Also Known As
AS
Rheumatoid Spondylitis
This article was last reviewed on
This article waslast modified on
October 10, 2017.
What is ankylosing spondylitis?

Ankylosing spondylitis is a form of arthritis that affects the spine and is a chronic condition. The term is derived from two Greek words that mean "bent spine inflammation." It causes painful inflammation of the joints between the vertebrae in the spine and between the spine and pelvis. In advanced cases, it can cause the vertebrae to fuse together, further limiting movement and resulting in a hunched over posture. Occasionally it can involve other joints or organs in the body as well.

Ankylosing spondylitis affects men more than women and is usually diagnosed during the teenage years, twenties, or thirties. People with a gene called HLA-B27 are at significantly increased risk of developing the condition. However, being born with this gene doesn't necessarily lead to ankylosing spondylitis and scientists are currently researching other suspected triggers.

Accordion Title
About Ankylosing Spondylitis
  • Signs and Symptoms

    Early symptoms of ankylosing spondylitis include pain and stiffness in the lower back and hips that may start in late adolescence or early adulthood. This pain and stiffness may fluctuate over time and spread to other parts of the body. In about 40% of those with ankylosing spondylitis, the eyes are affected with an inflammation called uveitis that can cause eye pain, sensitivity to light, and blurred vision. Other complications can include cardiac dysfunction and pulmonary disease. 

    It is believed that ankylosing spondylitis is an autoimmune disease. A trigger such as an infection may cause the body to react abnormally, leading to inflammation. Over time, inflammation of the ligaments around the bone can lead to new bone growth, which can cause separate vertebrae to fuse together (termed ankylosis). This can lead to long-term lack of mobility as well as stiffening of the rib cage, causing restricted chest expansion, reduced lung capacity, and difficulty breathing.

  • Tests

    Diagnosis of ankylosing spondylitis is usually based on signs and symptoms, but laboratory tests and imaging tests may also be used, including:

    • C-reactive protein (CRP) – to check for the presence of inflammation
    • Erythrocyte sedimentation rate (ESR) – another test for inflammation
    • Complete blood count (CBC) – to check for anemia, a complication of the chronic inflammation associated with ankylosing spondylitis, and increased numbers of white blood cells as a marker of inflammation
    • HLA-B27 – to determine if someone has this human leukocyte antigen on their cells, which significantly increases the risk of developing ankylosing spondylitis
    • X-rays or other imaging tests – to look for changes in the joints and bones, although it may take several years before characteristic degenerative changes are visible


    Early diagnosis allows for interventions that may help to prevent or delay complications of the condition.

  • Treatment

    Although there is no cure for ankylosing spondylitis, exercise and physical therapy can help prevent joint stiffness and certain medications can relieve pain and inflammation. These include non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen, and indomethacin. Other treatments include disease-modifying antirheumatic drugs (DMARDs) such as methotrexate or sulfasalazine, and corticosteroids like prednisone. Newer drugs include adalimumab, etanercept, infliximab, and golimumab, which are tumor necrosis factor (TNF) blockers. All of these drugs, however, are associated with side-effects and treatment options should be carefully reviewed with your health care provider.

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

MayoClinic.com. Ankylosing spondylitis. Available online at http://www.mayoclinic.com/health/ankylosing-spondylitis/DS00483 through http://www.mayoclinic.com. Accessed June 2013.

MedlinePlus Medical Encyclopedia. Ankylosing Spondylitis. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000420.htm. Accessed June 2013.

Genetics Home Reference. Ankylosing spondylitis. Available online at http://ghr.nlm.nih.gov/condition/ankylosing-spondylitis through http://ghr.nlm.nih.gov. Accessed June 2013.

Spondylitis Association of America. About Ankylosing Spondylitis. Available online at http://www.spondylitis.org/about/as.aspx through http://www.spondylitis.org. Accessed June 2013.

Momeni, M. et al. Cardiopulmonary Manifestations of Ankylosing Spondylitis. International Journal of Rheumatology, Volume 2011 (2011). Available online at http://www.hindawi.com/journals/ijr/2011/728471/ through http://www.hindawi.com. Accessed July 2013.

Sources Used in Previous Reviews

MedlinePlus. Ankylosing Sponylitis. Available online at http://www.nlm.nih.gov/medlineplus/ankylosingspondylitis.html. Accessed September 2010.

MayoClinic.com. Ankylosing spondylitis. Available online at http://www.mayoclinic.com/print/ankylosing-spondylitis/DS00483/DSECTION=all&METHOD=print through http://www.mayoclinic.com. Accessed September 17, 2010.

Wilfred CG Peh. Ankylosing Spondylitis. eMedicine: Radiology. Last updated March 25, 2009. Available online at http://emedicine.medscape.com/article/386639-overview through http://emedicine.medscape.com. Accessed Sept 2010.

AllAboutBackandNeckPain.com. Ankylosing Spondylitis. Available online at http://www.allaboutbackandneckpain.com/understand/ankylosing-spondylitis.asp through http://www.allaboutbackandneckpain.com. Accessed Sept 2010.