41. Osteomyelitis

infection of the bone

• Incidence: ∼ 20 per 100,000 [1]

• Hematogenous osteomyelitis

  • More common in children and adolescents

  • Incidence is increasing in adults, driven by a rise in vertebral osteomyelitis [2]

• Exogenous osteomyelitis: more common in adults

• Hematogenous osteomyelitis (endogenous osteomyelitis): caused by hematogenous dissemination of a pathogen

• Exogenous osteomyelitis: caused by a spread of bacteria (typically multiple pathogens) from the surrounding environment [4]

  • Posttraumatic: infection following deep injury (penetrating injury, open fractures, severe soft tissue injury)

  • Contiguous: spread of infection from adjacent tissue

    • Secondary to infected foot ulcer in patients with diabetes

    • Iatrogenic (e.g., postoperative infection of a prosthetic joint implant)

• Local

  • Poor tissue perfusion

  • Open fractures

  • Severe soft tissue injury

• Systemic

  • Immunosuppression

  • Systemic diseases (e.g., diabetes mellitus, atherosclerosis)

  • IV drug use

• Microbial: highly virulent pathogens

• Children and adults

• Individuals that recreationally use IV drugs [6]

• Patients with vertebral lesions

• Patients with prosthetics [7]

• Diabetic patients with foot ulcers and pressure ulcers

• Onset: within days or weeks; associated with acute bone inflammation

• Duration: < 2 weeks (acute) or 2–6 weeks (subacute) [3][8]

• Symptoms: pain at the site of infection; in patients with peripheral neuropathy the pain may be mild or absent

• Possible localized findings: point tenderness, swelling, redness, warmth

• Possible systemic findings: malaise, fever, chills

• Onset: develops slowly (over months or years) following acute infection

• Associated with: avascular bone necrosis and sequestrum formation (necrotic bone fragment that has become detached from the original bone) [9]

• Duration: typically > 6 weeks

• Symptoms: recurrent pain lasting weeks to months, maybe cyclical [3]

• Possible localized findings

  • Swelling, redness

  • Deformity

  • Impaired healing of overlying wounds

  • Local sinus tract formation, perhaps draining pus

  • Positive probe-to-bone test [10]

• Systemic findings: typically absent; may include low-grade fever, malaise