MRI Images - Vertebral Osteomyelitis (The Lancet)

MRI Images – Vertebral Osteomyelitis (The Lancet)


  • Inflammation of the vertebrae due to a pyogenic, fungal or mycobacterial organism.
  • Classified as either acute (days), subacute (weeks) or chronic (months)
  • Spondylodiscitis: a term encompassing osteomyelitis, spondylitis and discitis. Often used interchangeably with osteomyelitis.


  • 1 to 2.4 cases per 100,000 people (Zimmerli 2010)
  • More common in males with M:F of 3:1
  • Rate is also increasing due to increased number of spinal procedures
  • Typically affects adults, with most cases occurring in patients over 50 years old.


  • Infection occurs by three routes:
    • Hematogenous spread – secondary to infections of the GU, skin, soft tissue and respiratory system, indwelling catheters or endocarditis
      • Due to the bifurcated structure of the arterial supply, generally presents as infection of 2 contiguous vertebrae and the intervertebral disc
    • Direct inoculation during trauma or spinal surgery
    • Spread from adjacent soft tissue infection
  • Organism
    • Most cases in the United States are pyogenic.
      • Most common organism is Staph Aureus (36-67% of cases) (Boody 2015).
      • Other pathogens include: E. Coli, Pseudomonas Aeruginosa and Group B and G hemolytic Strep
    • Other pathogens to consider:
      • Fungal – blastomycosis, coccidiomycosis, histoplasmosis, aspergillosis
      • Brucellosis
      • Mycobacterial
    • Location: lumbar (48%) most common, followed by thoracic (35%) and cervical (6.5%)

History and Physical

  • Risk Factors:
    • Diabetes Mellitus (most common)
    • Immunosuppression: HIV, Malignancy, chronic steroids or immunosuppressant medication use
    • Spinal fracture, trauma or recent procedure
    • Substance Abuse: Alcoholism and IVDU
    • Presence of an indwelling vascular device
    • Elderly
  •  Symptoms
    • Back pain – often described as dull, may be present for weeks to months
    • Neurologic symptoms (paresthesias, weakness or radiculopathy) present in approximately one-third of patients
    • Most patients lack systemic symptoms
  • Exam
    • Tenderness over affected vertebrae
    • Paraspinal tenderness or spams may be present which may mislead the clinician towards a musculoskeletal diagnoses


  • Labs
    • Leukocytosis and Neutrophilia are poorly sensitive and highly non-specific (Gouliouris 2010). The degree of elevation does not predict disease severity.
    • ESR and CRP are sensitive, yet not specific.
      • CRP concentration rise and fall quicker than ESR, often used to guide treatment
    • Blood Cultures – an important element in management and treatment
      • Blood culture positivity often decides whether a patient will require a bone biopsy.
      • Cultured specimen narrows antibiotic coverage
    • Urinalysis/Urine Culture –UTI is a frequent missed source of bacteremia (especially in diabetic patients).
  • Imaging
    MRI Images (

    MRI Images –

    • Gadolinium enhanced MRI – modality of choice, highly sensitive and specific (Mylona 2009).
      • Although MRI with and without contrast is preferred, a non-contrast MRI can evaluate for inflammatory processes.
      • If a patient requires premedication or has renal failure, obtain the non-contrast MRI first. A contrast MRI can be done later to delineate subtle findings.
      • Findings include: enhancement (hypointense on T1 and hyperintense on T2) of vertebral endplates and adjacent disc space (Image 1)
    • CT Scan with IV contrast – use only if MRI contraindicated
      • Inferior in evaluation of disc spaces and neural tissues
        • Less sensitive than MRI and may be falsely negative in early disease
        • Used primarily by surgeons for biopsy of spine
      • Findings include loss of end plate definition and narrowing of disc space (Image 2)
      • Previously used CT Myelogram now out of favor due to potential for intradural spread of infection.
    • Plain Radiographs – often done to evaluate other causes (masses, fracture) however not recommended for diagnosis
      • Poorly sensitive and findings typically present in advanced disease (10-14 days after onset), once significant bone demineralization has already occurred
    • Radionuclide studies – (including: Tech 99m Bone scan, Gallium -67)
    • Sensitive but not specific, long acquisition time and difficult to obtain in the emergent setting


  • Pathogen directed therapy – Antibiotics tailored towards cultured organism
    • Given the dependence on blood culture results to guide therapy, current recommendations (IDSA 2015 Guidelines) suggest holding empiric antibiotics in medically stable patients (non-septic, hemodynamically stable, neurologically intact) until cultures grow out.
      • Note: this is a weak recommendation based on low quality evidence and patients should be managed on a case by case basis in conjunction with the inpatient treatment team
    • Empiric coverage:
      • Vancomycin 15-20 mg/kg/dose every 8-12 hrs PLUS
      • 3rd Generation Cephalosporin: Cefotaxime (2 g IV every 6 hrs), Ceftriaxone (1 to 2 g IV daily) or Ceftazidime (1 to 2 g IV every 8 -12 hrs)
      • Alternate: Cefepime 2 g IV every 12 hours
      • Duration: 6 weeks (occasionally 12 weeks if advanced disease) of IV antibiotics followed by 1-2 months of oral antibiotics
  • Surgical Consult – although most patients are successfully treated with antibiotics alone, some may require surgical intervention if there is concern for vertebral instability or spinal cord compromise.
    • Indications for surgical intervention include: associated abscess formation, spinal cord compression, progression of disease despite antimicrobial treatment
    • Obtain consult (Neurosurgery or Orthopedics) early, since patients may require bone biopsy for detection of organism

Take Home Points

  • Clinical presentation is very nonspecific; evaluate all patients presenting with back pain for infectious risk factors.
  • Baseline labs should not guide diagnosis, but may assist in later management.
  • MRI is key to diagnosis, obtain this imaging in all patients who raise clinical suspicion
  • Patients with hemodynamic instability and neurologic compromise warrant empiric antibiotics. The initiation of empiric antibiotics in hemodynamically stable, neurologically intact patients should be done on a case-by-case basis.


Berbari EF, Kanj SS, et al. Executive Summary: 2015 Infectious Disease Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adults. Clin Infect Dis 2015 Sept 15;61(6):859-63. PMID: 26316526

Boody B, et al. Vertebral Osteomyelitis and Spinal Epidural Abscess: An Evidence-based Review. J Spinal Disord Tech. 2015 Jul;28(6):E316-27 PMID: 26079841

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