Patient Articles

Ankylosing Spondylitis (AS)

What Is Ankylosing Spondylitis?

Ankylosing spondylitis (AS) causes ongoing (chronic) inflammation in your spinal column and sacroiliac joints. In many people, AS also causes health problems in other parts of the body.

What Causes Ankylosing Spondylitis?

More men than women get AS, usually between their teenage years and age 40. Nobody knows exactly what causes AS. Most researchers think that AS is an autoimmune disease. In autoimmune diseases, the body’s immune system is confused. It cannot tell the difference between your own body cells and invading organisms like viruses or bacteria. Therefore, it attacks some of the healthy cells in your body, and you get inflammation and feel pain.

Most people with AS have a gene called HLA-B27. However, having this gene does not mean that you will definitely develop AS. Even when parents who have AS pass the HLA-B27 gene along to their children, there is only a very small ( less than 20%) chance that the children will have problems with AS.

What Are the Symptoms?

Common first symptoms are
Stiffness and pain in the lower back and buttocks (which is usually worse when waking up in the morning or after being inactive for a while)

Other symptoms include

  • Inflammation and pain at the sites where tendons and ligaments insert into bones (for example in your feet)
  • Swelling of fingers and toes
  • Arthritis in the hip, knee, and shoulder joints
  • Pain in the spinal column and ribs
  • Inflammation and pain in the eyes (called uveitis) that may make them sensitive to light

If the disease is not treated properly, it also may cause

  • Stiff spine that cannot move anymore
  • A stooped posture
  • Difficulty with breathing, because the chest cannot expand properly
  • Bloating, gas, diarrhea, and other problems, due to inflammation in the digestive tract
  • How Is Ankylosing Spondylitis Diagnosed?

There is no one test for AS. Instead, your doctor will consider at a number of factors to make a diagnosis. Important factors include your medical history, a physical exam, X-rays, and lab results. Sometimes, your doctor may also order a test for the HLA-B27 gene.

What Is the Treatment?

The first line of treatment will include nonsteroidal anti inflammatory medications. For some patients these medications may provide adequate relief. Physicians will also advise patients to learn a regular exercise and stretching program, often with the help of a physical therapist. It is important to continue exercise for the long term.

New medicines called biologics are available that control the symptoms of people with AS very well. These include:

  • Enbrel® (etanercept)
  • Remicade® (infliximab)
  • Humira® (adalimumab)
  • Symponi® (golimumab)

For more information about non steroidal anti-inflammatory drugs and biologics please see the Rheumatology Information articles on these topics.


Ankylosing Spondylitis Resources

Find out more about AS online at the Spondylitis Association of America
American College of Rheumatology