Ankylosing spondylitis

Although ankylosing spondylitis (AS) can affect more than one person in a family, it is not a purely genetic disease. While genes seem to play a role, the exact cause of AS is not known. It is considered to be multifactorial, which means that multiple genetic and environmental factors likely interact to affect a person's risk to develop AS. Most of these factors have not been identified. Inheriting a genetic variation that has been associated with AS does not mean a person will develop AS. Currently, it is not possible to predict the exact likelihood that the children of an affected person will develop the disease.

You can find more information about the genetics of AS from Genetics Home Reference, the U.S National Library of Medicine's Web site for consumer information about genetic conditions and the genes or chromosomes related to those conditions.

The long-term outlook for people with ankylosing spondylitis varies and is hard to predict. In many cases, at the onset of the disease, symptoms are not constant and are limited to one side of the body. As the disease progresses, pain and stiffness generally become more severe and more regular. Some people have few, if any, symptoms, while others develop chronic progressive disease and disability due to spinal inflammation leading to fusion. Most people with mild disease that is restricted to a small area of involvement are able to maintain almost full functional capacity. Most functional loss in affected people occurs during the first 10 years of illness. Approximately 1% (1 in 100) of affected people develop a stage of "burn-out" of disease activity and enter long-term remission.

A minority of people develop life-threatening complications related to other body systems. Rarely, people may have problems related to an abnormal heart rhythm or the aortic heart valve; scarring or thickening of lung tissue; or inflammation in the large intestine (colitis).

A number of factors that affect disease severity and prognosis have been identified. For example, there may be a more severe outcome if the hip is involved; if there is a poor response to NSAIDs; if there is a young age of onset; and/or if there is limited range of motion of the lumbar spine. Other factors associated with a poor outcome include cigarette smoking; increasing severity seen on imaging studies; presence of other related diseases (e.g., psoriasis or inflammatory bowel disease); being male; and various findings on laboratory tests.

The main goal of treatment for people with ankylosing spondylitis (AS) is to maximize long-term quality of life. This may involve easing symptoms of pain and stiffness; retaining function; preventing complications (such as contractures); and minimizing the effects of associated conditions.

Education, exercise, and medications are all very important in managing AS. An exercise program is recommended for all affected people, and some may need individual physical therapy. Affected people are encouraged to speak with their health care provider before instituting any changes to an exercise regime. Video demonstrations of exercises tailored for ankylosing spondylitis are available for viewing through the National Ankylosing Spondylitis Society in the UK.

Medications may include nonsteroidal anti-inflammatory drugs (NSAIDs); pain relievers; sulfasalazine; and anti-tumor necrosis factor drugs. Steroid injections may be helpful for some people. Most people don't need surgery, but it may be indicated when there is severe, persistent pain or severe limitation in mobility and quality of life. Smoking creates additional problems for people with AS, so affected people who smoke should quit.

More detailed information about the treatment of ankylosing spondylitis is available on Medscape's Web site. You may need to register to view the article, but registration is free.