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Ankylosing Spondylitis


Lower back pain that may be intermittent or persistent. Pain may be worse at night.

Morning stiffness in the back or hips that improves with activity.

Limited chest capacity due to pain and stiffness in the ribs.

Neck or chest pain.

Eye pain, blurred vision, watery eyes, and aversion to light (due to associated uveitis).

Pain in the peripheral joints.

When To Call Your Doctor

Make an appointment with a doctor for any persistent back pain.

What Is It?

Ankylosing spondylitis (AS) is an uncommon type of inflammatory arthritis that primarily affects the joints of the spinal column. Typically, AS originates in the sacroiliac joints, where the vertebrae of the spine meet the pelvis. The disease tends to progress from the lower back up to the vertebrae in the neck. (Peripheral joints are also involved in as many as 25 percent of cases, especially among women.) Cartilage and other tissue between the joints gradually deteriorate and are replaced by hard, fibrous tissue. Eventually the bones fuse together and joint flexibility is lost. Symptoms—primarily lower back pain and stiffness—often first appear in late adolescence or early adulthood; onset after age 45 is very rare. Early onset of the disease is associated with a worse prognosis.

The most serious complication is spinal fracture that can result in quadriplegia; however, most patients suffer no serious disability despite the pain and are able to continue working. The disease may get progressively worse, stabilize, or go into remission at any point. About 25 to 30 percent of AS patients are affected by inflammation and scarring of structures within the eye, and a few patients may develop an abnormality of the aortic valve in the heart or scarring of lung tissue. Ankylosing spondylitis is more common among whites than other races and is three times more prevalent in men than women.

What Causes It?

o The cause of AS is unknown, though hereditary factors appear to play a role. There is also evidence suggesting a link between intestinal bacteria or inflammation and the autoimmune activity (in which the body's defenses against disease attack healthy tissue) involved in the mechanism of joint deterioration.


There is no known way to prevent AS.


No definitive laboratory tests exist to distinguish AS from similar inflammatory diseases. Diagnosis is primarily based on patient history, physical examination, and x-ray findings.

Blood tests may detect a specific antigen (HLA-B27) that is present in 90 percent of patients with AS. The presence of this antigen does not confirm the diagnosis (it is also seen in 6 to 8 percent of normal whites), but does suggest a genetic predisposition to the disease.

X-rays may reveal signs of joint deterioration in the spine, pelvis, or hips.

How To Treat It

There is no specific way to treat AS; therapy is aimed at relieving discomfort and maintaining joint function.

Nonsteroidal anti-inflammatory drugs (NSAIDs), especially indomethacin, are commonly prescribed to ease pain and inflammation.

Strength-training exercises and other forms of physical therapy may help to maintain or improve flexibility.

Braces and supports are not helpful and are not advised.

Occasionally, direct injections of corticosteroids may be beneficial in patients unresponsive to NSAIDs.

Severe arthritis in the hips may warrant total hip replacement surgery (arthroplasty).

If uveitis occurs, it can be treated with corticosteroids and medicated eyedrops.


From Johns Hopkins Symptoms and Remedies, the complete home medical reference. You can order this book now on our secure server.



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