Chronic Osteomyelitis in Child
CIM Case: Chronic Osteomyelitis in Child
Clinical Scenario
Patient: 12-year-old girl Presentation: 3 months post closed reduction of proximal humerus fracture treated with hanging cast, ongoing pain and now developing intermittent discharge from anterior shoulder Relevant history: Initially uncomplicated fracture from netball injury, treated in ED with closed reduction and hanging cast for 6 weeks, slow to recover with persistent dull ache, low-grade fevers (37.8°C) noted at home, no antibiotic treatment previously Examination findings:
- Sinus tract over anterolateral proximal humerus with purulent discharge
- Surrounding erythema and induration
- Reduced range of motion (elevation 90°, external rotation 20°)
- No acute systemic sepsis
- Afebrile currently
- Axillary lymphadenopathy
- Otherwise well, no weight loss
Investigations Provided
Laboratory Results
| Test | Result | Normal Range | Interpretation |
|---|---|---|---|
| Hb | 112 g/L | 115-155 g/L | ↓ Mild anaemia (chronic infection) |
| WCC | 10.2 ×10⁹/L | 4-11 ×10⁹/L | Normal (common in chronic infection) |
| Platelets | 380 ×10⁹/L | 150-400 ×10⁹/L | Upper normal (reactive) |
| CRP | 42 mg/L | <5 mg/L | ↑ Elevated |
| ESR | 65 mm/hr | <10 mm/hr | ↑ Significantly elevated |
| Albumin | 32 g/L | 35-50 g/L | ↓ Low (chronic inflammation) |
Imaging
Image 1: AP and Lateral Radiographs of Right Humerus
Radiological features:
- Fracture healed in acceptable alignment
- Periosteal reaction with cortical irregularity around proximal metaphysis
- Central area of lucency with sclerotic rim (Brodie's abscess/sequestrum)
- New bone formation laterally (involucrum)
- Cloaca visible (draining tract through cortex)
- No pathological features of tumour
Image 2: MRI of Right Proximal Humerus
MRI findings:
- 3cm intramedullary abscess in proximal humeral metaphysis
- Cortical breach with soft tissue extension
- Surrounding bone oedema on STIR sequences
- Sinus tract extending to skin surface
- No joint involvement
- Physis appears intact
Questions & Model Answers
What is the diagnosis and how does chronic osteomyelitis develop?
How would you classify this infection and what investigations would you perform?
What are the principles of surgical management?
How would you manage antibiotic therapy?
How do you manage the dead space and what are the options for soft tissue coverage?
What are the potential complications and what is the prognosis?
Key Teaching Points
Pattern Recognition
This pattern suggests Chronic Osteomyelitis:
- Prior bone insult (fracture, surgery, haematogenous)
- Prolonged symptoms >6 weeks
- Draining sinus tract
- Low-grade systemic features (mild anaemia, raised ESR/CRP)
- Imaging showing sequestrum, involucrum, cortical irregularity
Distinguish from Acute Osteomyelitis:
| Feature | Acute | Chronic |
|---|---|---|
| Duration | <2 weeks | >6 weeks |
| Systemic symptoms | High fever, toxic | Low-grade, may be afebrile |
| WCC | Elevated | Often normal |
| Imaging | Soft tissue swelling, later periosteal reaction | Sequestrum, involucrum, cloaca |
| Treatment | Antibiotics often sufficient | Surgery almost always required |
Critical Management Points
- Deep tissue culture is essential - never treat on swab alone
- Debride to paprika sign - all remaining bone must bleed
- Rifampicin for biofilm - but never as monotherapy
- Manage dead space - beads, cement, or flap
- Prolonged antibiotics - 6-12 weeks minimum
- CRP tracks response - ESR slower to change
- Second-look if needed - don't hesitate to re-debride
Common Examiner Follow-ups
Q: "What is the role of hyperbaric oxygen therapy?"
Hyperbaric oxygen therapy (HBOT):
- Adjunctive therapy for refractory chronic osteomyelitis
- Increases tissue oxygen tension
- Enhances neutrophil bacterial killing
- Promotes angiogenesis in ischaemic tissue
- Potentiates some antibiotics
- Evidence mixed but may be considered for:
- Refractory cases after multiple debridements
- Compromised hosts (diabetes, vascular disease)
- Extensive involvement
- Not first-line treatment
Q: "How would you manage a growth disturbance from physeal involvement?"
If physis is involved and damaged:
- Monitor for growth arrest with serial X-rays
- Compare limb lengths clinically and radiographically
- If bar forms: Consider bar excision if <50% physis and 2+ years growth remaining
- If significant LLD predicted: Contralateral epiphysiodesis or limb lengthening
- For this patient: Physis appears intact on MRI - monitor but low risk
Q: "What if this patient had a pathological fracture through the infected bone?"
Management of pathological fracture through osteomyelitis:
- Priority: Treat infection AND stabilise bone
- Debridement as usual
- Stabilisation options:
- External fixation (preferred - keeps hardware outside infection)
- Plate fixation with antibiotic cement coating
- Antibiotic-coated intramedullary nail (newer)
- Bone grafting after infection controlled (staged)
- Avoid standard internal fixation without addressing infection
- May need longer antibiotics and multiple stages
Q: "What is the role of PET-CT in osteomyelitis?"
FDG PET-CT role:
- Differentiates infection from tumour (both can be hot)
- Detects extent of infection not seen on MRI
- Useful when MRI contraindicated (metalwork, pacemaker)
- Can detect multifocal disease
- Monitors treatment response
- Limitations: radiation exposure, availability, cost, less anatomical detail than MRI
Related Topics
- Acute Paediatric Osteomyelitis
- Brodie's Abscess
- Septic Arthritis
- Prosthetic Joint Infection
- Antibiotic Bone Penetration
- Negative Pressure Wound Therapy