Artritis séptica

What is Useful in the ED to Help Diagnose or Rule Out Septic Arthritis?

Taming The SRU - October 5, 2015

HISTORY
There are many risk factors for septic arthritis including age >80, Diabetes, Rheumatoid Arthritis, recent joint surgery, prosthesis, cellulitis. The absence of risk factors does not make septic arthritis less likely in an acute monoarticular arthritis
PHYSICAL
Monoarticular arthritis is often characterized as a warm, painful, swollen joint with limited range of motion. No studies to date have quantified specificity data on the physical exam. Therefore, clinicians must use their own clinical gestalt when interpreting physical exam findings.
SERUM TESTS
Useless – unless ESR and CRP are negative. In this case, low negative likelihood ratios may help to exclude septic arthritis
SYNOVIAL FLUID ANALYSIS

• sWBC > 50,000 - essentially rules IN septic arthritis
• sWBC < 50,000 - unhelpful for clinical diagnosis
• Gram Stain: useful when positive, unhelpful when negative
• Culture: not available when we need it in the ED
• Lactate >10 - essentially rules IN septic arthritis

In the end, clinicians must determine their own pre-test probabilities and interpret history, physical exam, and labs as a whole picture. When in doubt, it is safest to treat the patient with antibiotics and consult Orthopaedic Surgery for further management.
For more detailed information check out this article by Margaretten, et al (2007) - "Does This Adult Patient Have Septic Arthritis"

http://www.tamingthesru.com/blog/grand-rounds/septic-arthritis