Osteomyelitis - Sohnle Flashcards
What are the 4 given categories (etiologies) of osteomyelitis?
Which is most common in children?
Hematogenous, direct implantation (eg puncture), contiguous (eg overlying infection), and via prosthetics.
Hematogenous is the most typical osteomyelitis in children.
Contrast the appearance of infected bone with healthy bone on X-ray.
Infected bone is less dense, often featuring a lytic center and sclerotic rim.
What bacterium is the most common culprit in direct implantation osteomyelitis?
Pseudomonas Aeruginosa
Why are prosthetic devices conducive to osteomyelitis?
How are these infections usually handled?
The prosthesis provides a good substate to form biofilms.
Treatment usually requires complete removal of the prosthetic.
What pathogens are found in hematogenous osteomyelitis?
Staph, Strep, gram-negatives, Tuberculosis, Salmonella (in sickle cell).
What pathogens are found in contiguous osteomyelitis?
Staph, Strep, gram-negatives, anaerobes, and Candida.
What pathogens are found in prosthetic joint infections?
Staph, strep, gram-negatives.
Describe some complications of osteomyelitis.
Infection may result in pieces of dead bone (sequestrum) or new external bone (involucrum). Brodie’s (local) abscesses may occur.
Describe the diagnostic protocol for identifying osteomyelitis.
Imaging: Bone/MRI scans are superior to X-rays.
Lab: WBC counts, bone/blood cultures.
What options are available if bone biopsies are unavailable?
Empiric treatment only. Do not rely on overlying wound cultures!
Describe the structure of a biofilm. Why are they significant?
What antibiotic seems especially potent in treating them?
Biofilms consist of microorganisms embedded in a self-produced matrix (“slime”/glycocalyx), which grants unique behaviors and resistance to antibiotics.
Rifampin (recall: binds bacterial RNA pol)
Describe a typical course of treatment of osteomyelitis.
6 weeks intravenous antibiotics, possibly with oral antibiotics and/or surgery to remove sequestra or prostheses.
Note: No point in antibiotics if bone is exposed.
define sequestrum
pieces of dead bone
define involcrum
new bone external bone formation
What is a name for a localized abscess in bone?
Brodie’s abscess
