Osteomyelitis

From WikEM
Jump to: navigation, search

Background

  • Infection of the bone by bacteria or fungus
  • Etiology
    • Contiguous spread (80%)
    • Hematogenous spread (20%)
      • More common in pediatric (long bones)
      • Less common in adults (spine)

Risk Factors

  • Diabetic patients with one or more of the following:
    • Skin ulceration >2cm
    • Positive probe-to-bone test
    • ESR >70 (83-92% Sn)
    • Abnormal x-ray

Clinical Features

  • Pain at the site
    • May also have warmth, swelling, erythema

Differential Diagnosis

Skin and Soft Tissue Infection

Look-A-Likes

Evaluation

  • X-ray
    • May be normal early in the course
    • Later will show bone demineralization, periosteal elevation, lytic lesions
    • Changes 10-21 days after infection
    • Sn 43-75%, Sp 75-83%[1]
  • Blood culture
  • CT
    • Sn 67%, Sp 50%[2]
  • MRI is the standard for diagnosis (as early as 3-5 days after infection)[3]
  • Bone scan is sensitive, but lacks specificity vs. MRI

Management

Risk Factor Likely Organism Initial Empiric Antibiotic Therapy'
Elderly, hematogenous spread MRSA, MSSA, gram neg Vancomycin 1gm + (Piperacillin/Tazobactam 3.375 grams OR imipenem 500mg)
Sickle Cell Disease Salmonella, gram-negative bacteria Ceftriaxone 50mg/kg IV once daily OR Cefotaxime 50mg/kg IV three times daily, PLUS
  • Vancomycin 15mg/kg IV four times daily OR
  • Clindamycin 10mg/kg IV PO four times daily OR
  • Nafcillin 50 mg/kg IV four times daily to cover K. Kingae (common in daycare population)
DM or vascular insufficiency Polymicrobial: Staph, strep, coliforms, anaerobes Vancomycin 1gm + (Piperacillin/Tazobactam 3.375 grams OR imipenem 500mg)
IV drug user MRSA, MSSA, pseudomonas Vancomycin 1gm 
Newborn MRSA, MSSA, GBS, Gram Negative Vancomycin 15mg/kg load, then reduce dose, AND ceftazidime 30mg/kg IV q12 h
Children MRSA, MSSA Vancomycin 10mg/kg q6 h AND ceftazidime 50mg/kg q8hr
Postoperative (ortho) MRSA, MSSA Vancomycin 1gm
Human bite Strep, anaerobes, HACEK organism Piperacillin/Tazobactam 3.375gm OR imipenem 500mg
Animal bite Pasteurella, Eikenella, HACEK organism Piperacillin/Tazobactam 3.375gm OR imipenem 500mg

See Also

References

  1. Pineda et al. Semin Plast Surg 2009;23:80–89.
  2. Pineda et al. Infect Dis Clin N Am. 2006, 20: 789–825
  3. Pineda C et al. Radiographic Imaging in Osteomyelitis: The Role of Plain Radiography, Computed Tomography, Ultrasonography, Magnetic Resonance Imaging, and Scintigraphy. Semin Plast Surg. 2009 May; 23(2): 80–89.