Osteomyelitis (OM) is an infection of bone. Symptoms may include pain in a specific bone with overlying redness, fever, and weakness. The long bones of the arms and legs are most commonly involved in children e.g. the femur and humerus, while the feet, spine, and hips are most commonly involved in adults.The cause is usually a bacterial infection, but rarely can be a fungal infection. It may occur by spread from the blood or from surrounding tissue. Risks for developing osteomyelitis include diabetes, intravenous drug use, prior removal of the spleen, and trauma to the area. Diagnosis is typically suspected based on symptoms and basic laboratory tests as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).This is because plain radiographs are unremarkable in the first few days following acute infection. Diagnosis is further confirmed by blood tests, medical imaging, or bone biopsy.Treatment of bacterial osteomyelitis often involves both antimicrobials and surgery. In people with poor blood flow, amputation may be required. Treatment of the relatively rare fungal osteomyelitis as mycetoma infections entails the use of antifungal medications. In contrast to bacterial osteomyelitis, amputation or large bony resections is more common in neglected fungal osteomyelitis, namely mycetoma, where infections of the foot account for the majority of cases. Treatment outcomes of bacterial osteomyelitis are generally good when the condition has only been present a short time. About 2.4 per 100,000 people are affected each year. The young and old are more commonly affected. Males are more commonly affected than females.
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. Diagnosis
The diagnosis of osteomyelitis is complex and relies on a combination of clinical suspicion and indirect laboratory markers such as a high white blood cell count and fever, although confirmation of clinical and laboratory suspicion with imaging is usually necessary.Radiographs and CT are the initial method of diagnosis, but are not sensitive and only moderately specific for the diagnosis. They can show the cortical destruction of advanced osteomyelitis, but can miss nascent or indolent diagnoses.Confirmation is most often by MRI. The presence of edema, diagnosed as increased signal on T2 sequences, is sensitive, but not specific, as edema can occur in reaction to adjacent cellulitis. Confirmation of bony marrow and cortical destruction by viewing the T1 sequences significantly increases specificity. The administration of intravenous gadolinium-based contrast enhances specificity further.