II. Pathophysiology

  1. Necrotic bone is identified on presentation (contrast with inflammation in Acute Osteomyelitis)
  2. Often polymicrobial infection (contrast with Acute Osteomyelitis, which is often monomicrobial)

III. Findings: Symptoms and Signs

  1. Presentation may be delayed 6 weeks or more after symptom onset
  2. Fever is often absent
  3. Non-healing ulcers (necrotic tissue may be present within ulcer)
  4. Non-healing Fractures or wounds over surgical hardware or regions of Trauma
  5. Localized bone pain
  6. Erythema and swelling at affected area
  7. Draining sinus tracts
  8. Decreased range of motion of adjacent joints
  9. Diminished blood supply

IV. Types

  1. Open Fracture (27% Incidence of Osteomyelitis within 3 months)
  2. Contigiuous spread from soft tissue infection
    1. Associated with Diabetic Neuropathy and Peripheral Vascular Disease
  3. Hematogenous spread from bacteremia
    1. Much less common in adults than in children
    2. Vertebrae are most common locations for infection
      1. See Vertebral Osteomyelitis
      2. Presents with back pain
      3. Most common with IV Drug Abuse, Diabetes Mellitus, Chronic Kidney Disease, cancer
    3. Long bones, Pelvis and clavicle may also be affected

V. Causes

VI. Differential Diagnosis

VII. Labs

VIII. Imaging

IX. Diagnosis

  1. Imaging (XRay, bone scan, MRI) demonstrates contiguous soft tissue infection or bony destruction
  2. Signs suggestive of contiguous Wound Infection spread to bone
    1. Exposed bone
    2. Persistent sinus tract
    3. Tissue necrosis over bone
    4. Chronic Wound overlying Fracture
    5. Chronic Wound overlying surgicl hardware
  3. Labs suggestive of inflammation or infection (sensitive but not specific, more useful in children)
    1. Blood Cultures positive (Test Sensitivity less than 50%)
    2. C-Reactive Protein (C-RP) increased
    3. Erythrocyte Sedimentation Rate (ESR)
  4. References
    1. Hatzenbuehler (2011) Am Fam Physician 84(9): 1027-33 [PubMed]
    2. American Society of Plastic Surgery Guidelines
      1. http://www.guideline.gov/content.aspx?id=11513

X. Diagnosis: Most Predictive of Osteomyelitis

  1. Probe-to-Bone Test
  2. Skin Ulceration over a bony prominence
    1. Ulcer present over 2 weeks
    2. Ulcer over 2 cm in size
      1. Test Sensitivity: 56%
      2. Specificity: 92%
    3. Ulcer depth exceeds 3 mm

XI. Management

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