Read more about this disease, some with Classification – Types – Signs and symptoms – Genetics – Pathophysiology – Diagnosis – Screening – Prevention – Treatment and management – Cures and much more, some including pictures and video when available.
Osteomyelitis is an infection of bone or bone marrow, usually caused by pyogenic bacteria or mycobacteria.[1] It can be usefully subclassified on the basis of the causative organism, the route, duration and anatomic location of the infection.
Generally, microorganisms may infect bone through one or more of three basic methods: via the bloodstream, contiguously from local areas of infection (as in cellulitis), or penetrating trauma, including iatrogenic causes such as joint replacements or internal fixation of fractures or root-canaled teeth.[1] Once the bone is infected, leukocytes enter the infected area, and in their attempt to engulf the infectious organisms, release enzymes that lyse the bone. Pus spreads into the bone’s blood vessels, impairing their flow, and areas of devitalized infected bone, known as sequestra, form the basis of a chronic infection.[1] Often, the body will try to create new bone around the area of necrosis. The resulting new bone is often called an involucrum.[1] On histologic examination, these areas of necrotic bone are the basis for distinguishing between acute osteomyelitis and chronic osteomyelitis. Osteomyelitis is an infective process which encompasses all of the bone (osseous) components, including the bone marrow. When it is chronic it can lead to bone sclerosis and deformity.
In infants, the infection can spread to the joint and cause arthritis. In children, large subperiosteal abscesses can form because the periosteum is loosely attached to the surface of the bone.[1]
Because of the particulars of their blood supply, the tibia, femur, humerus, vertebra, the maxilla, and the mandibular bodies are especially susceptible to osteomyelitis.[2] However, abscesses of any bone may be precipitated by trauma to the affected area. Many infections are caused by Staphylococcus aureus, a member of the normal flora found on the skin and mucous membranes.
In children, the long bones are usually affected. In adults, the vertebrae and the pelvis are most commonly affected.
Acute osteomyelitis almost invariably occurs in children. When adults are affected, it may be because of compromised host resistance due to debilitation, intravenous drug abuse, infectious root-canaled teeth, or other disease or drugs (e.g. immunosuppressive therapy).
Osteomyelitis is a secondary complication in 1-3% of patients with pulmonary tuberculosis[1]. In this case, the bacteria generally spread to the bone through the circulatory system, first infecting the synovium (due to its higher oxygen concentration) before spreading to the adjacent bone[1]. In tubercular osteomyelitis, the long bones and vertebrae are the ones which tend to be affected[1].
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