What is Ankylosing Spondylitis?
Ankylosing Spondylitis (AS) is a painful, progressive form of inflammatory arthritis. It mainly affects the spine but can also affect other joints, tendons and ligaments.
Ankylosing means fusing together. Spondylitis means inflammation of the vertebrae. Both words come from the Greek language. Ankylosing Spondylitis describes the condition where some or all of the joints and bones of the spine fuse together.
Entire fusing of the spine is unusual. Many people will only have partial fusion, sometimes limited to the pelvic bones. Other areas such as the eyes, bowel, lungs and heart can also sometimes be involved with AS.
What happens in AS?
Inflammation occurs at the site where certain ligaments or tendons attach to the bone. This area of the body is known as enthesis.
The inflammation is followed by some erosion (wearing away) of the bone at the site of the attachment. This is known as enthesopathy.
As the inflammation subsides, a healing process takes place and new bone develops. Movement becomes restricted where bone replaces the elastic tissue of ligaments or tendons.
Repetition of this inflammatory process leads to further bone formation and the individual bones which make up your backbone (vertebrae) can fuse together.
The pelvis is most commonly affected first. The lower back, chest wall and neck may also become involved at different times.
AS is a very variable condition
Some people with AS have virtually no symptoms whereas others suffer more severely. AS tends to affect men, women and children in slightly different ways.
The most commonly affected areas in men are the pelvis and spine. Other joints which may be involved are the chest wall, hips, shoulders and feet.
In women the involvement of the spine tends to be less severe. The most commonly affected areas are the pelvis, hips, knees, wrists and ankles.
It is unusual for children under the age of 11 to develop symptoms of AS. The joints which are typically affected in children are the knees, ankles, feet, hips and buttocks. They are less likely to suffer from back pain. Click here to read more about AS in children.
Is AS common?
AS affects approximately 2-5 adults per 1,000 in the UK. This means an estimated 200,000 in the UK have AS. It usually begins in early adult life with the average age of diagnosis being 24.
What are the symptoms of AS?
Typical symptoms of AS include:
- Slow or gradual onset of back pain and stiffness over weeks or months, rather than hours or days
- Early-morning stiffness and pain, wearing off or reducing during the day with movement
- Persistence for more than three months (as opposed to coming on in short attacks).
- Feeling better after exercise and feeling worse after rest.
- Weight loss, especially in the early stages
- Feeling feverish and experiencing night sweats (especially in theearly stages)
Ankylosing spondylititis and spondylosis
These two conditions do sound very similar but are actually very different.
Whilst ankylosing spondylitis is a form of inflammatory arthritis, spondylosis is a medical term for the general wear and tear that occurs in the joints and bones of the spine as people get older.
Cervical spondylosis specifically refers to wear and tear occuring in the section of spine in the neck (the cervical spine). It causes periods of stiffness and pain in the neck that may spread to the shoulders and the base of the skull. The pain and symptoms vary from one person to another but usually follow a pattern of good days and bad days.
Spondylosis is an age related condition. It is estimated that almost everyone will have some symptoms of cervical spondylosis by the age of 70. This means that people with AS might also start to develop symptoms of spondylosis as they get older.