Osteomyelitis

Definition

• • Infection of the bone or bone marrow

  • Clasified based on

    • Causative organism (pyogenic bacteria or mycobacteria)

    • Route, duration and anatomic location of the infection

Risk Factors

• • Sickle cell anaemia

Differential diagnosis

Epidemiology

Aetiology

• • Infection via

  • bloodstream

    • contiguously from local areas of infection (as in cellulitis)

    • penetrating trauma

  • In sickel cell, the most common causative agent remains Staphylococcus aureus, but Salmonella species become proportionally more common pathogens than in healthy hosts

Clinical features

• • Pain

Pathophysiology

• • Leukocytes invade

  • Release enzymes which destroy the bone

  • Pus entry -> imparied perfusion

  • Necrosis

Investigations

• • Xray will reveal abcesses in bone as radiolucency

  • Blood / bone culture

Management

a) conservative

b) medical

• • Antibiotics

c) surgical

Prognosis

• • May develop to chronic condition

    • In sequestra (devitalised bone)

    • New bone may form around the area (involucrum)

  • Chronic osteomyelitis may be due to the presence of intracellular bacteria

    • Therefore resistant to antibiotics

  • In infants, the infection can spread to the joint and cause arthritis

  • In children, large subperiosteal abscesses can form because the periosteum is loosely attached to the surface of the bone