Osteomyelitis

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.

Tabs Content

Clinical Overview

Diagnosis

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 (Infectious Diseases Society of America [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

Criteria for diagnosis
- American College of Radiology (ACR) Appropriateness Criteria outline recommendations for imaging for suspected osteomyelitis in diabetic foot ulcers
Imaging modalities for osteomyelitis
- 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
- Magnetic resonance imaging (MRI) – indicated after x-ray or in combination to identify extent of disease
- Labeled leukocyte bone scan – indicated in absence of MRI
- Computerized tomography (CT) scan – not as sensitive as MRI; not useful if metal is near the infection

Differential Diagnosis

Arthritis
- Septic
- Degenerative
- Crystalline
- Reactive
Juvenile rheumatoid arthritis
Neuropathic disease
Metastatic bone disease
Paget disease

Monitoring

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

Background

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

Most common organism
- Staphylococcus aureus
Diabetes mellitus, peripheral vascular disease
- Streptococcus spp
- Coagulase-positive and -negative Staphylococcus spp
- Enterococcus spp
- Anaerobic spp, often polymicrobial
Intravenous drug use
- Pseudomonas aeruginosa
Infants and children
- Staphylococcus spp
- S. pneumoniae
- Group A Streptococcus (especially post chickenpox)
- Kingella kingae
Neonates
- Group B Streptococcus
- Gram-negative species
Hemoglobinopathies
- Salmonella spp
Uncommon pathogens
- Fungal and mycobacterial pathogens

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

ARUP Lab Tests

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

Recommended Use

Initial test for differentiating bacterial from viral infection

C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry

Recommended Use

Preferred test to detect acute phase inflammation (eg, autoimmune diseases, connective tissue disease, rheumatoid arthritis, infection, or sepsis)

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

Recommended Use

Nonspecific test used to detect inflammation associated with infections, cancers, and autoimmune diseases

Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification

Recommended Use

Detect presence of bacteria in blood

Limitations

Limited to University of Utah Health Sciences Center only

Bone Culture and Gram Stain 0060103
Method: Culture/Identification

Recommended Use

Identify bacteria in bone specimens

If anaerobic infection is suspected, send specimen under anaerobic conditions

Procalcitonin 0020763
Method: Immunoassay

Medical Experts

Fisher, Mark A., PhD, D(ABMM), Medical Director, Bacteriology, and Special Microbiology, Antimicrobial Susceptibility Testing, at ARUP Laboratories; Associate Professor of Clinical Pathology, University of Utah

Genzen, Jonathan R., MD, PhD, Laboratory Section Chief, Clinical Chemistry, and Medical Director, Automated Core Laboratory, at ARUP Laboratories; Associate Professor of Clinical Pathology, University of Utah

References

Guidelines

Choosing Wisely. An initiative of the ABIM Foundation. [Accessed: Oct 2018]
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
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
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
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]

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

Content Review:

May 2017

Last Update: March 2018

Osteomyelitis

Diagnosis

Indications for Testing

Laboratory Testing

Imaging Studies

Differential Diagnosis

Monitoring

Background

Epidemiology

Risk Factors

Organisms

Clinical Presentation

ARUP Lab Tests

Medical Experts

References

Guidelines

General References

ARUP Laboratories

ARUP Websites

ARUP Consult


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	Osteomyelitis. ARUP Consult^©. Retrieved December 17, 2018, from: https://arupconsult.com/content/osteomyelitis