Understanding Ankylosing Spondylitis and the Latest Treatments

M.A., Health Writer
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Ankylosing spondylitis (AS) is a form of arthritis affecting the spine and pelvis, particularly in the joint where the sacrum, the very last spinal vertebra, joins the ilium or pelvic bone. The disease may also affect the ribcage, hips, knees, tendon insertions, and less commonly, eyes and bowel, according to Michael M. Ward, M.D., Master of Public Health, of the Intramural Research Program at the National Institute of Arthritis and Musculoskeletal and Skin Diseases. HealthCentral spoke to Dr. Ward in a telephone interview.


x-ray, pelvis, hips, pelvic

Numbers aren't increasing

Ankylosing spondylitis, a form of chronic inflammatory arthritis, occurs in half a percent (0.5 percent) of the population, says Dr. Ward. "There's been no major change in incidence of this disease because it is primarily determined by genetics. Many people with signs and symptoms consistent with AS, in spite of many years, haven't yet shown bone changes necessary to confirm an AS diagnosis." The condition is usually diagnosed by analyzing changes in the spine and pelvis on an X-ray.


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Not completely understood

Most people with AS have lifelong symptoms and some degree of spinal fusion. "A very small percentage may progress with AS and then just stop," says Dr. Ward. Others have symptoms but no advanced changes on X-ray. "We don't totally understand since they have symptoms but that's all we see — it's the same disease or a disease that mimics AS. Newer genetic research suggests a 'genetic signature' to AS, but the more we delve into it, the murkier it can appear to be. There is more work to be done."


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How to treat ankylosing spondylitis

The first lines of treatment for AS are physical therapy and exercise. Unlike some types of inflammatory arthritis, pain and stiffness of AS often improves with movement, Dr. Ward says. "People feel better when they're up and active. But if someone has a desk job, they can have symptoms of AS after sitting for two to three hours, so we encourage them to get up and move. Some people are awakened at night by symptoms, so they get up and walk around for 20 minutes and the pain subsides."


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Get moving to help yourself

The importance of movement or exercise can't be stressed enough, Dr. Ward says. "Getting into the habit if you have AS controls not only symptoms, but may help slow the rate of bony fusion, when two or more individual vertebrae in the joints grow together. When that happens, that segment of bone moves as one unit instead of two. This leads to inflexibility, and is not reversible. About that movement: Remember a pond or lake freezes faster in winter than a river."


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The basics work for many

Physical therapy is not to be done "forever." "It is thorough instruction on how to move properly, with an emphasis on active motions rather than passive interventions," Dr. Ward says. "Don't go to physical therapy just to get a massage, but to learn how to move properly and to exercise correctly in several sessions. The second-most-traditional treatment, often combined with movement, is non-steroidal anti-inflammatory drugs (NSAIDs) such as naproxen sodium or ibuprofen, to reduce inflammation."


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How to manage fusion

If a fusion occurs, in order to retain flexibility, think about and use proper posture, says Dr. Ward. "You want fusion to occur in an upright position, not a 'bent-down' position. People learn to accommodate their limitation with workarounds, as it evolves slowly over decades. The neck, versus the low back for example, has the greatest functional problems and can cause trouble when driving. Fusion in the thoracic spine can cause limitations in breathing capacity and impair aerobic activity."


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The logic of biologics

Since the early 2000s, biologics or biologic response modifiers have improved treatment for people not well controlled on NSAIDS or with exercise, says Dr. Ward. Biologics block action of proteins the body produces during an inflammatory response. Tumor necrosis factor (TNF) inhibitors are most commonly used for AS, usually etanercept, adalimumab, infliximab, certolizumab, and golimumab. TNF's interfere with the inflammation resulting from the actions of the chemical tumor necrosis factor alpha.


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Use biologics carefully

"Not everyone needs a biologic, and we are always concerned about side effects," Dr. Ward says. "We must weigh potential risks against benefits, including the possibility of serious infections that could be fatal. Take sensible precautions: A person with an infection shouldn't take biologics — tuberculosis or a chronic lung infection must be treated before they start a biologic. If they develop an infection during treatment, treatment should be interrupted until the infection is resolved."


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Interleukin-17 inhibitors

Another useful class of drugs includes interleukin-17 or IL-17 inhibitors, says Dr. Ward. A U.S. Food Drug Administration (FDA)-approved medication in that class is secukinumab or AIN457. Its action blocks IL-17, a cytokine or cell-messenger molecule comprised of protein, thereby reducing inflammation. Similar medications in the IL-17 family used for related conditions such as psoriasis have been tested on AS but are not FDA-approved. An oral Janus kinase (JAK) inhibitor, tofacitinib, has shown promising results in a trial.


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More trust in the gut

"The gut microbiome is also a major area of interest," Dr. Ward says. "Research is centered on how potential alterations in the microbiome could influence inflammation and symptoms of ankylosing spondylitis." In fact, a 2016 comprehensive analysis of literature underscored the role of gut microbiome in chronic inflammation of AS and its possible underlying mechanisms. A separate 2017 study found that alterations of the gut microbiome are associated with development of AS.


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The role of surgery

Surgery is used infrequently, and is not normally utilized for the spine or sacroiliac joints, Dr. Ward says. "No surgery can stop disease progression. Approximately 10 to 15 percent of people have hip arthritis severe enough to lead to hip replacement as a long-term consequence. Very rarely people happen to fuse downward with that bent-over posture, and there is a very extensive spinal corrective procedure that can be done for that — but it's generally not an option."