11- OSTEOMYELITIS

• Osteomyelitis


  Infection involving bone
• Classification of osteomyelitis


  • Mechanism of infection (hematogenous vs nonhematogenous)
  • Duration (acute vs chronic)
• Hematogenous osteomyelitis


  Microorganisms enter the bone from bacteremia
• Nonhematogenous osteomyelitis


  Contiguous spread of infection to bone from adjacent soft tissues and joints or via direct inoculation of infection into the bone (trauma/wounds/surgery)
• Causative organisms


  • Staph aureus (most common)
  • Hemophilus influenzae
  • Salmonella (in sickle cell anemia)
• Risk factors


  • Recent trauma/surgery
  • Immunocompromised, DM, IV drug use
  • Poor vascular supply, peripheral neuropathy
• Presentation


  • New or worsening musculoskeletal pain and fever
  • Erythema, tenderness, edema, impaired weight bearing
  • If chronic, may have abscess or draining sinus tract
• Acute osteomyelitis is a medical emergency which requires an early diagnosis and appropriate antimicrobial and surgical treatment
• Investigations


  • WBC/differentials, ESR, CRP, blood culture, aspirate culture/bone biopsy
  • MRI is the imaging modality of choice (CT and bone scan may also be used)
  • Plain film changes are visible after 8-10 days (soft tissue swelling, periosteal reaction, pockets of air, "moth-eaten" appearance, endosteal scalloping, cortical destruction, peripheral sclerosis [late sign])
• Acute osteomyelitis treatment


  1. IV antibiotics for 4-6 weeks; started empirically and adjusted after obtaining blood and aspirate cultures

  2. Surgery (I&D) for abscess or significant involvement

  3. Hardware removal (if present)
• Chronic osteomyelitis treatment


  1. Surgical debridement

  2. Antibiotics (both local ex: antibiotic beads and systemic IV)