Adult Osteomyelitis
Section snippets
Classification systems
Physicians usually use one of two classification systems to describe osteomyelitis. Waldvogel and coworkers [1], [2], [3] classified bone infections as either hematogenous (derived from or transported by blood) or osteomyelitis secondary to a contiguous focus of infection. Contiguous-focus osteomyelitis is also subclassified as with or without vascular insufficiency. Either hematogenous or contiguous-focus osteomyelitis may be further classified as acute or chronic. Acute disease is defined as
Hematogenous osteomyelitis
Hematogenous osteomyelitis accounts for approximately 20% of cases of osteomyelitis in adults. The number of adult cases may be increasing, however, as the mean age of population rises in the United States and other developed countries [7]. For reasons not yet clear, it is more common in males, regardless of age. The vertebrae are the most common site of infection in adults, but hematogenous osteomyelitis also occurs in the long bones, pelvis, and clavicle [8].
Primary hematogenous osteomyelitis
Vertebral osteomyelitis
Vertebral osteomyelitis is primarily a disease of adults, with most patients more than 50 years old. Generally, incidence increases progressively with each successive decade of life. Men are affected about twice as often as women. Before the development of antibiotics, vertebral osteomyelitis was fatal in about a quarter of all patients [9]. Mortality is now rare, but a delay in diagnosis may lead to devastating complications.
Pyogenic vertebral osteomyelitis usually has a hematogenous origin,
Contiguous-focus osteomyelitis without generalized vascular insufficiency
In contiguous-focus osteomyelitis, bacterial organisms may be directly inoculated into bone at the time of trauma, spread from a nearby soft tissue infection, or spread by nosocomial contamination. Common factors in this form of osteomyelitis include surgical reduction and internal fixation of fractures, prosthetic devices, open fractures, and chronic soft tissue infections. Although S aureus is the most commonly isolated organism, multiple pathogens are usually isolated from infected bone,
Contiguous-focus osteomyelitis with generalized vascular insufficiency
Most patients in this category suffer from diabetes mellitus, and the small bones of the feet are most commonly infected (Fig. 2). Inadequate tissue perfusion, which blunts local tissue response, may predispose patients to infection, which most often is caused by minor trauma to the feet. Multiple organisms are usually isolated from bone, most commonly coagulase-positive and -negative staphylococci, Streptococcus spp, Enterococcus spp, gram-negative bacilli, and anaerobic organisms.
The
Chronic osteomyelitis
Both hematogenous and contiguous-focus osteomyelitis can become chronic. Chronic osteomyelitis is easily recognized when it occurs in a patient with a history of osteomyelitis who experiences a recurrence of pain, erythema, and swelling in association with a draining sinus. Diagnosis is more challenging in patients with a painful orthopedic prosthesis, a decubitus ulcer, a foot ulcer, or Charcot's foot associated with peripheral vascular disease or diabetes. The infection usually does not begin
Diagnosis
Osteomyelitis can often be difficult to diagnose. The intensity of inflammation, infection duration and site, vascularity, the presence or absence of a foreign body, and the presence or absence of associated pathology all affect the accuracy of any test. No noninvasive test can definitively establish or exclude osteomyelitis in complicated cases. The difficulties with diagnosis were illustrated by Newman and coworkers [17] in a study of diabetic patients with foot ulcers. As determined by bone
Treatment
Appropriate therapy includes adequate drainage, thorough debridement, dead space management, wound protection, and specific antimicrobial coverage. If the host is compromised, an effort is made to correct or improve defects. Of particular significance are good nutrition and, if applicable, a smoking-cessation program in addition to dealing with specific abnormalities, such as diabetes. An attempt is made to improve the nutritional, medical, and vascular status of the patient and to provide
Hemodialysis patients
Osteomyelitis sometimes occurs as a complication of hemodialysis. S aureus and S epidermis are common blood isolates in hemodialysis patients with indwelling cannulae that create portals for bacterial entry. Bone infections are probably hematogenous in origin, with the ribs and thoracic vertebral column the most common sites of involvement. Diagnosis of osteomyelitis is usually made 12 to 72 months after hemodialysis is initiated. The infection may not be recognized, because the clinical signs
Summary
Adult osteomyelitis remains difficult to treat, with considerable morbidity and costs to the health care system. Bacteria reach bone through the bloodstream, from a contiguous focus of infection, from penetrating trauma, or from operative intervention. Bone necrosis begins early, limiting the possibility of eradicating the pathogens, and leading to a chronic condition. Appropriate treatment includes culture-directed antibiotic therapy and operative debridement of all necrotic bone and soft
References (100)
- et al.
Osteomyelitis
Lancet
(2004) - et al.
Bone scanning: radionuclidic reaction mechanisms
Semin Nucl Med
(1976) Diagnosis of chronic and postoperative osteomyelitis with gallium 67 citrate scans
Am J Surg
(1975)Magnetic resonance imaging of musculoskeletal infections
Radiol Clin North Am
(1986)Imaging of osteomyelitis in the mature skeleton
Radiol Clin North Am
(2001)Outpatient parenteral antimicrobial therapy for osteomyelitis
Infect Dis Clin North Am
(1998)Prolonged suppression of infection in total hip arthroplasty
J Arthroplasty
(1988)- et al.
Update on the diagnosis and management of osteomyelitis
Clin Podiatr Med Surg
(1996) - et al.
Soft-tissue coverage for the treatment of osteomyelitis of the lower part of the leg
Mayo Clin Proc
(1986) - et al.
Update on chronic osteomyelitis
Clin Plast Surg
(1991)