17 Nov Septic Arthritis

Long break from posting for a thousand reasons - but wanted to add some info from today's discussion on septic arthritis.  The case was a pt with previous history of total knee arthroplasty (bilateral) and diabetes mellitus.  He as admitted with fevers with swelling and tenderness of his knee.  Arthrocentesis revealed bloody synovial fluid with ~ 50 000 leukocytes.  Only 50% or so were polys.  Cultures of blood and synovial fluid were both noted to be positive for group G streptococcus.

Acute monoarthritis must be evaluated rapidly.  Arthrocentesis is quick, easy, and safe and is the key to differentiating septic arthritis from other causes of monoarthritis.  Do not rely on elevated uric acid levels in serum analysis to make a diagnosis of gout.  Gout and septic arthritis can and often do coexist.  Hematogenous infections of prosthetic joints usually result in loss of the joint.  In some cases of acute postoperative prosthetic joint infection the prosthesis can be salvaged with joint washout and prolonged (6 months) antibiotic therapy.

Linked here is the seminal article from NEJM on the approach to monoarthritis.  Still the ideal approach to this situation.

Also - diabetes mellitus is a significant risk factor for invasive streptococcal infections, and there seems to be an increasing indicence of Groups B, C, and G streptococcus.  These organisms are exquisitely susceptible to penicillin.