10- SEPTIC ARTHRITIS

• Medical emergency


  Usually monomicrobial, most commonly by Staph. Aureus; may also be caused by streptococci. May be caused by gram -ve organisms in elderly, IV drug users, or immunocompromised patients
• How it arises


  1. Most commonly via hematogenous seeding

  2. May also develop from direct inoculation of bacteria into the joint

  3. Rarely develops via extension of infection into joint space from adjacent tissues
• Risk factors


  • Prosthetic joint
  • Previous joint disease
  • Recent intraarticular steroid injection
  • Diabetes
• Clinical presentation


  • Usually present acutely with a single swollen and painful joint (monoarticular)
  • Joint pain, swelling, erythema, warmth, and restricted movement
  • Hot, painful, swollen, red joint, very limited ROM
  • Fever, evidence of infection (older patients may be afebrile)
  • 20% of patients may present with oligoarticular or polyarticular infection
• Joints most commonly involved


  • Knee (50% of cases)
  • Wrists
  • Ankles
  • Hips
• Differential diagnoses


  • Crystal-induced arthritis (gout or pseudogout)
  • Reactive arthritis
  • Septic bursitis
  • Acute traumatic arthritis
• Synovial Fluid Aspiration


  Investigations
• Blood tests


  • CBC
  • ESR
  • CRP
  • Blood culture
• 1. ray has no value
• Treatment of Acute Septic Arthritis


  1. IV flucloxacillin (penicillin) + vancomycin in immunocompromised

  2. Modify antibiotics depending on culture and sensitivity

  3. Continue 2 weeks of IV antibiotics followed by 2 weeks of oral antibiotics

  4. Adequate drainage by aspiration, arthroscopy, or open drainage

  5. NSAIDs for pain

  6. Immobilize acutely but mobilize early to avoid contractures
• Prosthetic joint à always ortho. Don't insert needle
• Gonococcal Septic Arthritis


  • After asymptomatic genital/rectal local infection
  • Young adults
  • Maculopapular pustules
  • Culture positive in blood, joint, and genital fluid
• Treatment of Gonococcal Septic Arthritis


  2 weeks: penicillin, ciprofloxacin, or doxycycline
• Meningococcal Septic Arthritis


  • Migratory polyarthritis
  • Deposition of circulatory immune complexes with meningococcal antigens
• Treatment of Meningococcal Septic Arthritis

  Penicillin
• Tuberculous Septic Arthritis


  • Hip, knee, spine
  • Febrile, night sweats, weight loss
  • Insidious onset, pain, swelling, dysfunction
• Treatment of Tuberculous Septic Arthritis

  Tb treatment for 9 months
• Culture or biopsy necessary for Tuberculous Septic Arthritis
• Synovial Fluid Characteristics


  • WBC 0-200, PMN <10%, Straw, Normal
  • WBC 200-2000, PMN <20%, Straw, Non-inflammatory (osteoarthritis)
  • WBC 2000-50000, PMN 20-75%, Cloudy, Inflammatory
  • WBC >50000, PMN >75%, Opaque, Pyarthrosis (septic)
• Urgent gram stain & polarized light microscopy for crystals