health care  
All about avascular necrosis causes of avascular necrosis risk factors for avascular necrosis symptoms of avascular necrosis diagnosis of avascular necrosis treatment for avascular necrosis

What causes avascular necrosis?

Avascular necrosis can be caused by trauma and damage to the blood vessels that supply bone its oxygen. Other causes of poor blood circulation to the bone include an embolism of air or fat that blocks the blood flow through the blood vessels, abnormally thick blood (hypercoagulable state), and inflammation of the bloodvessel walls (vasculitis). Four basic

mechanisms are implicated: mechanical disruption (e.g., broken hip), external pressure on or damage to a vessel wall (e.g., vasculitis, radiation therapy), arterial thrombosis or embolism (e.g., sickle cell diseases, prednisone, alcohol), and venous or blood outflow occlusion (e.g., infection). Although the relationship between the inciting event and the onset of osteonecrosis is clear in some cases, such as vascular disruption from a femoral neck fracture or arterial thrombosis from sickled blood cells, the inciting event in most cases is poorly understood. There is an increased incidence of osteonecrosis seen in people who chronically use corticosteroids, as well as people who consume more than 3 glasses of wine or 5 beers per week.

Many things can cause avascular necrosis. One of the most common causes is a fracture through the thigh bone which results in tearing of the blood vessels that nourish the femoral head. AVN can also occur without a fracture or other major injury. These same blood vessels can be blocked by blood clots (thrombi or emboli). They can also be blocked by fat droplets which form in the circulating blood, by clumps of abnormal red blood cells (as in sickle cell disease), and occasionally by nitrogen bubbles (which form in individuals such as deep sea divers who work under different atmospheric pressures). AVN can also result from inflammation or narrowing of the arteries, and from increased pressure outside the blood vessels. it is frequently seen with excess use of alcohol. A very small percentage of people who use corticosteroids for prolonged periods of time will also develop it. Why this is so is unclear. It may be that certain individuals are especially sensitive to steroids and form circulating fat droplets as a result. Although some authorities are of the opinion that the blood vessel changes in lupus itself can result in AVN, there are almost no cases of AVN reported in patients with lupus who have not been treated with steroids.

More information on avascular necrosis

What is avascular necrosis? - Avascular necrosis of bone (aseptic necrosis or osteonecrosis), is a disease that results from poor blood supply to an area of bone causing bone death.
What causes avascular necrosis? - Avascular necrosis can be caused by trauma and damage to the blood vessels that supply bone its oxygen. A common cause is a fracture through the thigh bone.
What're the risk factors for avascular necrosis? - Risk factors for avascular necrosis include injury, steroid medications, alcohol use, Gaucher's disease, pancreatitis, radiation treatments and chemotherapy.
What're the symptoms of avascular necrosis? - The period of time between the first symptoms of avascular necrosis and loss of joint function is different for each patient.
How is avascular necrosis diagnosed? - The doctor may use one or more imaging techniques to diagnose avascular necrosis. MRI is the most sensitive method for diagnosing avascular necrosis in the early stages.
What's the treatment for avascular necrosis? - Treatment for avascular necrosis include use of NSAIDs or other analgesics for pain, and avoidance of weight-bearing or strain on affected bones and joints.
Bone, joint, & muscle disorders

Topics in bone, joint, and muscle disorders

Bone diseases
Bone tumors
Bone cancer
Muscle diseases
Spine (neck and back) disorders
Dupuytren's contracture
Plantar fasciitis
Rheumatoid arthritis
Juvenile rheumatoid arthritis
Septic arthritis (infectious Arthritis)
Psoriatic arthritis
Reiter's syndrome (reactive arthritis)
Ankylosing spondylitis
Gout (gouty arthritis)

All information is intended for reference only. Please consult your physician for accurate medical advices and treatment. Copyright 2005,, all rights reserved. Last update: July 18, 2005