Osteomyelitis Guidelines

Updated: Mar 01, 2018
  • Author: Stephen Kishner, MD, MHA; Chief Editor: Murali Poduval, MBBS, MS, DNB  more...
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Guidelines

ACR Criteria for Suspected Osteomyelitis, Septic Arthritis, or Soft-Tissue Infection (Excluding Spine and Diabetic Foot)

The American College of Radiology (ACR) has published clinical practice guidelines for the diagnosis of suspected musculoskeletal infections (with the spine and diabetic foot excluded). [21] These recommendations are summarized below.

First study in suspected osteomyelitis, septic arthritis, or soft-tissue infection (excluding the spine and diabetic foot):

  • The initial study should be a radiograph

Additional imaging after radiography with soft-tissue or juxta-articular swelling and suspected soft-tissue infections:

  • Magnetic resonance imaging (MRI) is favored over computed tomography (CT) to determine the extent of soft-tissue infection
  • MRI with and without intravenous (IV) contrast is preferred, but MRI without IV contrast is an alternative if contrast is contraindicated
  • Ultrasonography (US) has decreased visualization of deep structures but may be more useful in young children or in cases of foreign bodies, joint effusions, or soft-tissue fluid collections

Soft-tissue or juxta-articular swelling with a history of puncture wound with suspected foreign body and negative radiographs:

  • US is recommended for visualization of radiolucent foreign bodies
  • CT without IV contrast is preferred for radiopaque foreign bodies

Additional imaging after radiography in soft-tissue or juxta-articular swelling and a skin lesion, injury, wound, ulcer, or blister in suspected osteomyelitis:

  • MRI with and without IV contrast is preferred in cases of acute osteomyelitis
  • MRI without IV contrast is an alternative if contrast is contraindicated
  • CT with IV contrast may be used if MRI is contraindicated
  • A labeled leukocyte scan with technetium-99m ( 99mTc) three-phase bone scan or 99mTc sulfur colloid has greater specificity in infections

Additional imaging after radiography in soft-tissue swelling or juxta-articular swelling with a history of prior surgery:

  • If septic arthritis is suspected, aspiration of the area is recommended
  • MRI with and without IV contrast is also recommended to evaluate for osteomyelitis and to determine the degree of infection; MRI without IV contrast is appropriate if contrast is contraindicated; CT with IV contrast is appropriate if MRI is contraindicated

Additional imaging after radiography in pain and swelling or cellulitis associated with a site of previous nonarthroplasty hardware and suspected osteomyelitis or septic arthritis:

  • If septic arthritis is suspected, aspiration of the area is recommended
  • MRI with and without IV contrast is also recommended to evaluate for osteomyelitis and to determine the degree of infection; MRI without IV contrast is appropriate if contrast is contraindicated; CT with IV contrast is appropriate if MRI is contraindicated
  • A labeled leukocyte scan with  99mTc sulfur colloid marrow scan has greater specificity for infection and is usually appropriate, especially if extensive hardware is present

Additional imaging after radiography in draining sinus (not associated with a joint prosthesis) in suspected osteomyelitis:

  • MRI with and without IV contrast is recommended; MRI without IV contrast is appropriate if contrast is contraindicated; CT with IV contrast is appropriate if MRI is contraindicated

First study in the clinical examination suggesting crepitus and suspected soft-tissue gas:

  • Radiographs are recommended as the initial study, but they are less able to detect deep fascial gas
  • CT with IV contrast, if not contraindicated, has the highest sensitivity in detecting soft-tissue gas

Initial radiographs showing soft-tissue gas in the absence of a puncture wound:

  • CT without IV contrast is recommended as the initial study because it has a high sensitivity for detecting soft-tissue gas and can be completed quickly
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IDSA Guidelines for Native Vertebral Osteomyelitis in Adults

The Infectious Diseases Society of America (IDSA) has published clinical practice guidelines for the diagnosis and treatment of native vertebral osteomyelitis (NVO) in adults, including recommendations regarding antibiotic therapy and surgical intervention. [36]  These recommendations are structured on the basis of answers to 13 clinical questions, as follows.

Clinical diagnostics

When should the diagnosis of NVO be considered?

  • In patients with new or worsening back or neck pain and fever
  • In patients with new or worsening back or neck pain and elevated erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP)
  • In patients with new or worsening back or neck pain and bloodstream infection (BSI) or infective endocarditis
  • Potentially, in patients who present with fever and new neurologic symptoms with or without back pain
  • Potentially, in patients who present with new localized neck or back pain, following a recent episode of Staphylococcus aureus bloodstream infection

What is the appropriate diagnostic evaluation for suspected NVO?

  • Recommended: a pertinent medical and motor/sensory neurologic examination in patients with suspected NVO
  • Recommended: bacterial (aerobic and anaerobic) blood cultures (two sets) and baseline ESR and CRP in all patients with suspected NVO
  • Recommended: MRI of the spine in patients with suspected NVO
  • Suggested: a combination spine gallium/ 99mTc bone scan or CT or positron emission tomography (PET) in patients with suspected NVO when MRI cannot be obtained (eg, implantable cardiac devices, cochlear implants, claustrophobia, or unavailability)
  • Recommended: blood cultures and serologic tests for Brucella sp. in patients with subacute NVO residing in endemic areas for brucellosis
  • Suggested: fungal blood cultures in patients with suspected NVO and at risk for fungal infection (epidemiologic risk or host risk factors)
  • Suggested: purified protein derivative (PPD) test or obtaining an interferon gamma release assay in patients with subacute NVO and at risk for Mycobacterium tuberculosis NVO (ie, originating or residing in endemic regions or having risk factors)
  • May be considered: in patients with suspected NVO, evaluation by an infectious disease specialist and a spine surgeon

When should an image-guided aspiration biopsy or additional workup be performed?

  • Recommended: image-guided aspiration biopsy in patients with suspected NVO (on the basis of clinical, laboratory, and imaging studies) when a microbiologic diagnosis for a known associated organism ( S aureus, Staphylococcus lugdunensis, and Brucella sp.) has not been established by blood cultures or serologic tests
  • Not advised: image-guided aspiration biopsy in patients with S aureus, S lugdunensis, or Brucella sp. BSI suspected of having NVO on the basis of clinical, laboratory, and imaging studies
  • Not advised: image-guided aspiration biopsy in patients with suspected subacute NVO (high endemic setting) and strongly positive Brucella serology (strong, low).

How long should antimicrobial therapy be withheld before image-guided diagnostic aspiration biopsy in suspected NVO?

  • Recommended: immediate surgical intervention and initiation of empiric antimicrobial therapy in patients with neurologic compromise with or without impending sepsis or hemodynamic instability

When is it appropriate to send fungal/mycobacterial/brucellar cultures or other specialized testing after image-guided aspiration biopsy in suspected NVO?

  • Suggested: addition of fungal, mycobacterial, or brucellar cultures on image-guided biopsy and aspiration specimens in patients with suspected NVO if epidemiologic, host risk factors, or characteristic radiologic clues are present
  • Suggested: addition of fungal and mycobacterial cultures and bacterial nucleic acid amplification testing (NAAT) to appropriately stored specimens if aerobic and anaerobic bacterial cultures reveal no growth in patients with suspected NVO

When is it appropriate to send specimens for pathologic examination after image-guided aspiration biopsy in suspected NVO?

  • Recommended: from all patients (if adequate tissue can be safely obtained) to help confirm NVO and guide further diagnostic testing, especially in the setting of negative cultures

What is the preferred next step with nondiagnostic image-guided aspiration biopsy and suspected NVO?

  • Recommended: in the absence of concomitant BSI, a second aspiration biopsy if the original image-guided aspiration biopsy specimen grew a skin contaminant (coagulase-negative staphylococci [except S lugdunensis], Propionibacterium sp., or diphtheroids)
  • Recommended: with a nondiagnostic first image-guided aspiration biopsy and suspected NVO, further testing to exclude difficult-to-grow organisms (eg, anaerobes, fungi, Brucella sp., or mycobacteria)
  • Suggested: with suspected NVO and a nondiagnostic image-guided aspiration biopsy and laboratory workup, either repeating a second image-guided aspiration biopsy, performing percutaneous endoscopic diskectomy and drainage (PEDD), or proceeding with an open excisional biopsy

Clinical therapy

When should empiric antimicrobial therapy be started?

  • Suggested: in patients with normal and stable neurologic examination and stable hemodynamics, hold empiric antimicrobial therapy until a microbiologic diagnosis is established
  • Suggested: in patients with hemodynamic instability, sepsis, septic shock, or severe or progressive neurologic symptoms, initiate empiric antimicrobial therapy in conjunction with an attempt at establishing a microbiologic diagnosis

What is the optimal duration of antimicrobial therapy?

  • Recommended: total duration of 6 weeks of parenteral or highly bioavailable oral antimicrobial therapy for most patients with bacterial NVO
  • Recommended: total duration of 3 months of antimicrobial therapy for most patients with NVO due to Brucella sp.

What are the indications for surgical intervention?

  • Recommended: surgical intervention in patients with progressive neurologic deficits, progressive deformity, and spinal instability with or without pain despite adequate antimicrobial therapy
  • Suggested: surgical debridement with or without stabilization in patients with persistent or recurrent BSI (without an alternative source) or worsening pain despite appropriate medical therapy
  • Not advised: surgical debridement and/or stabilization in patients who have worsening bony imaging findings at 4-6 weeks in the setting of improvement in clinical symptoms, physical examination, and inflammatory markers

Clinical follow-up

How should failure of therapy be defined in treated patients?

  • Suggested: persistent pain, residual neurologic deficits, elevated markers of systemic inflammation, or radiographic findings alone do not necessarily signify treatment failure in treated patients 

What roles do systemic inflammatory markers and MRI play in follow-up after treatment?

  • Suggested: monitoring ESR, CRP, or both after approximately 4 weeks of antimicrobial therapy, in conjunction with a clinical assessment
  • Not recommended: routinely ordering a follow-up MRI in patients who exhibit a favorable clinical and laboratory response to antimicrobial therapy
  • Suggested: performing a follow-up MRI to assess evolutionary changes of the epidural and paraspinal soft tissues in patients who are judged to have a poor clinical response to therapy

How should suspected treatment failure be approached?

  • Suggested: obtaining ESR and CRP values; unchanged or increasing values after 4 weeks of treatment should increase suspicion for treatment failure
  • Recommended: obtaining a follow-up MRI with emphasis on evolutionary changes in the paraspinal and epidural soft-tissue findings
  • Suggested: in patients with clinical and radiographic evidence of treatment failure, obtaining additional tissue samples for microbiologic (bacteria, fungal, and mycobacterial) and histopathologic examination, either by image-guided aspiration biopsy or through surgical sampling
  • Suggested: in patients with clinical and radiographic evidence of treatment failure, consultation with a spine surgeon and an infectious disease physician
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