In general, microorganisms may infect bone through one or more of three basic methods * Via the bloodstream (haematogeneously) – the most common method * From nearby areas of infection (as in cellulitis), or * Penetrating trauma, including iatrogenic causes such as joint replacements or internal fixation of fractures or secondary periapical periodontitis in teeth. The area usually affected when the infection is contracted through the bloodstream is the metaphysis of the bone. 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. Often, the body will try to create new bone around the area of necrosis. The resulting new bone is often called an involucrum. On histologic examination, these areas of necrotic bone are the basis for distinguishing between acute osteomyelitis and chronic osteomyelitis. Osteomyelitis is an infective process that encompasses all of the bone (osseous) components, including the bone marrow. When it is chronic, it can lead to bone sclerosis and deformity. Chronic osteomyelitis may be due to the presence of intracellular bacteria. Once intracellular, the bacteria are able to spread to adjacent bone cells. At this point, the bacteria may be resistant to certain antibiotics. These combined factors may explain the chronicity and difficult eradication of this disease, resulting in significant costs and disability, potentially leading to amputation. The presence of intracellular bacteria in chronic osteomyelitis is likely an unrecognized contributing factor in its persistence. In infants, the infection can spread to a joint and cause arthritis. In children, large subperiosteal abscesses can form because the periosteum is loosely attached to the surface of the bone. Because of the particulars of their blood supply, the tibia, femur, humerus, vertebrae, maxilla and the mandibular bodies are especially susceptible to osteomyelitis. Abscesses of any bone, however, 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 patients with sickle cell disease, the most common causative agent is Salmonella, with a relative incidence more than twice that of S. aureus.
complications of Melioidosis
complications of Bronchiolitis
complications of Asbestosis
complications of Tonsillitis
complications of Chagas disease
symptom of Cryptococcosis
complications of Idiopathic pulmonary fibrosis
complications of Diphtheria