OSTEOMYELITIS

Infection of bone by pus-forming bacteria, mainly affecting older children and adults.

Causes

  •  Any type of bacterium but most commonly S.aureus, following infection elsewhere in the body
  • Risk factor: sickle cell disease (causative agent mostly S. Aureus, Salmonella also common)

Clinical features

Acute osteomyelitis

  • Onset is usually over several days
  • Fever, usually high but may be absent, especially in neonates
  • Pain (usually severe)
  • Tenderness and increased “heat” at the site of infection, swelling of the surrounding tissues and joint
  • Reduced or complete loss of use of the affected limb
  • The patient is usually a child of 4 years or above with reduced immunity, but adults may also be affected
  • History of injury may be given, and may be misleading, especially if there is no fever

Chronic osteomyelitis

  • May present with pain, erythema, or swelling, sometimes in association with a draining sinus tract
  • Deep or extensive ulcers that fail to heal after several weeks of appropriate ulcer care (e.g. in diabetic foot), and
    non-healing fractures, should raise suspicion of chronic osteomyelitis

Differential diagnosis

  • Infection of joints
  • Injury (trauma) to a limb, fracture (children)
  • Bone cancer (osteosarcoma, around the knee)
  • Pyomyositis (bacterial infection of muscle)
  • Cellulitis
  • Sickle-cell disease (thrombotic crisis)

Investigations

  • X-ray shows
    • Nothing abnormal in first 1-2 weeks
    • Loss of bone density (rarefaction) at about 2 weeks
    • May show a thin “white” line on the surface of the infected part of the bone (periosteal reaction)
    • Later, may show a piece of dead bone (sequestrum)
  • Blood: CBC, ESR, C&S: Type of bacterium may be detected

Management

Patients with suspected osteomyelitis need to be referred to hospital for appropriate management.

  • Immobilize the limb, splint
  • Provide pain and fever relief with paracetamol, or ibuprofen
  • Refer URGENTLY to hospital
  • Admit and elevate affected limb
  • Cloxacillin 500 mg IV every 6 hours for 2 weeks. Continue orally for at least 4 weeks (but up to
    3 months) Child: 50 mg/kg every 6 hours See pyogenic arthritis for other antibiotic treatments
  • Osteomyelitis in SCD: see section 11.1.3
  • Surgical intervention may be indicated in the following cases:
  • Drainage of subperiosteal and soft tissue abscesses, and intramedullary purulence
    • Debridement of contiguous foci of infection  (which also require antimicrobial therapy)
    • Excision of sequestra (i.e. devitalized bone)
    • Failure to improve after 48-72 hours of antimicrobial therapy

Chronic osteomyelitis

  • Surgery and antibiotics