Localized bone pain/tenderness, ± overlying ulcer
Imaging: X-ray (late — needs 50% bone loss) → MRI (earliest, most sensitive)
Before antibiotics: Bone biopsy + culture (start antibiotics after biopsy obtained); if septic, take blood cultures and start empiric IV antibiotics without delaying for biopsy
Treat: Culture-directed IV antibiotics ×4–6 wk; surgical debridement
Order set
- MRI
- Bone biopsy + culture
- ESR/CRP, FBC
- Blood cultures
Criteria
AdmitSystemic sepsis or need for IV therapy/surgery
ICUSeptic shock
DischargeSource controlled, on directed antibiotics, OPAT plan
Never
- Give antibiotics based on a bone scan alone — get the biopsy first
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
- Sepsis
- Adjacent abscess
- Vascular compromise (diabetic foot)
Differentials
- Charcot joint
- Soft-tissue infection
- Malignancy
- Gout
Common mistakes
- Antibiotics before culture
- Relying on X-ray early
Disposition & follow-up
Culture-directed antibiotics 4–6 wk; surgical debridement.
Discharge package
MedicationsComplete directed antibiotic course (OPAT)
Follow-upID/orthopaedics; serial ESR/CRP to define treatment response/duration
Warning symptomsFever, increasing pain, discharge
💊 Treatment detail — doses & preparation
Flucloxacillinanti-staph penicillin
Dose2 g IV q6h (severe cellulitis/osteomyelitis); 500 mg–1 g PO QID step-down
PreparationIV 2 g in 50 mL NS over 30 min
MonitorLFTs (cholestatic hepatitis), Na⁺ load
Cefazolin1st-gen cephalosporin
Dose2 g IV q8h (MSSA osteomyelitis/bacteraemia)
Preparation2 g in 50 mL NS over 15–30 min
MonitorWell tolerated; renal adjust
Vancomycin IVglycopeptide
DoseLoad 25–30 mg/kg (critically ill), then 15–20 mg/kg q8–12h by levels (AUC 400–600)
PreparationDilute to ≤5 mg/mL in NS/D5W; infuse ≥60 min per 500 mg (red-man if fast)
MonitorTrough/AUC before 3rd–4th dose, creatinine, ototoxicity
📖 IDSA OsteomyelitisReviewed July 2026