Osteomyelitis in Children

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Osteomyelitis in Children

• Dr. Robert Deane
• Janeway

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Outline

• Age
• Incidence
• Etiology
• Pathophysiology
• Presentation
• Laboratory investigations
• Imaging

• Treatment
• Surgery
• Complications
• Summary
• Special Groups

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Age / Incidence / Etiology

• 1/1000 1/ 20 000
• Male gt Female
• Pre antibiotic era 20-50 mortality

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Age / Incidence / Etiology

• Advances in treatment
• Earlier dx
• Antibiotic tx
• Surgery less delay
• Children better nourished

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Age / Incidence / Etiology

• Glasgow incidence decreased
• New Zealand. Madri gt Whites
• South Africa.. Black gt Whites
• Changing disease / Changing organism
• Seasonal Variation
• Nutritional status, climate, lifestyle

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Age / Incidence / Etiology

• H Flu
• Big cause 1970s
• 1-4 yrs
• Now decreased due to vaccinations
• Kingella Kingae
• OM in older kids
• Septic Arthritis 1-3 yrs
• Neonates separate group

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Pathophysiology

• Poorly defined
• Direct inoculation
• Hematogenous spread
• Local invasion

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Pathophysiology

• Infection
• Starts in Metaphysis
• Arteriole Loop / Venous Lakes
• Spread via Volkmans canal / Haversian system
• Endothelium Leaks

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Pathophysiology

• Few phagocytes in Zone of Hypertrophy
• Highest incidence in fastest growing bone
• Tubular gt Flat bones

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Pathophysiology

• Gaps in endothelium metaphyseal vessel
• ?
• Bacteria pass
• ?
• Adhere to Type 1 collagen
• ?
• Increase pressure in bone/ decrease blood flow
• ?
• Bone infarction / Dead Bone (sequestrum)

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Pathophysiology

• Spread via Volkman Canal
• ?
• Subperiosteal Pus
• ?
• Cortex breaks down
• ?
• May spread to joint
• Hip / Shoulder / Fibula / Proximal Humerus

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Pathophysiology

• Role of Trauma
• Rabbit experiment
• IV injection of bacteria
• With start in hematoma

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Pathophysiology

• Role of growth plate
• Over 18/12
• Impermeable to spread
• Under 18/12 infection crosses growth plate

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Pathophysiology
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Pathophysiology

• 1st osteoblasts die
• Lymphocytes release osteoclast activating factor
• Hole in bone

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Diagnosis

• Pain
• Neonate peudoparalysis
• NWB
• Failure to use limb
• Fever
• Lethargy
• Anorexia
• Swelling (neonates / older kids)

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Pathophysiology

• Bloodwork
• CBC Diff
• ESR
• CRP
• Blood Culture

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Pathophysiology

• WBC increased 30-40
• Left Shift 65
• ESR increased 91.24-36hrs
• CRP increased 974-6hrs

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Pathophysiology

• CRP
• More rapid than ESR
• 2-4 hrs ..peak 72hrs
• 10-30x normal
• Systemic ds (trauma, tumor)

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Pathophysiology

• Blood Culture
• 30-60
• Decreased with antibiotic
• Multiple cultures no significant increase in
  yield
• 48 hours to get most organisms

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Diagnosis

• Pus aspiration
• 70 bone cultures
• Septic arthritis
• Gram stain
• Lymphocyte count
• polymorphs
• gt 80 000 Septic arthritis
• gt 50 000 in some series
• 80 000 also in JRA

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Diagnosis

• Do blood and joint cultures
• One or other not always ve in same pt
• Gram stain ve 1/3 bone and joint aspirations
• Future looking for bacteria DNA / RNA

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Lab Diagnosis

• WBC not reliable
• False sense of security
• 25 increased Mayo clinic
• 65 diff abnormal
• Acute phase reactants
• Change in plasma proteins d/t cytokines

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Diagnosis

• ESR
• Nonspecific acute phase reactant
• Depends on fibrinogen concentration
• Increased 48-72 hrs
• Increased in 90 of cases
• Not affected by antibiotic tx
• CRP
• Increased in 98 of cases

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Radiology

• Plain xray
• Sensitivity 43-75
• Specificity 75-83
• Soft tissue swelling 48hrs
• Periosteal reaction 5-7d
• Osteolysis 10d to 2 wks
• (need 50 bone loss)

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Radiology

• Tc99
• 24-48hrs ve
• Bone aspiration DOES NOT give false ve
• Decreased uptake in early phase d/t increased
  pressure
• cold scan up to 100 PPV

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Radiology

• Gallium
• 48 hrs to do
• Non specific
• Indium
• I131 leucocytes
• 24hrs to prepare
• Monoclonal antibodies
• Not proven to be better

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Radiology

• MRI
• Sensitivity 83-100
• Specificity 75-100
• PPV Tc99
• Marrow and soft tissue swelling
• Good in spine and pelvis

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Radiology

• T1
• Best for acute infection
• Gadolinium helps
• Changes similar to
• Infarct
• Bruise
• Tumor
• Post surgical
• Sympathetic edema

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Radiology

• CT
• Gas
• sequestrum

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Treatment

• Mostly medical
• Sx to improve local environment
• Remove infected devitalized bone
• Decompress abscess cavity
• Timing !!
• Early antibiotic before necrosis / pus then sx
  less likely to be needed

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Treatment

• Antibiotic treatment
• Parenteral / oral combinations
• Often empirical
• Serum level more important than route
• Follow WBC / ESR/ CRP
• Organism / sensitivity

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Treatment

• Treatment Failure
• High doses
• Poor oral absorption / compliance
• Inadequate monitoring of serum levels
• Delay in Sx

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Treatment

• Previously start IV
• Follow ESR to guide switch to oral
• Newer studies
• Follow CRP
• Shorter period of tx needed
• IV 5d / total 23 d tx
• Cephalosporin 150mg/kd/day

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Treatment

• Neonates
• No studies, little evidence
• CRP / ESR not reliable
• Oral absorption not reliable
• Therefore IV neonates
• Cloxacillin

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Treatment

• Longer treatment required
• Pelvis
• Vertebrae
• Diskitis
• Calcaneus

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Treatment

• Surgical intervention
• Controversial indications
• Hole in bone not always Sx
• If purulent aspirate Sx necessary
• Sx less frequent with newer antibiotic
• 22-83 earlier studies
• 8-43 recent studies

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Treatment

• Surgery Indicated
• Subperiosteal Abscess
• Soft Tissue abscess
• Bone Abscess
• Failure of clinical response to antibiotic
• Associated septic arthritis

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Complications

• Infection Complications
• Recurrence
• Chronic osteo
• Pathologic fracture
• Growth plate injury
• Antibiotic Complications
• Diarrhea
• NV
• Rash
• Thrombocytopenia
• Neutropenia