August 30, 2023

REBEL Core Cast 107.0 – Vertebral Osteomyelitis

7 minutes

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.

REBEL Core Cast 107.0 – Vertebral Osteomyelitis

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Definition

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.

Epidemiology

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.

Pathogenesis

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

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

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

Diagnosis

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

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 of 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

Management

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)

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

Graphics

Image 1: http://www.mghradrounds.org/clientuploads/nov_dec_2006/figure2.jpg

Image 2: http://www.thelancet.com/cms/attachment/2000991969/2003662063/gr3.jpg

References

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

Chowdhury V, Gupta A, Khandelwal N. Diagnostic Radiology: Musculoskeletal and Breast Imaging. 3rd ed. New Delhi: JP Brothers Medical Ltd; 2012

Della-Guistina, D. Evaluation and Treatment of Acute Back Pain in the Emergency Department. Orthopedic Emergencies 2015 May; 33(2) 311-26. PMID: 25892724

Gouliouris T, et al. Spondylodiscitis: update on diagnosis and management. J Antimicrob Chemother. 2010 Nov;65 Suppl 3:iii 11-24 PMID: 20876624

Mylona E, et al. Pyogenic Vertebral Osteomyelitis: A Systematic Review of Clinical Characteristics. Semin Arthritis Rheum. 2009 Aug; 39(1):10-7. PMID: 18550153

Pruitt CR, Perron AD. Specific Disorders of the Spine. In: Sherman SC eds. Simon’s Emergency Orthopedics. 7th ed. New York, NY: McGraw-Hill; 2014

Winters ME, Kluetz P et al. Back Pain Emergencies. Med Clin North Am, 2006 May;90(3):505-23. PMID: 16473102

Zimmerli W. Vertebral Osteomyelitis. N Engl J Med 2010 Mar; 362(11)1022-9. PMID: 20237348

Post Created By: Anand Swaminathan MD, MPH (Twitter @EMSwami)

Post Peer Reviewed By: Salim Rezaie MD (Twitter @SRRezaie)

The post REBEL Core Cast 107.0 – Vertebral Osteomyelitis appeared first on REBEL EM - Emergency Medicine Blog.

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