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Osteomyelitis is an infection by microorganisms that invade bone. Three pathogenetic routes of infection define the major forms of osteomyelitis, with pathogens reaching osseous tissue by (1) hematogenous seeding, (2) contamination accompanying surgical and nonsurgical trauma (termed "introduced" infection), or (3) spread from infected contiguous tissue osteomyelitis and bone infection.


Although virtually all microorganisms can infect bone, bacteria are the usual pathogens, and staphylococci are the most prominent etiologic agents. Staphylococcus aureus causes approximately 60% of hematogenous and introduced infections and is a principal agent when osseous sepsis spreads by contiguity. S. epidermidis has become a major pathogen in bone infections.


The anatomic location of hematogenous osteomyelitis is age-dependent. From birth to puberty the long bones of the extremities are the most frequently involved. In adults blood-borne osteomyelitis generally affects the spine, because vertebrae become more vascular than other skeletal tissue.


In childhood hematogenous osteomyelitis the initial infective site is the long bone metaphysis due to its large blood flow. In adults bacteremias seed vertebral bodies preferentially at the more vascular anterior end-plates. Osteomyelitis commonly involves two mechanisms.


In the classic presentation of childhood hematogenous osteomyelitis, fever, chills, and malaise are present but are frequently absent in the other forms of bone infection. Localized pain is a characteristic feature of osteomyelitis, with overlying erythema, warmth, and swelling variably observed. Limb

Hematogenous vertebral osteomyelitis often presents with back pain, spine tenderness, and low-grade fever following urinary tract instrumentation or infection (30%), skin infection (13%), or respiratory infection (11%). The septic process extending beyond the vertebral column produces suppuration at the

Osteomyelitis after trauma or bone surgery is usually associated with persistent or recurrent fevers, increasing pain at the operative site, and poor incisional healing, which is often accompanied.


Diagnosis requires both confirming the osseous site of involvement and identifying the etiologic microbes. Bone infection must be differentiated from septic arthritis and bursitis, cellulitis and soft tissue abscesses, bone fractures, and neoplasms, as well as bone infarcts seen with sickle cell hemoglobinopathy and Gaucher's disease. Anatomic delineation of bone infection depends largely on

Technetium diphosphonate bone scans, gallium-citrate scans, and indium-labeled leukocyte scintigraphy are far more sensitive than radiography and usually reveal increased radionuclide uptake when


Acute osteomyelitis is curable with adequate antimicrobial therapy and surgical debridement when necessary. Parenterally administered antibiotics are usually employed, but oral therapy is also effective when the pathogen is sufficiently susceptible and gastrointestinal absorption is ensured.


Inadequate therapy of acute osteomyelitis results in relapsing infection and progression to chronic osteomyelitis; therefore, definitive treatment of acute infection is obligatory.