Osteonecrosis: From 1 Different Sources
n. death of bony tissue, usually adjacent to a joint surface where it is enclosed by avascular cartilage. It is usually caused by loss of blood supply (avascular necrosis) due to trauma and is a definitive feature in a variety of conditions, including *Legg-Calvé-Perthes disease, *sickle-cell disease, *Gaucher’s disease, epiphyseal infection and fractures, alcohol abuse, and high-dosage corticosteroids. Sites that are particularly susceptible include the head of the femur, the scaphoid and lunate bones of the wrist, the *capitulum of the humerus, and the talus and navicular bones of the ankle. In its earliest stages there is localized pain without any changes visible on X-ray examination; a *bone scan or MRI will assist with diagnosis.
see osteonecrosis.... avascular necrosis
n. a *monoclonal antibody that interferes with the growth of new blood vessels (see angiogenesis) by inhibiting the action of *vascular endothelial growth factor. It is licensed for the treatment of metastatic colorectal cancer, breast cancer, ovarian cancer, cervical cancer, and non-small-cell lung cancer. Side-effects include hypertension, bowel perforation, and bleeding; there may be a risk of osteonecrosis of the jaw.... bevacizumab
pl. n. a class of drugs that inhibit the resorption of bone by blocking the action of *osteoclasts. This property makes them useful for treating certain bone disorders, such as Paget’s disease and osteoporosis, as well as malignant disease – both in terms of pain relief and in treating hypercalcaemia due to cancer. There is a risk of *osteonecrosis of the jaw in patients receiving bisphosphonates for cancer. This risk is increased by tooth extraction. Bisphosphonates include *alendronic acid, etidronate, *pamidronate disodium, risedronate, clodronate, and *zoledronic acid.... bisphosphonates
an imaging investigation of a patient’s bone using radioactive *tracers. *Technetium-99m phosphate is injected intravenously and absorbed into the hydroxyapatite crystals of bone. It concentrates in areas of increased blood flow and metabolism, such as areas of infection, trauma, and *neoplasia, and gives off radiation that can be detected by a *gamma camera, thereby producing a map or scan of activity in the target area. A bone scan is particularly useful in the diagnosis of subtle fractures (including stress fractures), avascular necrosis (see osteonecrosis), osteomyelitis, tumour spread (metastasis), and loosening of orthopaedic implants.... bone scan
(caisson disease) a syndrome occurring in people working under high pressure in diving bells or at great depths with breathing apparatus. On return to normal atmospheric pressure nitrogen dissolved in the bloodstream expands to form bubbles, causing pain (the bends) and blocking the circulation in small blood vessels in the brain and elsewhere (decompression sickness). Pain, paralysis, and other features may be eliminated by returning the victim to a higher atmospheric pressure and reducing this gradually, so causing the bubbles to redissolve. Chronic compressed air illness may cause damage to the bones (see osteonecrosis), heart, and lungs.... compressed air illness
a technique for exposing a patient to oxygen at a pressure of greater than 1 atmosphere in a compression chamber. It is used to treat carbon monoxide poisoning, gas gangrene, compressed air illness, and acute breathing difficulties. It is also used in some cases during heart surgery. In dental extractions and implant treatment it may reduce the incidence of osteonecrosis in patients who have received radiation to the head and neck region (osteoradionecrosis).... hyperbaric oxygenation
necrosis of the *lunate bone of the wrist caused by interruption of its blood supply (see osteochondritis; osteonecrosis). It usually follows chronic stress or injury to the wrist and presents with pain and stiffness, with reduced grip strength. Initially, X-rays may show no abnormality; if the disease is suspected, a bone scan or MRI is indicated. Treatment is with rest, splintage, and *NSAIDs, but some cases require surgical shortening of the radius or *arthrodesis of the wrist. [R. Kienböck (1871–1953), Austrian radiologist]... kienböck’s disease
osteonecrosis of the *navicular bone of the foot (see osteochondritis). It occurs in children aged 3–7 years, causing pain and limping, and is treated by strapping the foot, rest, and anti-inflammatory drugs. [A. Köhler (1874–1947), German physician]... köhler’s disease
(oste-, osteo-) combining form denoting bone. Examples: ostalgia (pain in); osteocarcinoma (carcinoma of); osteonecrosis (death of); osteoplasty (plastic surgery of).... ost
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