus, gram-negatives, Strepto sp., anaerobes, Candida sp.
  • Prosthetic Joint Infections - Coagulase negative staph, S. aureus, gram-negatives, Strep sp.

4

What is the duration of osteomyelitis infections?

Chronic infections

5

Define the following:
Sequestrum
Involocrum
Brodie's abscesses

  • Sequestrum - Dead bone
  • Involucrum - External bone formation
  • Brodie's absecces - Localized abscesses

6

Diagnostics for osteomyelitis

X-rays may be negative in early infection, and in fact are not very sensitive for osteomyelitis
Bone/WBC scans or MRI imaging more effective
Bone biopsies or sometimes blood cultures for bacteri

7

Issues with culturing for osteomyelitis

Cultures of open ulcers overlying contigous osteomyelitis are unreliable
Sometimes biopsies cannot be done or the culture results may be negative, forcing empiric treatment

8

Difficulty of prosthetic osteomyelitis

Particularly difficult to treat, especially due to chance of biofilm generation
Prosthesis often needs to be removed for treatment to eradicate infection

9

What are biofilms?
What is special about their arrangement?
How do they compare to planktonic (suspended) organisms?

  • Aggregations of microoranisms adhrent to a surface (e.g. bone or prosthetic)
  • Embedded in a matrix they produce - slime or extracellular polymeric substance or glycocalyx
  • Differences in biochemistry and physiology of biofilm organsm and more resistant to antibiotics

10

Hematogenous Osteomyelitis

Resulting from seeding of bone related to a previous bacteremia.