Septic Joints

A couple of cases on the wards currently of septic prosthetic joints – one patient with an infected hip and one patient with an infected knee.  Monoarticular arthritis has a different differential diagnosis than migratory arthritis.  Diagnosis of a septic joint is difficult to make based on symptoms and physical exam (see the JAMA article here), but can be made based on synovial fluid analysis +/- CRP & ESR, which can have predictive value in determining how to manage the patient.  The most common infectious agent is Staph aureus, but coag-negative Staph, Strep, N. gonorrhea and gram negatives are also possibilities. A nice review of septic prosthetic joint management can be found here with a decision chart on what kind of surgery to pursue.

Monoarticular arthritis: infection, gout, hemarthrosis, SLE, RA, tumor, OA

Migratory arthritis: gonococcal infection, lyme, SLE, gout, viral hepatitis