Osteomyelitis

Diabetic Foot Ulcer, Vertebral Osteomyelitis

  • Diagnosis
  • Monitoring
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • Chronic, nonhealing ulcer that can be probed to the bone (eg, diabetic foot ulcer, decubitus ulcer in immobilized patient)
  • Localized bone pain with signs and/or symptoms of infection
  • Back pain or neck pain with
    • Fever
    • Elevated C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR)
    • Blood stream infection or infective endocarditis
    • Recent Staphylococcus aureus bacteremia
  • New neurological symptoms with or without back pain or neck pain

Laboratory Testing

  • CBC
    • May be normal or show leukocytosis or left shift
    • Leukocyte count may be normal in chronic or indolent osteomyelitis
    • Normocytic normochromic anemia may be present if infection is chronic (anemia of chronic inflammation)
  • CRP
    • Preferred test to detect acute inflammation (Choosing Wisely, American Society for Clinical Pathology, 2016)
    • Emerging as preferred marker for diagnosis and monitoring of osteomyelitis
    • Frequently elevated but not specific
    • Normal ESR and CRP essentially rule out osteomyelitis
    • Specific types
      • Vertebral osteomyelitis – use CRP in conjunction with ESR in all patients with clinical signs (IDSA, 2015)
      • Diabetic foot osteomyelitis – use CRP with ESR in conjunction with white blood cell (WBC) count to assess severity of infection of ulcer (IDSA, 2012)
  • ESR (sed rate, Westergren sedimentation rate) – order if CRP not available
    • Marker of inflammation – increases and decreases more slowly than CRP
    • Diabetic foot osteomyelitis – ulcer depth >3 mm and ESR >60 mm/hr assist in differentiation of cellulitis from osteomyelitis (IDSA, 2012)
  • Routine blood culture
    • Collect prior to antibiotic administration in all suspected cases
    • ≥2 sets of cultures (aerobic and anaerobic) should be obtained from different draws (IDSA, 2015)
    • Positive cultures may preclude need for bone biopsy
    • Positive in up to half of cases
  • Tissue culture
    • Superficial culture not useful
    • Bone sample necessary unless organism identified in blood
    • Bone or deep tissue obtained at debridement, or imaging-guided or surgical biopsy/aspirate
  • Procalcitonin
    • Use in conjunction with other inflammatory markers (acute phase reactant)
    • Elevated in severe bacterial disease (eg, sepsis)
    • Being evaluated as assessment of osteomyelitis disease severity
  • Other organism testing for vertebral osteomyelitis (rare organisms)
    • Test if risk factors or epidemiology appropriate or after no growth of bacterial cultures
    • Blood cultures and serologic tests for Brucella recommended for patients with vertebral osteomyelitis in endemic areas
    • Obtain fungal cultures if patient is at risk for fungal vertebral osteomyelitis due to risk factors or epidemiologic factors
    • Purified protein derivative (PPD) or interferon – gamma release assay for mycobacterium tuberculosis (TB) for at-risk patients
  • Polymerase chain reaction (PCR)
    • Not widely available; may be useful if all cultures are negative
    • Most useful for Bartonella henselae and Kingella kingae

Imaging Studies

Differential Diagnosis

  • C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)
    • Recommended after 4 weeks of antimicrobial therapy for vertebral osteomyelitis to evaluate response (IDSA, 2015)
    • CRP likely as effective alone

Osteomyelitis is an infection of the bone acquired hematogenously or by contiguous site infection. In children, hematogenous spread is more common, and the long bones are more often infected. In adults, hematogenously seeded osteomyelitis is seen; however, extension from contiguous sites is more likely. Diabetic foot ulcers and pressure sores are common predisposing conditions.

Epidemiology

  • Incidence (Kremers, 2015)
    • 21.8/100,000 person-years (U.S. adults)
    • 8.8/100,000 (U.S. children)
  • Sex – M>F
    • Children – more than 50% occur in children <5 years
    • Adults – incidence increases with age 

Risk Factors

  • Children
    • Blunt trauma
    • Postoperative
  • Adults
    • Peripheral vascular disease
    • Diabetes mellitus
    • Renal or hepatic failure
    • Immunosuppression
    • Malignancy
    • Neuropathy
    • Intravenous drug use
    • Trauma
    • Surgery – particularly prosthetic implants

Organisms

Clinical Presentation

  • Constitutional – fever, nonspecific pain
  • Soft tissue inflammation overlying area of osteomyelitis
  • Open and nonhealing wound over area of bone
  • Vertebral disease – may present with severe back pain
  • Children
    • Limping, reluctance to walk
    • Fever
    • Focal tenderness
    • Swelling
Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry

Sedimentation Rate, Westergren (ESR) 0040325
Method: Visual Identification

Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification

Limitations 

Limited to University of Utah Health Sciences Center only

Bone Culture and Gram Stain 0060103
Method: Culture/Identification

Procalcitonin 0020763
Method: Immunofluorescence

Guidelines

ACR Appropriateness Criteria: Suspected Osteomyelitis of the Foot in Patients with Diabetes Mellitus. American College of Radiology. Reston, VA [Last review date 2012; Accessed: May 2017]

Berbari EF, Kanj SS, Kowalski TJ, Darouiche RO, Widmer AF, Schmitt SK, Hendershot EF, Holtom PD, Huddleston PM, Petermann GW, Osmon DR. 2015 Infectious Diseases Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adults. Clin Infect Dis. 2015; 61(6): e26-46. PubMed

Choosing Wisely. An initiative of the ABIM Foundation. [Accessed: Sep 2017]

Hingorani A, LaMuraglia GM, Henke P, Meissner MH, Loretz L, Zinszer KM, Driver VR, Frykberg R, Carman TL, Marston W, Mills JL, Murad MH. The management of diabetic foot: A clinical practice guideline by the Society for Vascular Surgery in collaboration with the American Podiatric Medical Association and the Society for Vascular Medicine. J Vasc Surg. 2016; 63(2 Suppl): 3S-21S. PubMed

Lipsky BA, Berendt AR, Cornia PB, Pile JC, Peters EJ, Armstrong DG, Deery G, Embil JM, Joseph WS, Karchmer AW, Pinzur MS, Senneville E, Infectious Diseases Society of America. 2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections. Clin Infect Dis. 2012; 54(12): e132-73. PubMed

General References

Calhoun JH, Manring MM. Adult osteomyelitis. Infect Dis Clin North Am. 2005; 19(4): 765-86. PubMed

Hatzenbuehler J, Pulling TJ. Diagnosis and management of osteomyelitis. Am Fam Physician. 2011; 84(9): 1027-33. PubMed

Kremers HM, Nwojo ME, Ransom JE, Wood-Wentz CM, Melton J, Huddleston PM. Trends in the epidemiology of osteomyelitis: a population-based study, 1969 to 2009. J Bone Joint Surg Am. 2015; 97(10): 837-45. PubMed

Palestro CJ, Love C, Miller TT. Infection and musculoskeletal conditions: Imaging of musculoskeletal infections. Best Pract Res Clin Rheumatol. 2006; 20(6): 1197-218. PubMed

Peltola H, Pääkkönen M. Acute osteomyelitis in children. N Engl J Med. 2014; 370(4): 352-60. PubMed

Schmitt SK. Osteomyelitis. Infect Dis Clin North Am. 2017; 31(2): 325-338. PubMed

Medical Reviewers

Content Reviewed: 
May 2017

Last Update: September 2017