Ankylosing spondylitis (AS) and the related conditions are quite variable and difficult to predict. They can cause a lot of pain, although treatment will help to ease this. You may have times when the symptoms become worse and other times when you find it easier to cope with the pain and stiffness. AS can make you feel generally unwell, lose weight or tire easily.
Most people with a spondyloarthritis have some stiffening in the spine, usually in the lower back. This can be painless and may not interfere with physical activity because the neck, hips, limbs and the upper part of your spine can remain quite mobile. However, if more of your spine stiffens or your knees or hips are affected, you may have more difficulty with mobility. Treatment can help prevent these mobility problems.
Very rarely, there may be complications affecting the heart, lungs and nervous system. The valves in the heart may leak, which can put it under more strain. And long-term inflammation and tissue scarring in the lungs can reduce rib movement, which means you can't take in a full breath. Very rarely, the top of the lungs may become scarred. Fewer than 1 in 100 people with ankylosing spondylitis have these problems, and they are even less common in other types of spondyloarthritis. Even so, if you smoke, it's extremely important to try to stop because smoking is likely to add to any heart or lung problems.
People with ankylosing spondylitis, especially those who've had the condition for a long time and whose vertebrae have fused, are at increased risk of spinal fractures following a trauma (for example, a fall or car accident). Spinal fractures can cause nerve damage, so it's important to tell any doctor treating you following trauma that you have ankylosing spondylitis, especially if you have new unexplained pain in your spine or new weakness or tingling in your arms or legs. The fracture may not show easily on x-rays, so you may need a magnetic resonance imaging (MRI) or computed tomography (CT) scan.
Some people with ankylosing spondylitis develop osteoporosis (thinning of the bones), and it's important that this is treated. Your doctor may suggest you have a bone density (DEXA) scan to check for this.