OSTEOMYELITIS

infection of bone tissue, usually occurring in childhood, most commonly caused by Staphylococcus aureus. The infectious organism reaches the bone via the bloodstream or by extension from a local injury and produces an inflammation with destruction of the cancellous (porous) bone and marrow, loss of blood supply, and bone death. Living bone around the infected area walls it in, forming a sequestrum, the contents of which are gradually resorbed as the lesion is repaired. In chronic osteomyelitis, infection remains active, and periodic drainage to the surface via sinus tracts may occur. Symptoms include fever, chills, and bone pain; later, swelling and redness may develop around the area of infection. Formerly a disease with high mortality, osteomyelitis today is usually controlled with antibiotics. Osteomyelitis may occur as a complication of many diseases, such as typhoid, syphilis, tuberculosis, or sickle-cell anemia; in the middle-aged, spinal osteomyelitis may be associated with urinary bladder infection.