The most common mode by which organisms reach the bone is by hematogenous spread (i.e., either bacteremia or fungemia) from a distant site.1

Acute bacterial osteomyelitis often arises from a pyogenic skin infection such as a boil, but many sources are undetected.

Mycobacterial and fungal osteomyelitis often arise from the initial site of infection in the lung.

In children, hematogenous spread tends to result in osteomyelitis located at the end of long bones (at the metaphyses) that are richly endowed with blood vessels.

In adults, hematogenous spread results most commonly in vertebral osteomyelitis and discitis, not osteomyelitis of the long bones.

Osteomyelitis also occurs by direct extension from an infected contiguous site such as a skin or soft tissue infection. It also can occur following trauma that results in an open fracture and direct contamination of thebone.

Chronic osteomyelitis tends to occur in the lower extremity, especially in diabetics who often have vascular insufficiency. They are predisposed to skin and soft tissue infections that extend into the bone.

 

Osteomyelitis is an infection of the bone.

The term osteo refers to bone, and myelo refers to the bone marrow.

Osteomyelitis is classified as either acute or chronic.

 

 

 

 

Empiric therapy for acute osteomyelitis should include drugs that are bactericidal, penetrate well into bone, and include coverage for S. aureusVancomycin, nafcillin, orcephalexin administered parenterally can be used. Vancomycin is often used until the culture results and the sensitivity of the organism are known. The duration of therapy ranges from 3 to 6 weeks or longer.

Surgical debridement of chronic osteomyelitis lesions,

especially to remove sequestra, is important to minimize the risk of relapse.

 

 

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History

 
 
 
 

 

Physical Exam

 

Laboratory Tests

X-ray

 

Essentail Criteria to Establish Diagnosis

 

 

Chemoprophylaxis is typically not employed. Proper foot care in diabetics can prevent osteomyelitis.

 

Relapses tend to occur in chronic osteomyelitis more than in acute osteomyelitis,

 

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A 12-year-old girl was playing soccer when she began to limp. She has pain in her right leg and right upper thigh. Her temperature is 102°F (38.9°C). Radiography of the femur reveals that the periosteum is eroded, findings suggestive of osteomyelitis. Blood culture yields gram-positive bacteria. The most likely etiologic agent is which of the following?

The correct answer is C.

C. Staphylococci, especially S. epidermidis, are normal flora of the human skin and respiratory and gastrointestinal tracts. Nasal carriage of S. aureus, the pathogen, occurs in 20% to 50% of humans. Abscesses are the typical lesions seen in cases of S. aureus infection. From any one focus, organisms may enter the bloodstream and lymphatics to spread to other parts of the body. In osteomyelitis, the primary focus is generally in a terminal blood vessel of the metaphysis of a long bone, which may lead to necrosis of bone and chronic suppuration. S. saprophyticus is usually a nonpathogenic normal flora organism. Listeria is usually transmitted in unpasteurized dairy products, whereas Salmonella enteritidis is primarily intestinal. Streptococcus pneumoniae is primarily a respiratory pathogen, although it is an important central nervous system pathogen in children.

 

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