Osteomyelitis David Thom, MD, PhD Associate Professor Family

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Osteomyelitis David Thom, MD, PhDAssociate
ProfessorFamily Community Medicine
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Definition

• An infective inflammatory process with bone
  destruction
• Open biopsy with histology and culture is a
  gold standard

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Classification of Osteomyelitis

• Age (adult v. child)
• Site (foot, vertebra, long bone)
• Source (trauma/surgery, hematogenous,
  or contiguous spread/cellulitis,)
• Presence or absence of foreign body (hardware)
• Acute vs. chronic
• Severity
• Comorbidity (e.g., diabetic, sickle cell)
• Organism

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Focus of Current Talk

• Acute osteomyelitis in the diabetic foot
• Acute vertebral osteomyelitis
• Chronic osteomyelitis

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Acute Diabetic Foot Osteomyelitis Risk Factors

• Virtually always associated with ulcer
• In about 2/3 of infected ulcers
• Less than one-third being clinically diagnosed 1

1. Newman LG et al. JAMA 19912661246
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Acute Diabetic Foot Osteomyelitis Risk Factors

• More common with1
• ulcer for gt 2 weeks
• ulcer gt 2 cm by 2 cm
• ulcer depth gt 3 mm
• ulcer over bone

1. Newman LG et al. JAMA 19912661246
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Acute Diabetic Foot Osteomyelitis Risk Factors

• Predisposing factors
• Poor vascularity
• Neuropathy
• Poor glycemic control

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Acute Diabetic Foot Osteomyelitis Signs and
Symptoms

• No sign or symptom is sensitive
• Pain, inflammation, fever may all be absent
  (and often are)
• Visualizaton has a specificity of 100
• Probing to bone specificity of 851
• ESR gt 70 has a specificity of 100

1. Grayson ML et al. JAMA 1995273721
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Acute Diabetic Foot Osteomyelitis Testing

• Blood cultures even if not febrile
• Wound cultures not useful
• Open bone biopsy recommended, but not done at
  SFGH
• Plain films useful if positive (may not show
  changes for 2 to 3 weeks however)
• MRI is best imaging modality (sensitivity88,
  specificity100)1

1. Williamson MR et al J Vasc Surg 199624266
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Acute Diabetic Foot Osteomyelitis Testing

• Radionucleide scanning if MRI not possible
• Tc-99 is most sensitive
• Indium or gallium-labeled leukocyte test is
  most specific
• Both are pretty poor compared to MRI

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Acute Diabetic Foot Osteomyelitis Testing

• In practice, diagnosis often made without
  advanced imaging

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Acute Diabetic Foot Osteomyelitis Organisms

• Staph aureus most common
• Other players are
• Streptococcus sp.
• Enterococcus sp.
• Coag negative Staph
• Gram negative aerobes
• Anaerobes

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Acute Diabetic Foot Osteomyelitis Empiric
treatment

• Outpatient treatment with ciprofloxin is an
  option if you have a sensitive organism and a
  compliant patient
• Dream on
• In setting where MRSA is possible and no
  organism isolated, use vancomycin
• That would be us

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Acute Diabetic Foot OsteomyelitisDuration of
Treatment and Follow-up

• 4 to 6 weeks IV antibiotics if medical
  treatment alone
• 2 to 3 weeks if combined with surgical
  treatment
• Can follow CRP (more responsive then ESR) for
  reoccurrence or failure of treatment response
• Medical therapy alone has higher failure rate
  then with sugery1

1. Tan JS, et al. Clin Infect Dis 199623266.
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Vertebral Osteomyelitis Risk Factors and
Etiology

• Risk factors
• Male
• Age gt 50
• IVDU
• Etiology
• Virtually always hematogenous
• Lumbar more common then cervical

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Vertebral Osteomyelitis Signs and Symptoms

• Localized pain and tenderness
• Diagnosis often missed or delayed

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Vertebral Osteomyelitis Testing

• Plain films
• MRI best
• CT-guided needle biopsy

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Vertebral Osteomyelitis Organisms

• Staph Aureus in about 50
• Other organisms
• Gram negative aerobes
• Streptococcus sp.
• Tuberculosis
• Pseudomonas and candida in IVDU

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Vertebral Osteomyelitis Empiric Treatment

• Nafcillin plus cefotxime, ceftazidim or cipro
• If possible MRSA, then vancomycin

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Vertebral OsteomyelitisDuration of Treatment
and Follow-up

• 6 to 12 weeks IV antibiotics if medical
  treatment alone
• Surgical treatment indicated if
• abscess
• cord compression
• failure of medical treatment
• Can follow CRP for reoccurrence or failure of
  treatment response

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Chronic Osteomyelitis

• No established definition
• Generally weeks to years
• Includes bone necrosis with sequestion
• MRI useful in diagnosis
• Avascular sequestra make treatment with abx
  alone problematic
• No agreed upon treatment regimen