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Osteomyelitis in Children
Dr. Robert Deane
Janeway
Outline
Age
Incidence
Etiology
Pathophysiology
Presentation
Laboratory investigations
Imaging
Treatment
Surgery
Complications
Summary
Special Groups
Age / Incidence / Etiology
1/1000 – 1/ 20 000
Male > Female
Pre antibiotic era ……20-50% mortality
Age / Incidence / Etiology
Advances in treatmentEarlier dx
Antibiotic tx
Surgery less delay
Children better nourished
Age / Incidence / Etiology
Glasgow incidence decreased
New Zealand……. Madri > Whites
South Africa…….. Black > Whites
Changing disease / Changing organism
Seasonal Variation
Nutritional status, climate, lifestyle
Age / Incidence / Etiology
H Flu
Big cause 1970’s
1-4 yrs
Now decreased due to vaccinations
Kingella Kingae
OM in older kids
Septic Arthritis 1-3 yrs
Neonates separate group
Pathophysiology
Poorly defined
Direct inoculation
Hematogenous spread
Local invasion
Pathophysiology
InfectionStarts in Metaphysis
• Arteriole Loop / Venous Lakes
Spread via Volkman’s canal / Haversian system
Endothelium Leaks
Pathophysiology
Few phagocytes in Zone of Hypertrophy
Highest incidence in fastest growing bone
Tubular > Flat bones
PathophysiologyGaps in endothelium metaphyseal vessel
Bacteria pass
Adhere to Type 1 collagen
Increase pressure in bone/ decrease blood flow
Bone infarction / Dead Bone (sequestrum)
Pathophysiology
Spread via Volkman Canal
Subperiosteal Pus
Cortex breaks down
May spread to jointHip / Shoulder / Fibula / Proximal Humerus
Pathophysiology
Role of Trauma
Rabbit experiment
IV injection of bacteria
With # start in hematoma
Pathophysiology
Role of growth plateOver 18/12
Impermeable to spread
Under 18/12 infection crosses growth plate
Pathophysiology
Pathophysiology
1st osteoblasts die
Lymphocytes release osteoclast activating factor
Hole in bone
DiagnosisPain
Neonate peudoparalysisNWBFailure to use limb
Fever
Lethargy
Anorexia
Swelling (neonates / older kids)
Pathophysiology
Bloodwork
CBC Diff
ESR
CRP
Blood Culture
Pathophysiology
WBC increased 30-40%
Left Shift 65%
ESR increased 91%……….24-36hrs
CRP increased 97%…………4-6hrs
Pathophysiology
CRPMore rapid than ESR
2-4 hrs …..peak 72hrs
10-30x normal
Systemic ds (trauma, tumor)
Pathophysiology
Blood Culture
+ 30-60%
Decreased with antibiotic
Multiple cultures no significant increase in yield
48 hours to get most organisms
Diagnosis
Pus aspiration70% bone + culturesSeptic arthritis
• Gram stain• Lymphocyte count• % polymorphs
> 80 000 = Septic arthritis> 50 000 in some series80 000 also in JRA
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
Lab Diagnosis
WBC not reliableFalse sense of security
25% increased Mayo clinic
65% diff abnormal
Acute phase reactantsChange in plasma proteins d/t cytokines
Diagnosis
ESRNonspecific acute phase reactant
Depends on fibrinogen concentration
Increased 48-72 hrs
Increased in 90% of cases
Not affected by antibiotic tx
CRPIncreased in 98% of cases
Radiology
Plain xraySensitivity 43-75%Specificity 75-83%
Soft tissue swelling 48hrsPeriosteal reaction 5-7dOsteolysis 10d to 2 wks
(need 50% bone loss)
Radiology
Tc9924-48hrs +ve
Bone aspiration DOES NOT give false +ve
Decreased uptake in early phase d/t increased pressure
“cold” scan up to 100% PPV
RadiologyGallium
48 hrs to do Non specific
IndiumI131 leucocytes24hrs to prepare
Monoclonal antibodiesNot proven to be better
Radiology
MRISensitivity 83-100%
Specificity 75-100%
PPV = Tc99
Marrow and soft tissue swelling
Good in spine and pelvis
Radiology
T1Best for acute infection
Gadolinium helps
Changes similar to• #
• Infarct
• Bruise
• Tumor
• Post surgical
• Sympathetic edema
Radiology
CTGas
sequestrum
Treatment
Mostly medicalSx to improve local environmentRemove infected devitalized boneDecompress abscess cavity
Timing !!Early antibiotic before necrosis / pus then sx less likely to be needed
Treatment
Antibiotic treatmentParenteral / oral combinations
Often empirical
Serum level more important than route
Follow WBC / ESR/ CRP
Organism / sensitivity
Treatment
Treatment FailureHigh doses
Poor oral absorption / compliance
Inadequate monitoring of serum levels
Delay in Sx
Treatment
Previously start IV Follow ESR to guide switch to oral
Newer studiesFollow CRP
Shorter period of tx neededIV 5d / total 23 d txCephalosporin 150mg/kd/day
Treatment
NeonatesNo studies, little evidence
CRP / ESR not reliable
Oral absorption not reliable
Therefore IV neonates
Cloxacillin
Treatment
Longer treatment requiredPelvis
Vertebrae
Diskitis
Calcaneus
Treatment
Surgical interventionControversial indicationsHole in bone not always SxIf purulent aspirate Sx necessary
Sx less frequent with newer antibiotic22-83% earlier studies8-43% recent studies
Treatment
Surgery Indicated
Subperiosteal Abscess
Soft Tissue abscess
Bone Abscess
Failure of clinical response to antibiotic
Associated septic arthritis
ComplicationsInfection Complications
RecurrenceChronic osteoPathologic fractureGrowth plate injury
Antibiotic ComplicationsDiarrheaN+VRashThrombocytopeniaNeutropenia