Septic Arthritis

Septic Arthritis

• ACUTE monoarticular arthritis is septic arthritis until proven otherwise. 
• Requires URGENT medical management, ANTIBIOTICS ARE NOT ENOUGH. 
• Investigations
  • Infection Picture (elevated WBCs, fever, soft BP)
• Joint Aspiration
  • MUST BE PERFORMED to rule out infection
  • Send for (3 C's)
    • Cells (Count and Diff):
      • Inflammation > 2000/mm^3
      • Neutrophils >90% consistent with infection
      • Typically Infections Arthritis will have WBCs > 50,000
    • Crystals
      • Seeing rhomboid positive birefringent crystals (CPPD) is common, still rule out infection. (infection releases CPPD from cartilage)
    • Culture & Gram Stain
      • Gram Stain does not rule out infection (only positive 20% of septic arthritis), must cover with broad abx and await culture. 
• Organisms:
  • MRSA & S. aureus
  • Klebsiella pneumoniae
  • Neisseria gonorrhoeae
• Management:
  • Causes irreversible joint damage
  • Antibiotics (but not enough)
    • First Line: Vancomycin & Ceftriaxone
    • Vancomycin for MRSA, Ceftraixone for Gram +'s and Gram -'s (including N.gonorrhea)
  • Isolation of organism. 
  • Find the source (hematologic spread from somewhere like IVDU)
  • Frequent joint aspirations
  • Surgical consult
    • Possibility of surgical management
    • May need irrigation & debridement