Osteomyelitis

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

Indications for Testing

  • History and physical examination suggestive of osteomyelitis
  • Chronic, nonhealing ulcer that can be probed to the bone (particularly in a diabetic patient)

Laboratory Testing

  • CBC – may help in differentiating bacterial etiology versus other cause
    • Frequently shows leukocytosis and left shift to immature forms
    • May be normal in chronic osteomyelitis
  • C-reactive protein (CRP)
  • Procalcitonin may be helpful in children – not often used and does not outperform CRP
  • Blood culture – in all suspected cases
    • Requires 3-5 sets from separate venipuncture sites
    • Positive in ≤50% of children
  • Bone culture – necessary for most patients
  • PCR – not widely available; may be useful if all cultures are negative

Imaging Studies

  • Plain x-ray films – may not demonstrate presence of osteomyelitis until 10-14 days after infection is established
    • Negative film does not rule out diagnosis
    • Evidence for osteomyelitis on film – periosteal lifting or lytic lesions
  • Bone scan with technetium-99 pyrophosphate – most useful if 3-phase scintigraphy is used
    • 90% sensitive in long bone osteomyelitis
  • MRI – probably most sensitive imaging tool but may not distinguish infections from other bone disorders
    • Evidence for osteomyelitis – bone marrow edema, abscesses
    • May need to use 18FDG-PET for vertebral osteomyelitis
  • CT – not as sensitive as MRI; not useful if metal is near the infection
    • In acute osteomyelitis, CT can depict changes earlier in disease process than plain imaging

Differential Diagnosis

  • CRP – may be helpful in gauging success of therapy
    • Declining values suggest favorable treatment response

Osteomyelitis is an infection of the bone acquired hematogenously or by contiguous site infection.

Epidemiology

  • Incidence – 2/10,000
  • Sex – M>F (slight risk increases through childhood, peaks in adolescence, and falls to a low ratio in adults)
  • Age – bimodal age distribution
    • Children – acute hematogenous osteomyelitis
    • Adults – direct trauma/contiguous focus osteomyelitis; vertebral osteomyelitis

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

Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification

Limitations 

Limited to the University of Utah Health Sciences Center only

C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry

Bone Culture and Gram Stain 0060103
Method: Culture/Identification

Guidelines

American Society for Clinical Pathology. Choosing Wisely - Five Things Physicians and Patients Should Question. An initiative of the ABIM Foundation. [Last revision Feb 2015; Accessed: Jan 2016]

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

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

Medical Reviewers

Last Update: August 2016