Ankylosing spondylitis

Ankylosing spondylitis, also called axial spondyloarthritis, is a type of inflammatory disease that mainly affects the spine. Over time, the inflammation can cause some of the bones in the spine, called vertebrae, to fuse together. This fusing makes the spine less flexible and can lead to a hunched posture. If the joints in the chest are affected, it may become harder to take deep breaths.

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 cannot be seen on X-ray but is found based on symptoms, blood tests and other imaging tests, such as an MRI, it is called nonradiographic axial spondyloarthritis.

Symptoms often begin in early adulthood. The condition also can cause inflammation in other parts of the body. This happens most often in the eyes, called uveitis.

There is no cure for ankylosing spondylitis, but treatments can lessen symptoms, manage pain and possibly slow down the progression of the disease.

Ankylosing spondylitis

As ankylosing spondylitis progresses, the body forms new bone in an effort to heal inflamed areas. 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 leads to stiffness and a hunched posture.

Early symptoms of ankylosing spondylitis might include back pain and stiffness, especially in the lower back and hips. These symptoms may be worse in the morning or after periods of inactivity. Neck pain and fatigue also are common. Other symptoms include vision changes or eye pain, skin rashes and stomach pain.

Symptoms can come and go over time. Some people have periods of increased pain and stiffness, followed by times when symptoms improve or go away for a while.

The most commonly affected areas are:

• The joints between the base of the spine and the pelvis, called sacroiliac joints.
• The vertebrae in the lower back.
• The places where tendons and ligaments attach to bones, mainly in the spine or along the back of the heel.
• The cartilage between the ribs and the breastbone.
• The hip and shoulder joints.

See a healthcare professional if you have low back or buttock pain that comes on slowly. Also see a healthcare professional if the pain feels worse in the morning or awakens you from your sleep at night, especially if this pain improves with exercise and worsens with rest. You also should seek care from an eye specialist right away if you develop a red, painful eye, light sensitivity or blurry vision since these can be signs of inflammation in the eye.

The exact cause of ankylosing spondylitis isn't known, but genetic factors seem to be involved. 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 and not everyone with ankylosing spondylitis has this gene.

Risk factors for ankylosing spondylitis include:

• Younger age. The disease usually starts in late adolescence or early adulthood.
• Genetics. Most people who have ankylosing spondylitis have the HLA-B27 gene. But many people who have this gene never develop ankylosing spondylitis.

In serious cases of ankylosing spondylitis, the body tries to heal the long-term inflammation by forming new bone. Over time, this new bone bridges the gaps between vertebrae and causes them to fuse together. The fused parts of the spine become stiff and less flexible. If the joints in the chest around the rib cage also become stiff, the stiffness can limit how much the lungs can expand and make deep breathing more difficult.

Other possible complications include:

• Eye inflammation, called uveitis. Uveitis is one of the most common complications of ankylosing spondylitis. It can cause sudden eye pain, redness, light sensitivity and blurry vision. See your healthcare professional right away if you develop these symptoms.
• Compression fractures. When the bones in the spine weaken, they can press together and make a hunched posture worse. Vertebral fractures also can press on and possibly damage the spinal cord and nerves.
• Heart issues. Ankylosing spondylitis can cause issues with the aorta. The aorta is the largest artery in the body. When the aorta gets inflamed, it can swell and change the shape of the aortic valve in the heart. This makes the valve leak, and it can't work as well. This is called aortic regurgitation. This inflammation also increases the overall risk of heart disease.