Learn about this inflammatory disease that can cause some of the vertebrae in the spine to fuse over time.
Ankylosing spondylitis, also known as axial spondyloarthritis, is an inflammatory disease that, over time, can cause some of the bones in the spine, called vertebrae, to fuse. This fusing makes the spine less flexible and can result in a hunched posture. If ribs are affected, it can be difficult to breathe deeply.
Axial spondyloarthritis has two types. When the condition is found on X-ray, it is called ankylosing spondylitis, also known as axial spondyloarthritis. When the condition can't be seen on X-ray but is found based on symptoms, blood tests and other imaging tests, it is called nonradiographic axial spondyloarthritis.
Symptoms typically begin in early adulthood. Inflammation also can occur in other parts of the body — most commonly, the eyes.
There is no cure for ankylosing spondylitis, but treatments can lessen symptoms and possibly slow progression of the disease.
As ankylosing spondylitis worsens, new bone forms as part of the body's attempt to heal. The new bone gradually bridges the gaps between vertebrae and eventually fuses sections of vertebrae together. Fused vertebrae can flatten the natural curves of the spine, which causes an inflexible, hunched posture.
Early symptoms of ankylosing spondylitis might include back pain and stiffness in the lower back and hips, especially in the morning and after periods of inactivity. Neck pain and fatigue also are common. Over time, symptoms might worsen, improve or stop at irregular intervals.
The areas most commonly affected are:
Seek medical attention if you have low back or buttock pain that came on slowly, is worse in the morning or awakens you from your sleep in the second half of the night — particularly if this pain improves with exercise and worsens with rest. See an eye specialist immediately if you develop a painful red eye, severe light sensitivity or blurred vision.
Ankylosing spondylitis has no known specific cause, though genetic factors seem to be involved. In particular, people who have a gene called HLA-B27 are at a greatly increased risk of developing ankylosing spondylitis. However, only some people with the gene develop the condition.
Onset generally occurs in late adolescence or early adulthood. Most people who have ankylosing spondylitis have the HLA-B27 gene. But many people who have this gene never develop ankylosing spondylitis.
In severe ankylosing spondylitis, new bone forms as part of the body's attempt to heal. This new bone gradually bridges the gap between vertebrae and eventually fuses sections of vertebrae. Those parts of the spine become stiff and inflexible. Fusion also can stiffen the rib cage, restricting lung capacity and function.
Other complications might include:
During the physical exam, your health care provider might ask you to bend in different directions to test the range of motion in your spine. Your provider might try to reproduce your pain by pressing on specific portions of your pelvis or by moving your legs into a particular position. You also may be asked to take a deep breath to see if you have difficulty expanding your chest.
X-rays allow doctors to check for changes in joints and bones, also called radiographic axial spondyloarthritis, though the visible signs of ankylosing spondylitis, also called axial spondyloarthritis, might not be evident early in the disease.
MRI uses radio waves and a strong magnetic field to provide more-detailed images of bones and soft tissues. MRI scans can reveal evidence of nonradiographic axial spondyloarthritis earlier in the disease process, but they are much more expensive.
There are no specific lab tests to identify ankylosing spondylitis. Certain blood tests can check for markers of inflammation, but many different health problems can cause inflammation.
Blood can be tested for the HLA-B27 gene. But many people who have the gene don't have ankylosing spondylitis, and people can have the disease without having the HLA-B27 gene.
The goal of treatment is to relieve pain and stiffness and prevent or delay complications and spinal deformity. Ankylosing spondylitis treatment is most successful before the disease causes irreversible damage.
Nonsteroidal anti-inflammatory drugs (NSAIDs) — such as naproxen sodium (Aleve) and ibuprofen (Advil, Motrin IB, others) — are the medicines health care providers most commonly use to treat axial spondyloarthritis and nonradiographic axial spondyloarthritis. These medicines can relieve inflammation, pain and stiffness, but they also might cause gastrointestinal bleeding.
If NSAIDs aren't helpful, your doctor might suggest starting a tumor necrosis factor (TNF) blocker or an interleukin-17 (IL-17) inhibitor. These medicines are injected under the skin or through an intravenous line. Another option is a Janus kinase (JAK) inhibitor. JAK inhibitors are taken by mouth. These types of medicines can reactivate untreated tuberculosis and make you more prone to infections.
Examples of TNF blockers include:
IL-17 inhibitors used to treat ankylosing spondylitis include secukinumab (Cosentyx) and ixekizumab (Taltz). JAK inhibitors available to treat ankylosing spondylitis include tofacitinib (Xeljanz) and upadacitinib (Rinvoq).
Physical therapy is an important part of treatment and can provide a number of benefits, from pain relief to improved strength and flexibility. A physical therapist can design specific exercises for your needs. To help preserve good posture, you may be taught:
Most people with ankylosing spondylitis or nonradiographic axial spondyloarthritis don't need surgery. Surgery may be recommended if you have severe pain or if a hip joint is so damaged that it needs to be replaced.
Lifestyle choices also can help manage ankylosing spondylitis.
The course of your condition can change over time, and you might have painful episodes and periods of less pain throughout your life. But most people are able to live productive lives despite a diagnosis of ankylosing spondylitis.
You might want to join an online or in-person support group of people with this condition, to share experiences and support.
You might first bring your symptoms to the attention of your family health care provider. Your provider may refer you to a specialist in inflammatory disorders called a rheumatologist.
Here's some information to help you get ready for your appointment.
Make a list of:
Take a family member or friend along, if possible, to help you remember the information you're given.
For ankylosing spondylitis, basic questions to ask your health care team include:
Your doctor is likely to ask you questions, such as: