Rare bone infections "excluding the spine"

Bone infections are usually due to haematogenous spread from distant infected organs. Spread of local sepsis or contamination of open wounds are less frequent routes of infection. The commonest cause of osteomyelitis is Staphylococcus aureus. The term rare bone infections refers to diseases where only a few percent affect bone or diseases which are essentially rare; these include bacteria, fungi, parasites and non-specific conditions. Common examples are tuberculosis, salmonellosis, brucellosis, hydatidosis, madura, actinomycosis, aspergillosis and American fungal infections. Certain bone infections have become exceedingly rare, particularly atypical mycobacteria, viral embryopathies and spirochaetes. Rare bone infections are encountered in many parts of the world commonly in the tropics and in the U. S. Immunocompromise and ease of travel can lead to increased incidence. A high index of clinical suspicion is necessary for diagnosis. Specific laboratory diagnosis is not always possible. Radiographs, computed tomography, isotope studies and magnetic resonance are useful but may not make the diagnosis. Aspiration or biopsy is necessary. Rare bone infections may simulate non-infective bone lesions.