Define osteomyelitis.
infection of the bone
Epidemiology.
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
Describe the routes of infection.
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)
What are risk factors for osteomyelitis?
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
List the most common causes.
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
List clinical features of the acute osteomyelitis and subacute osteomyelitis.
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
Describe findings of chronic osteomyelitis.
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
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