Where did all the staph go......

Differential for Acute Monoarthritis:

Infectious: SEPTIC UNTIL PROVEN OTHERWISE!!! (Gonococcal vs Non-gonococcal)
Crystal Arthropathy: Gout, Pseudogout (CPPD), Hydroxyapatite
Inflammatory
Seropositive arthritis (early RA or SLE)
Seronegative arthritis (psoriatic, Ankylosing spondilitis, IBD, reactive)
Degenerative: OA

Trauma:Hemarthrosis

Extra-articular: Bursitis, cellulites, ruptured Baker’s cyst, tendonitis, etc…

Check out this link to a recent CMAJ review with an approach to monoarthitis:
http://www.cmaj.ca/cgi/content/full/180/1/59

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On another note.....we also talked a little bit about osteomyelitis. On an x-ray you might se:

• Findings: Early
  Soft tissue swelling
  Periosteal reaction (Subperiosteal elevation)


• Findings: Later
  Osteolysis
  Sequestra (islands of necrotic bone)
  Bone abscess (Brodie's abscess)
  

Efficacy: Test sensitivity 62% (43-75% in DM Foot Osteo), Test Specificity 64% (65-83% in DM Foot Osteo)
Limitations: Bone changes lag infection by 10-20 days, XRay changes not seen until 40-70% bone resorbed

Going back to the clinical exam this article looks at predictive findings for osteomyelitis in diabetics while you wait for that MRI....

http://jama.ama-assn.org/cgi/content/full/299/7/806