Ankylosing spondylitis is an inflammatory disease that can cause some of the vertebrae in your spine to fuse together. This fusing makes the spine less flexible and can result in a hunched-forward posture. If ribs are affected, it may be difficult to breathe deeply.
Ankylosing spondylitis affects men more often than women. Signs and symptoms of ankylosing spondylitis typically begin in early adulthood. Inflammation also can occur in other parts of your body — most commonly, your eyes.
There is no cure for ankylosing spondylitis, but treatments can decrease your pain and lessen your symptoms.
Early signs and symptoms of ankylosing spondylitis may include pain and stiffness in your lower back and hips, especially in the morning and after periods of inactivity. Over time, symptoms may worsen, improve or stop completely at irregular intervals.
The areas most commonly affected are:
The joint between the base of your spine and your pelvis
The vertebrae in your lower back
The places where your tendons and ligaments attach to bones, mainly in your spine, but sometimes along the back of your heel
The cartilage between your breastbone and ribs
Your hip and shoulder joints
When to see a doctor
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 (ophthalmologist) 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 significantly increased risk of developing ankylosing spondylitis.
Your sex. Men are more likely to develop ankylosing spondylitis than are women.
Your age. Onset generally occurs in late adolescence or early adulthood.
Your heredity. Most people who have ankylosing spondylitis have the HLA-B27 gene. But many people who have this gene never develop ankylosing spondylitis.
In severe cases of 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 together. Those parts of your spine become stiff and inflexible. Fusion can also stiffen your rib cage, restricting your lung capacity and function.
Other complications may include:
Eye inflammation (uveitis). One of the most common complications of ankylosing spondylitis, uveitis can cause rapid-onset eye pain, sensitivity to light and blurred vision. See your doctor right away if you develop these symptoms.
Compression fractures. Some people experience a thinning of their bones during the early stages of ankylosing spondylitis. Weakened vertebrae may crumble, increasing the severity of your stooped posture. Vertebral fractures sometimes can damage the spinal cord and the nerves that pass through the spine.
Heart problems. Ankylosing spondylitis can cause problems with your aorta, the largest artery in your body. The inflamed aorta can enlarge to the point that it distorts the shape of the aortic valve in the heart, which impairs its function.
During the physical exam, your doctor may ask you to bend your back in different directions. He or she may also measure your chest circumference — once with your lungs empty and once with them full of air — to compare the difference.
Your doctor may also try to reproduce your pain by pressing on specific portions of your pelvis or by moving your legs into a particular position. He or she might also ask you to try to stand upright, with your heels and the back of your head against a wall.
X-rays allow your doctor to check for changes in your joints and bones, though the visible signs of ankylosing spondylitis may not be evident early in the disease.
Magnetic resonance imaging (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 ankylosing spondylitis earlier in the disease process, but are much more expensive.
There are no specific lab tests to identify ankylosing spondylitis. Certain blood tests can check for markers of inflammation, but inflammation can be caused by many different health problems. Your blood can be tested for the HLA-B27 gene, but most people who have that gene don't have ankylosing spondylitis.
The goal of treatment is to relieve your pain and stiffness, and prevent or delay complications and spinal deformity. Ankylosing spondylitis treatment is most successful before the disease causes irreversible damage to your joints.
Nonsteroidal anti-inflammatory drugs (NSAIDs) — such as naproxen (Naprosyn) and indomethacin (Indocin) — are the medications doctors most commonly use to treat ankylosing spondylitis. They can relieve your inflammation, pain and stiffness. However, these medications also can cause gastrointestinal bleeding.
If NSAIDs aren't helpful, your doctor may suggest tumor necrosis factor (TNF) blockers. TNF is a cell protein that acts as an inflammatory agent in rheumatoid arthritis. TNF blockers target this protein to help reduce pain, stiffness, and tender or swollen joints. They are administered by injecting the medication under the skin or through an intravenous line.
Examples of TNF blockers include:
TNF blockers can reactivate latent tuberculosis and may cause certain neurological problems.
Physical therapy can provide a number of benefits, from pain relief to improved physical strength and flexibility. Your doctor may recommend that you meet with a physical therapist to provide you with specific exercises designed for your needs.
Range-of-motion and stretching exercises can help maintain flexibility in your joints and preserve good posture. Proper sleep and walking positions and abdominal and back exercises can help maintain your upright posture.
Most people with ankylosing spondylitis don't need surgery. However, your doctor may recommend surgery if you have severe pain or joint damage, or if your hip joint is so damaged that it needs to be replaced.
If you smoke, quit. Smoking is generally bad for your health, but it creates additional problems for people with ankylosing spondylitis. Depending on the severity of your condition, ankylosing spondylitis can affect the mobility of your rib cage. Damaging your lungs by smoking can further compromise your ability to breathe.
The course of your condition may change over time, and you may experience relapses and remissions throughout your life. But most people are able to live productive lives despite a diagnosis of ankylosing spondylitis.
You may want to join an online or in-person support group of people with this condition, to share experiences and support.