Overview

• Osteomyelitis → infection in the bone and bone marrow.
  • Typically occurs in the metaphysis of the long bones.
  • Most common cause is staphylococcus aureus. (Sickle cell = salmonella).
• Risk Factors → open bone fracture, orthopaedic surgery, immunocompromised, sickle cell anaemia, HIV, tuberculosis.
• Septic Arthritis →
  • Most common cause is staphylococcus aureus (gram positive cocci). Most commonly hip.
  • Sx → high grade fever, joint pain/limp, red/hot/swollen joint.
    • Kocher’s Criteria → inability to weight bear, fever >38.5ºC, WCC >12x10^9, ESR >40mm/hr.
  • Ix → joint aspiration.
  • Mx → prolonged antibiotics (IV for 2 weeks, then 4 weeks of oral). Joint aspiration (DO BEFORE ABx - get appropriate culture for treatment) to drain and dry joint.
• Reactive Arthritis →
  • Arthritis a few weeks after a GI infection or STI. HLA-B27 disease.
  • Sx → conjunctivitis, urethritis, arthritis. (can’t see, can’t pee, can’t climb a tree).
  • Mx → self-limiting and symptomatic relief.

Making Diagnosis

Clinical Features

• Refusing to use the limb or weight bear.
• Pain + Swelling + Tenderness.

Investigations

• MRI → BEST IMAGING for diagnosis.
• Blood Culture → establish causative organism.
  • Take BLOOD CULTURES BEFORE STARTING ABX.

Management Plan

• High-Dose IV Empirical Antibiotics (2-4 weeks) → flucloxacillin (clindamycin if allergic).
  • Switch to oral antibiotics (6 week course) once clinical recovery and acute-phase reactants returned to normal.
    • IV TO ORAL ONCE CRP NORMALISES.
    • BLOOD CULTURES BEFORE STARTING ABX.
• Surgical debridement of infected bone may be necessary.