Osteomyelitis ✅

🦠 In patients with Sickle cell disease → Staphylococcus aureus and Salmonella are key organisms. Osteomyelitis is an acute bacterial infection of bone that can rapidly compromise blood supply, leading to necrosis, growth plate damage, and permanent disability if treatment is delayed. Haematogenous spread is most common in children, particularly affecting metaphyseal regions.

ℹ️ About

• 🦴 Infection of bone → pain, deformity, chronic disability if untreated.
• ⏱ Surgical + paediatric + microbiological emergency.
• 🩺 Systemic risk assessment (sepsis, comorbidities) essential before starting therapy.

🧾 Aetiology

🔴 Usually haematogenous spread → infection seeds in the metaphyses of long bones (slow flow + microtrauma encourage seeding).

• 📊 Adults vs children differ in site and presentation.
• 🧬 Strong link with sickle cell disease.
• 🌍 Source: skin, urinary tract, chest infection, IVDU.

🧫 Microbiology

• 👑 Staphylococcus aureus (≈85%)
• 💉 IVDU/urosepsis → E. coli, Pseudomonas, Klebsiella
• 🍗 Salmonella (classically sickle cell)
• 👶 Neonates → Group B strep, E. coli, H. influenzae
• 🧪 Fungal in immunocompromised

🔀 Types

• 🩹 Direct: open fracture, wound, post-op
• 🩸 Indirect: blood-borne seeding

👨 Adult vs 👶 Child

• 👨 >45 yrs → vertebral osteomyelitis more common
• 🌍 TB still important worldwide
• 👶 Children → long bone metaphysis, often vague systemic features, refusal to walk
• 💉 Neonates: S. aureus, GBS, E. coli
• After 1 yr: S. aureus, Strep pyogenes, H. influenzae (↓ with vaccination)

⚠️ Risk Factors

• 🚬 Diabetes, alcoholism, chronic steroids
• 💉 IVDU → vertebral involvement
• 🧬 Immunosuppression (AIDS, transplant, chemotherapy)
• 🦠 Sickle cell disease
• 🦵 Prostheses, open fractures

🩺 Clinical

• 🔥 Toxic, febrile, rigors
• 🦴 Localised bone pain, tenderness, warmth, swelling
• 👶 Children → limp, refusal to weight bear, irritability/PUO
• ⚠️ Can mimic trauma, malignancy, or septic arthritis

🔍 Investigations

• 🩻 X-ray: baseline only, insensitive early (2–4 weeks)
• 💀 Features: sequestrum (dead bone), involucrum (new bone), Brodie’s abscess
• 🧲 MRI: gold standard – marrow oedema, soft tissue/joint involvement
• 🩺 Ultrasound: periosteal lift/collection
• ☢️ Bone scan (if MRI unavailable)
• 🧪 Blood cultures (≈50% positive)
• 📈 CRP/ESR ↑, WCC ↑
• 🔬 Biopsy/aspirate for culture BEFORE antibiotics if possible

🤔 Differentials

• Synovitis
• Trauma/fracture
• Bone tumour (Ewing’s, osteosarcoma)

💊 Management (with Microbiology input)

💡 Principles: IV antibiotics + rest/splintage + drainage if pus present. Duration guided by organism, response, and specialist advice (NICE CKS recommends 4–6 weeks IV initially, then oral if appropriate). Always follow local microbiology guidance.

• 💉 Empiric: Flucloxacillin ± Fusidic acid (UK practice) → tailor by cultures
• 🦠 Specific:
  • Staph aureus → IV penicillin or vancomycin + rifampicin if MRSA risk
  • Strep → Penicillin
  • Anaerobes → Clindamycin or Metronidazole
  • Pseudomonas → Ciprofloxacin
• 🔪 Surgery:
  • Drain/debride necrotic tissue
  • Fill dead space (flaps/bone graft)
  • Stabilise bone (internal/external fixation)
  • Amputation if uncontrolled or non-salvageable

🧪 Cases

• Case 1 - Diabetic foot osteomyelitis: 67-year-old with plantar ulcer at 1st MTP, foul discharge, probe-to-bone positive. CRP 98 mg/L, ESR 68 mm/h, X-ray shows cortical erosion; MRI confirms distal first metatarsal osteomyelitis. Start empiric IV antibiotics covering S. aureus and gram-negatives; optimise glycaemic control and perfusion. Obtain deep tissue/bone cultures and involve multidisciplinary foot team for surgical debridement ± limited resection. Duration guided by response and culture.
• Case 2 - Vertebral osteomyelitis from S. aureus bacteraemia: 59-year-old, 2 weeks severe low back pain, nocturnal sweats, recent S. aureus bacteraemia. MRI spine shows L3–L4 discitis/osteomyelitis with small epidural phlegmon. Repeat blood cultures, screen for endocarditis (TTE/TOE), start IV anti-staphylococcal therapy per local guidance. Neurosurgical input for neurological deficit, instability, or abscess. Treat 6–12 weeks guided by microbiology and response.
• Case 3 - Post-traumatic tibial osteomyelitis: 45-year-old, open tibial fracture with persistent drainage 3 months post-op. CRP 72 mg/L; MRI shows sequestrum. Deep samples off antibiotics during debridement; remove/replace hardware if unstable or biofilm suspected. Start targeted IV antibiotics then step-down oral therapy. Coordinate with orthoplastics for debridement, dead space management, and soft tissue coverage.

📖 References

• NICE CG147 – Peripheral arterial disease: diagnosis and management
• NICE CKS – Osteomyelitis (Children and Adults)
• NICE NG51 – Sepsis in children and young people