What is ankylosing spondylitis?
Ankylosing spondylitis is a condition that causes inflammation of the joints of the spinal and of the joints between the spine and pelvis. This results in pain and stiffness in the neck and back.
What causes ankylosing spondylitis and who is at risk?
Less than 1% of the UK population suffers from the condition. Ankylosing spondylitis is more common and more severe in men than in women. It usually begins between the ages of 16 and 40 years.
Although the cause of the condition is unknown, a very strong association is found between ankylosing spondylitis and people who have a blood type called 'HLA-B27'. It is thought that this blood type causes the body's immune system to attack the joints of the spine. Therefore, ankylosing spondylitis is often thought of as an 'autoimmune disease' – a disease in which the immune system attacks the body. As HLA-B27 is inherited (like other blood types), ankylosing spondylitis is much more common in people who parents or siblings have it.
What are the common symptoms and complications of ankylosing spondylitis?
Typically, the symptoms of ankylosing spondylitis come and go. The most common symptom is back pain, which is usually worse at night and in the morning, and is relieved by gentle activity.
Some people may stoop, whereas others often develop a straight, stiff spine. In time, the infection can lead to permanent stiffness, but as the spine becomes more rigid, the pain may actually decrease. If the joints where the ribs meet the spinal are affected, breathing can become difficult and painful. However, only a minority of people who have ankylosing spondylitis develop a rigid spine and chest.
Other joints can be affected in up to one quarter of people who have ankylosing spondylitis. These joints include the hips, knees and shoulders, and the 'sacroiliac' joints, where the spine meets the pelvis at the lower back.
Other features of the disease do not involve the joints, and can include:
- loss of appetite
- general feeling of being unwell (malaise)
- mild inflammation of the eye (iritis)
- rarely, inflammation of a heart valve
- pressure on the nerves of the spinal cord, which causes fatigue, numbness, incontinence and impotence.
As the spine becomes more rigid, it is more prone to fractures.
How do doctors recognize ankylosing spondylitis?
The diagnosis is often clear to your doctor from your symptoms and a physical examination. Blood tests are performed, which may show evidence of inflammation and you may be checked to see if you have the HLA-B27 blood type. X-rays are always done because they show very typical changes, such as inflammation of the sacro-iliac joints and damage to the joints in the spine.
What is the treatment for ankylosing spondylitis?
Self-care action plan
Treatment consists of a long-term program of activity and anti-inflammatory drugs when necessary. You will notice that during a flare-up, your joints stiffen with bed rest. For this reason, people who have ankylosing spondylitis are encouraged to mobilize gently and remain active (swimming helps to keep the muscles strong). You should not use lumbar (back) supports, as they only make the stiffness worse.
Daily exercises such as spine extension and breathing are performed to strengthen muscles and prevent poor posture. It is worth obtaining the advice of a specialist physiotherapist. Remember to sleep on a firm bed with no more than one pillow.
Non-steroidal anti-inflammatory drugs (NSAIDs) such as indomethacin help to reduce inflammation and treat pain. They enable an active exercise program. Corticosteroids are occasionally injected into particularly painful joints and used in drops for eye inflammation (iritis).
Surgery is used to replace hip and knee joints that become too damaged and painful.
What is the outcome of ankylosing spondylitis?
Even though ankylosing spondylitis is incurable, 85 per cent of people have nothing more than a mild stiff back after the initial painful start of the disease. Without the hips and knees are affected, almost no disability results. Only five per cent of people who have the disease become severely disabled.