osteomyelitis, infection of bone tissue. The condition is most commonly caused by the infectious organism Staphylococcus aureus, which reaches the bone via the bloodstream or by extension from a local injury; inflammation follows with destruction of the cancellous (porous) bone and bone marrow, loss of blood supply, and bone death. Living bone grows around the infected area and walls in the dead tissue, forming an involucrum, the contents of which are gradually resorbed as the lesion is repaired.
Symptoms of osteomyelitis include fever, chills, and bone pain; later, swelling and redness may develop around the area of infection. Diagnosis is confirmed by radionuclide bone scans. Biopsy or bone aspiration may be used to determine the precise cause of the infection.
Treatment of osteomyelitis typically requires the long-term administration of intravenous antibiotics; some patients also require surgery to remove dead bone tissue. If the disease is not treated appropriately, acute osteomyelitis can progress to a chronic disease. In chronic osteomyelitis, infection remains active, and periodic drainage to the surface via sinus tracts may occur. Bone damage may be extensive, leading to increased susceptibility to fractures, stunted growth in children, and, in severe cases, amputation of the affected limb.
Osteomyelitis may occur as a complication of many diseases, such as typhoid, syphilis, tuberculosis, or sickle cell anemia. In middle-aged individuals, spinal osteomyelitis may be associated with urinary bladder infection. Intravenous drug use may also cause osteomyelitis.